The accuracy of the AR-15/M16 has always been top rate. For the longest time, when one would think of a long range designated marksman rifle (DMR) you would think of something in 7.62x51mm NATO and more than likely bolt action. During the Vietnam War, it was seen that there is a benefit to having a semiautomatic DMR-type rifle so the accurized M14 appeared. In the calm of the Cold War, little attention was paid to small arms; money was going into nuclear weapons and advanced aircraft. Since the Vietnam War, U.S. troops encountered little combat and small arms would remain virtually unchanged. After 9/11 all that would change. Now with the Global War On Terrorism, infantry battles would be back rather than the high tech air war, which really was the First Gulf War. Prior to that, former Army Colonel Mark Westrom, former President of ArmaLite, Inc. conceived a 5.56x45mm SPR (Special Purpose Rifle); originally envisioned by Westrom to be in 18 inch, 20 inch and 22 inch barrels. The SPR as initially designed was to be an upper receiver that would be adaptable to current M4/M4A1 carbines that would fill two roles. First as a light sniper rifle and then, if need be, it could be used as a light machine gun. There was again no one rifle or carbine available that would fit this particular role so SOCOM would build it. Unfortunately it stopped, at least for a short period of time.

The concept sat dormant for years until SOCOM revived the concept in the 1990s as an initiative by the 5th Special Forces Group. They envisioned the SPR as a Special Purpose Receiver that drops on a standard M16/M4-type lower receiver. This receiver was to be highly accurized and would shoot a new type of 5.56x45mm round – one that would go on to be the most accurate 5.56mm cartridge in the world. The SPR upper receiver would provide a lightweight, compact, long-range precision fire and light support capability to the small Special Operation Forces groups that were not in a position to receive support from aircraft or artillery.

Modified M12 Mod 1. It has the fixed A1 stock replaced with an LMT SOPMOD stock with a six position receiver extension. Although the MK12-series SPRs all came with fixed stocks from Crane, Indiana, once the rifles went to their assigned units modifications were made by the users. Also the Ops, Inc. sounds suppressor is attached. Note the Harris bipod.

SOPMOD Programs Office at the Naval Surface Warfare Center, Crane, Indiana, drafted the requirements desired and went to work soliciting and testing the concept at hand. In late 1998 and throughout 1999, the 5th Special Forces Group collaborated with the U.S. Army Marksmanship Unit (USAMU) at Fort Benning, Georgia, to develop initial prototypes of this new requirement. During the program, SOPMOD funded several prototypes that were made and tested by the USAMU working closely with the 5th Special Forces.

The first SPR prototypes were tested with handloaded ammunition and the concept was solidified with the requirements being realistic and achievable. Several match grade projectiles were tested with weights as high as 88 grains. After rigorous accuracy testing, the 73-grain boat tail match open tip bullet manufactured by Berger was chosen for the SPR program. However, due to the immediate requirement for ammunition to go along with the SPR upper receiver, the Berger factory was in the process of moving and could not deliver the bullets in the needed quantities. With this kink in the chain, a new bullet was needed to fit the requirement. The new bullet would be the Sierra 77-grain Boat Tail Match King. Jeff Hoffman, president of Black Hills Ammunition was charged with designing and producing the ammunition that would both maintain match accuracy and combat reliability of theM16A2 rifle. Based on these findings, in October of 1999, the SPR was validated as part of the SOPMOD requirement. First requirements called for the drop-in SPR for the M4A1 carbine along with the match grade ammunition. Conceptually, there would be a modified M4A1 carbine that would have precision match grade accuracy in a lightweight rifle that could provide semi- or automatic firepower on demand. The rifle is designed as a match grade rifle but if the need would arise the heavy barrel would provide fully automatic suppressive fire.

Finalized MK12 Mod 1 rifle. Note the M16A1 lower receiver that would be equipped with a Knight’s Armament two stage selective fire trigger group. This rifle differs from the Mod 0 with the handguard and backup sights. The handguard used is the Knight’s Armament M4 Match Free-Floating Rail Adapter System (KAC part number 99167) and the KAC rail fore end flip-up front sight (KAC part number 99051). The Mod 1 also uses the KAC 600 meter flip up rear (KAC part number 98474).

All first production SPRs were assembled at NSWC Crane, Indiana. The first 150 receivers utilized 18 ½ inch barrels manufactured by Krieger (50), Douglas (50) and Snider (50 polygonal). Interestingly, the initial rifles used a 20-inch barrel. When it came time to procure, the Navy would not procure a 20-inch barrel because one already existed – the 20-inch M16A2/M16A4 barrel. So a new barrel could be procured to conform with the requirements. The length was reduced to 18.5 inches and that was ok to procure due to it not already being in the inventory. The barrel would use a standard rifle length gas system. The Douglas barrels, primarily based on performance as well as cost, became the barrel of choice. These barrels were attached by an aluminum free-floating handguard to an ArmaLite flat top (M1913) rail upper receiver. Added to the upper receiver was the Swan #38 sleeve rail or Swan Sleeve. SOCOM found that the ArmaLite as well as Colt receiver was approximately .005 too tall and caused some problems. To keep parts commonality with parts available in the supply chain, SOCOM eventually went with as many existing parts in inventory as possible. There were two main triggers in use. Due to the fact the SPR would have to perform as both a sniper rifle and a light machine gun, a match grade trigger was required but also with the capability to fire fully automatic. The first trigger implemented was the Knight’s Armament Company two stage selective fire trigger and the second was Accuracy Speaks single stage trigger. Based on research, it appears that the last production rifles used the Accuracy Speaks single stage selective fire trigger group.

When the MK12 was finalized, the acronym would remain the same but what it stood for would be different. SPR originally meant Special Purpose Rifle; however now it would stand for SOF Precision Rifle or Special operations forces Precision Rifle. Within 12 months, Crane took all their gained knowledge and used it to develop 24 second generation prototypes that were more adaptable to production on a larger scale. As originally envisioned, the upper receiver was designed to be dropped into the M4A1 lower receiver. For any number of reasons, this really was not a good idea. By building a dedicated rifle, it could be designed as an accurized rifle – for instance having a match trigger installed and a longer stock that would be more comfortable than the telescopic stock of the carbine. The host weapon would be the older and outdated M16A1 rifle due to the lack of availability of the M4A1 carbine at the time and a large number of obsolete M16A1 rifles were being turned in to Crane by National Guard and Reserve Units for destruction. In order to achieve the full performance requirements of the SPR, more was needed than just a drop in upper receiver.

A: On the left is the Sierra MatchKing 77gr OTM as first used in the Mk262 Mod 0 ammunition compared to the current Mk262 Mod 1 load on the right with the addition of the cannilure. B: Ballistic gel tests of the Mk262 Mod 1 ammunition provided by Jeff Hoffman, President of Black Hills Ammunition. C. On the left is the early Mk262 Mod 0. Note the 77gr Sierra OTM projectile. On the right is the current Mk262 Mod 1. Note the addition of the cannilure to the 77gr projectile. There were several improvements made to the ammunition from its initial to current load.

In October of 2000, formal testing of the first SPR rifles began at Thunder Ranch in Texas. Combination of operational and technical experimentation showed the remaining weakness that would be corrected before the production run of the second generation SPR rifles. During winter of 2000 and 2001, all the final changes were made and deficiencies were corrected. The first 100 Limited User Test (LUT) was set for large production runs. The plans called for these LUT rifles to be deployed with SOCOM operators overseas by the summer of 2001. These initial deployments allowed the users to evaluate and make suggestions for improvement before the final production run. Most of these initial 100 rifles were called into service due to Operation Enduring Freedom in September 2001 so the field trials were conducted in just that, the field. The SPR has been used with great success with Special Operations Forces engaged in combat in Afghanistan. The SPR is responsible for an extremely high percentage of enemy soldiers engaged and killed with precision rifles. The SPR rifle was now to be named, the Mk 12. There would be two basic models of the Mk12, the Mod 0 and Mod 1.

The Mk 12 Mod 0 and Mod 1 use the same lower receiver. The M16A1 lower receiver is fitted with a selective fire match grade trigger; the Knight’s Armament 2-stage selective fire trigger or the Accuracy Speaks single action trigger. The rifle is designed as a precision shooting rifle, however if needed, with the flip of the selector, the rifle can put down a heavy volume of fire. The barrel would be done as a match barrel after heavy automatic fire but that can be easily replaced if a high volume of fire was needed to save lives. The rifles may or may not be found with the ergo-grip manufactured by Falcon Industries, or with the standard A1-style pistol grip. Many of the lower receivers will have ambidextrous selector levers as well as ambidextrous Norgon magazine catches. Once rifles got to their units/end users, they were also customized for the unit or end user. Various pistol grips may be found and also seen has been telescopic stocks on Mk12 rifles. Due to the rifle length gas system and shorter 18-inch barrel, along with the heavier profile of the barrel, it was found the Mk12 would not run reliably on full automatic with a carbine buffer but would with the standard stock and buffer. However, some felt the shorter stock was worth the tradeoff of difficulty with automatic fire. During research, photographs have been found with Mk12 rifles built on M16A2 lower receivers as well with the 5/8 of an inch longer stock.

Finalized MK12 Mod 0 rifle. Note the M16A1 lower receiver that would be equipped with a Knight’s Armament two stage selective fire trigger group. The rifle uses Precision Reflex carbon fiber free floated handguard with a A.R.M.S., Inc. Swan #38 SPR sleeve and rear sight as well. The front sight is Precision Reflex and the Harris bipod is attached via A.R.M.S. #32 bipod adapter.

The upper receivers for the SPR/Mk12 series rifles utilize the standard flat top upper receiver with feed ramp cuts for use with a barrel extension also cut with extended feed ramps. Early production rifles would use a standard M16A4 flat top upper receiver (no extended feed ramps) and the feed ramps would be cut into them with a Dremel tool. The feed ramps were necessary so the thin jacketed 77-grain MatchKing bullets would not be damaged while feeding. The upper receivers in use are mostly produced by Colt that also includes upper receivers made by Diemaco/Colt Canada. Colt purchased Diemaco May of 2005 renaming the company Colt Canada. Prior to this acquisition, Colt purchased Diemaco manufactured upper receivers for both production M4 carbines as well as spare parts.

In the development stages, three manufacturers of barrels were used and tested; these would be Douglas, Kreiger and Schneider. In final selection, the Douglas barrel was chosen for a combination of accuracy, quality and cost. The barrel is made of high quality 416 stainless steel. This barrel utilizes a 1 turn in 7 inch twist with six lands and grooves and a right hand twist. The 1/7 twist was necessary to stabilize projectiles from 77 to 100 grains (subsonic). The end of the barrel has an Ops, Inc. muzzle brake, which has threads for mounting the silencer. The silencer is made by Ops, Inc. as well. Both incorporate Harris bipods. The rifles may also be found with various sound suppressors. The muzzle brake was very effective but also very loud. Due to complaints about the loud muzzle blast a screw-on flash suppressor was designed. This makeshift flash suppressor slid over the muzzle brake and screwed onto the threads. The concept was excellent and worked well but never really made it out of the prototype stages.

Update done to the Mk12 Mod 0 rifles by Precision Reflex, Inc. in July of 2007. Note the shorter 16-inch barrel and the rail mounted front sight. The rifle has the PRI Gen III forearm and ACE M4 SOCOM stock.

Both versions of the rifle utilize the PRI made Gas Buster charging handle, which is designed to prevent any gas from the upper receiver exiting out of the rear. The Gas Buster charging handle seals the rear of the receiver so the shooter will get no gas in his face. Some operator were known to put rubber ATV around where there were gaps in the fit between the charging handle and receiver to further seal that area from escaping gas.

Both rifles utilize the same main optical sight: the Leupold TS-30A1 and the TS-30 A2. Both are a 3x to 9x variable scope. The A2 model has the option for the operator to use an illuminated reticle. The intensity of the light may be adjusted by the knob on the top rear of the scope. This was the standard optic but you will encounter numerous types of optics in use.

The MK12 Mods 0 and 1 are designed for the Ops, Inc. sound suppressor. In order to accept the suppressor, the Ops, Inc. muzzle brake and suppressor collar are installed on the barrel. On the bottom was an experimental flash suppressor attachment. It was screwed onto the muzzle brake converting the muzzle brake into a flash suppressor. Many users requested this due to the extreme muzzle flash seen with the use of the muzzle brake. It never went to production but was an excellent solution to the problem at hand.

The Mk 12, Mod 0
NSN 1005-01-504-3275

The Mk 12, Mod 0 is carried by the U.S. Army Special Forces Rangers. The Mod 0 has a weight of 11.70 pounds. The major difference in the Mod 0 and Mod 1 is the handguard assembly and the back-up sights. The Mod 0 uses the A.R.M.S., Inc. #38 SPR Mod. Swan Sleeve with the PRI (Precision Reflex Industries) Ged III Freefloat Forearm, which is made from aluminum and carbon fiber materials. The Swan Sleeve goes from the handguard and covers and protects the rail on the upper receiver. At the rear of the rail is the SWAN #40 Stand Alone Flip-Up rear sight. The gas block is made by PRI and has a folding front sight. The front sight post is adjusted for elevation by a dial on the front sight assembly. If the optic was lost, by turning the two throw levers on the scope mount, the scope can be removed and both back-up sights can be engaged and the rifle will be ready for action.

The optics (light sources, bipod, etc.) are attached by A.R.M.S., Inc. throw lever mounts that allow for quick detachment if there is an immediate need to go to iron sights. For scopes, the throw lever mount #22M is used. Both Harris bipods as well as Versa-Pods are used. The upper receiver provided for this article was one of David Dunlap’s original uppers he built towards the beginning of the project. David Dunlap is the President of Precision Reflex, Inc.

The front sight base of the MK12 Mod 0 contains a folding front sight that is adjustable for elevation only.

In July of 2007, Precision Reflex, Inc. rebuilt 12 Mk12 Mod 0 rifles at Fort Campbell, Kentucky. These rifles deviated from the standard Mod 0 in 8 ways:

Replaced the barrels and bolts with a 16” Douglas, 1:8 twist 5.56 barrel – PRI #06-681BB
Removed the barrel mounted front sight with a PRI Rail Mounted Flip Up Front Sight – PRI #05-0028
Added a new gas block with intermediate length gas tube – PRI #05-075-01
Replaced the forearm with a new PRI Gen III Rifle Length Forearm – PRI #05-073-03
Replaced the old OPS Brake and sleeve with a New Ops Brake and Sleeve
Added a new ACE M4 SOCOM stock
Added an Accuracy Speaks full auto trigger
Replaced the Old PRI Gas Buster Charging Handle with new PRI Gas Busters – PRI #05-0031. (Old ones quickly “disappeared” to other users)

The rear sight for the MK12 Mod 0 is the A.R.M.S., Inc. #40 backup sight that has both long and short range apertures and is adjustable for windage only. RIGHT: The Mod 1 also uses the KAC 600 meter flip up rear (KAC part number 98474), which is adjustable for windage only. OPPOSITE PAGE TOP: The Mod 1 uses the KAC rail fore end flip-up front sight (KAC part number 99051) which is adjustable for elevation only.

The Mk 12, Mod 1
NSN 1005-01-504-3276

The Mk 12, Mod 1 is carried by U.S. Army Rangers, U.S. Navy SEALS and the U.S. Air Force Special Tactical Teams. The Mod 1 has a weight of 10.80 pounds and uses many of Knight’s Armament Company’s (KAC) components. The Mod 1 uses the KAC Free Floating RAS (Rail Adapter System) that has full length quad Mil-Std 1913 rails. This rail system does not use a sleeve like the Mod 0. Optics would be mounted right to the upper receiver or the rails on the Free Floating RAS. The KAC folding back-up sight is used on the rear of the upper receiver rail and a folding front sight is used. The gas block is made at Crane. The Mod 1 uses A.R.M.S. #22 High scope rings that attach right to the rail. The Mk12 Mod 1 upper receiver used during the research of this article was provided by Lamont LeClair, active duty SEAL and owner of Centurion Arms. Monty was able to provide much insight to how the Mk12 is used and what it really brings to the table for SOF units.

The New Improved SOCOM 5.56x45mm Cartridge

In 1999, SOCOM requested that Black Hills work with them jointly to develop the MK12 Special Purpose Rifle (SPR) weapon system. SOCOM was to develop the rifle and Black Hills Ammunition was to develop the ammunition the new rifle would shoot. This rifle was to be accurate out to 600 yards. The load would use the proven Sierra 77-grain open tip match projectile of the AMU. To meet the requirements the cartridge must be “militarized.” This included switching from .223 Rem. to 5.56mm cartridge cases, loading to the increased 5.56mm pressures, crimping and sealing the primers and adding flash retardant to the powder blend. Black Hills Ammunition has developed the first 5.56mm sniper cartridge, the MK262 Mod 0 cartridge adopted in 2002.

During evaluation of the new round, issues came up with reliability when the temperatures dropped and the guns got dirty (external dirt, not ammunition). Issues with short stroking when the rifles were in these conditions without sound suppressors were encountered in the cold with the SPR, which uses a 2 inch shorter barrel than the original 20-inch M16A2 gas system the SPR was built on. Black Hills got right on the problems and through switching to a slower burning powder with a pressure curve tweaked for the 18-inch SPR barrel, the MK262 Mod 1 was born. Later during extremely rigorous function testing at Black Hills, when the weapons were fired at rates greatly exceeding the 12 to 15 round spec rate of fire for the M16/M4 weapon system, it was found that the new propellant was more sensitive to heat from the chambers of hot weapons. This resulted in the increased pressure and increase incidences of failure to extract. Black Hills notified NSWC-Crane and set out to work again to improve the load. By working on a powder blend with higher heat tolerance and improving the brass, these issues were overcome. Another issue that needed to be addressed during the product improvement was Black Hills desire to have Sierra manufacture a cannulure on the 77-grain OTM projectile. Sierra feared this would affect the accuracy of the projectile. Black Hills knew that this round is being used in an autoloading rifle and wanted to avoid the possibility that a rough feed could cause the bullet to push back or telescope back into the case, resulting in a malfunction. Sierra agreed to produce the cannilured version of the projectile. The new and final round was named the MK262 Mod 1 in 2003 and with the correction of the temperature sensitive powder the specification changed but remained the Mod 1.

The Mk262 Mod 1 has gone on to be the most sought out ammunition in the 5.56mm line up for the U.S. military. Primarily used Mk12 SPRs, it has also proven to increase the accuracy and lethality of the 14.5 inch M4 as well as the Mk18 CQB with a 10.5 inch barrel. This author has shot a Mk12 Mod 1 at a silhouette steel target at 850 yards consistently, which is way out of the range of a standard 5.56mm/.223 Rem. caliber rifles and ammunition. The combination of rifle and ammunition has served admirably in both Iraq and Afghanistan. Special operations troops have great confidence and there is an interest in clones of this rifle in the commercial market. For someone looking to build a Mod 1, Centurion Arms offers a complete upper receiver down to the last detail including a Douglas barrel. If one wished for a Mod 0, the upper receivers are built and sold by Precision Reflex, Inc.

Issue box of the highly regarded Mk262 Mod 1 ammunition that was designed with the Mk12 SPR.

There are many manufacturers making ammunition as well as remanufacturing it.  Few have a reputation of being precision ammunition manufacturers let alone manufacturing military grade ammunition.  But consider ammunition that is match grade loaded to military specifications?  Trying to bridge match grade accuracy and ability to produce military reliability is very difficult.  Loading any precision round is difficult in mass production.  But there is one company out there that has done it, and that is Black Hills Ammunition owned by Jeff Hoffman and his wife Kristi, who is a co-owner and an integral, indispensable part of Black Hills Ammunition.  This “little big company” has produced the most precise and sought after military ammunition in the industry.  Not only have they produced it, they designed the specifications as well.

Jeff Hoffman was a police officer in 1979 and has served as a police sniper since 1989.  Financially strained, he worked two other part time jobs and Kristi worked a full time job.  In late 1982, the Hoffman’s had an opportunity to buy into Black Hills Shooter’s Supply (established in 1981).  They borrowed $12,000 and bought into the new company.  The company did well selling ammunition and reloading supplies.  In 1988 the Hoffman’s broke off of the Black Hills Shooting Supplies and opened Black Hills Ammunition.  The same ammunition, machines and people; the Hoffman’s took that part of the company and their then partner continued with Black Hills Shooter Supplies.  Working this end alone, the Hoffman’s were financially strapped in this new venture.  But one phone call was a game changer for Black Hills Ammunition.  They had sent the Illinois State Police some sample ammo and they called and said that they wanted to place an order for 700,000 rounds of 9mm ammunition and needed it now!  Jeff was very excited about the order but very nervous about being able to manufacture it in a timely fashion.  One range master, Master Sgt. Norm Higgerson, said he did not care and that he was sending money and Jeff would make the ammo for him.  Jeff did not want to take the money upfront feeling that was a lot of trust on the Department’s part.  Jeff was then assured by the officer that that was no trust at all – if he messed the order up he would get down to Black Hills Ammunition and personally break Jeff’s legs!  Jeff saluted and said “Yes, sir.” and delivered.  That solved the temporary cash flow problem.

Black Hills President Jeff Hoffman training at Asymmetric Warfare Group School in May of 2013. He is shooting a MK12 Mod1 rifle with his Mk262 Mod1 ammunition. (Jeff Hoffman)

Nearly 30 years later, Black Hills Ammunition recently moved into a new 60,000 square foot facility plus a 7,200 square foot warehouse on 10 acres of land.  Black Hills Ammunition has 75 full-time employees and nearly half of them are in the inspection side of the business alone.  They are the only manufacturer in the country that meets all the military safety requirements without waiver for military ammunition manufacturing.  Their reputation is based on quality and precision.  Black Hills is an assembler of ammunition.  They do not manufacture components.  They rely on tight relationships with vendors of projectiles, primers and propellants.  When components arrive at Black Hills, every projectile and cartridge case is checked for uniformity and quality.  These are all checked before any component reaches a loading machine.  The ammunition is assembled with extreme care by employees with years of experience manufacturing premium quality ammunition.  Once the ammunition is manufactured, each round is handled and inspected by a well trained inspector searching for any anomaly (dent, scratch, blemish, crack…) that may cause rejection.  The last step in inspection in loading military contract ammunition is to weigh the completed box of ammunition.  If this weight is off it is an indication that a projectile could have been incompletely manufactured or any other possible deformity.  The key is catching the anomaly before the box of ammunition goes out the door.  In the early days, Black Hills Ammunition was known for remanufactured ammunition.  There were many companies offering reloaded ammunition and he found he was competing at a price point.  However his competition lacked the quality and consistency of the ammunition.  This is where Black Hills truly shined.  Once this was seen in the market place, Black Hills no longer played the low bid game.  Educated customers wanted quality ammunition and they were willing to pay for it.

Military packaging for Black Hills’ famous and in high demand MK262 Mod 1 ammunition.

In 1996, a monumental year for Black Hills Ammunition, they were awarded their first military contract for the Army Marksmanship Unit (AMU).  At the request of LTC Mike Harris (ret), Black Hills bid on a contract for producing V8 load, which was an 80 grain OTM cartridge intended for single loading and shooting 600 yards during slow-fire competition.  This cartridge was hand loaded by the AMU using Vitavouri powder.  There was a catch; the load had to maintain velocity without exceeding SAAMI pressure.  The actual specs for this round were impossible, there was no way to attain that velocity and keep the pressures within SAAMI specifications.  Black Hills loaded the ammunition to the velocity specification using the best possible powders available at the time.  They informed the Army who already knew of the situation and knew of this problem.  However, the Army was happy Black Hills saved them 10,000 psi over the AMU hand loaded ammunition plus it gave them the required accuracy, resulting in Black Hills Ammunition’s first military contract.  The AMU was very impressed with the quality of Black Hills Ammunition and they began to order additional loads including 73 grain Berger and Sierra 69 grain Match King bullets specifically designed for the AMU.  Eventually, Black Hills manufactured ammunition for the USMC Rifle Team and ultimately the Air Force and Navy teams as well.  The ordnance community watches to see what the AMU does because they have such a great competitive team.

Black Hills works very closely with their suppliers; particularly powder manufacturers to get powder blends to perform the specific task of each round.  Over the years Black Hills has loaded 5.56x45mm/.223 Rem ammunition with 69 grain Sierra Match King, 73 grain Berger, 75 grain Hornady A-MAX, 77 grain Sierra Match King and 80 grain Sierra Match King bullets for a variety of marksmanship teams.  Black Hills also loaded 6mm Benchrest, 9x19mm and .45 Auto match ammunition for the US Military.

The Black Hills Ammunition manufacturing facility located in Rapid City, South Dakota. (Black Hills Ammunition)

With the variety of offerings Black Hills had, one particular load became the most popular and was destined to be the most sought after military load in SOCOM.  In 1999, SOCOM requested that Black Hills to work with them jointly to develop the MK12 Special Purpose Rifle (SPR) weapon system.  SOCOM was to develop the rifle and Black Hills Ammunition was to develop the ammunition the new rifle would shoot.  This rifle was to be accurate out to 600 yards.  The load would use the proven Sierra 77 grain open tip match projectile of the AMU.  To meet the requirements, the cartridge must be “militarized.”  This included switching from .223 Rem to 5.56mm cartridge cases, loading to the increased 5.56mm pressures, crimping and sealing the primers and adding flash retardant to the powder blend.  Black Hills Ammunition developed the first 5.56mm sniper cartridge, the MK262 Mod0 cartridge adopted in 2002.

Like every piece of equipment ever developed within the small arms community, the MK262 round went through a development process.  During evaluation of the new round, issues came up with reliability when the temperatures dropped and the guns got dirty (external dirt, not ammunition).  Issues with short stroking when the rifles were in these conditions without sound suppressors were encountered in the cold with the SPR, which uses a 2 inch shorter barrel than the original 20 inch M16A2 gas system the SPR was built on.  Black Hills got right on the problems and through switching to a slower burning powder with a pressure curve tweaked for the 18 inch SPR barrel, the MK262 Mod 1 was born.  Later during extremely rigorous function testing at Black Hills, when the weapons were fired at rates greatly exceeding the 12 to 15 round spec rate of fire for the M16/M4 weapon system, it was found that the new propellant was more sensitive to heat from the chambers of hot weapons.  This resulted in the increased pressure and increase incidences of failure to extract.  Black Hills notified NSWC-Crane and set out to work again to improve the load.  By working on a powder blend with higher heat tolerance and improving the brass, these issues were overcome.  Another issue that needed to be addressed during the product improvement stage was Black Hills’ desire to have Sierra manufacture a cannelure on the 77 grain OTM projectile.  Sierra feared this would affect the accuracy of the projectile.  Black Hills knew that this round was being used in an auto-loading rifle and wanted to avoid the possibility that a rough feed could cause the bullet to push back or telescope back into the case, resulting in a malfunction.  Sierra agreed to produce the cannelured version of the projectile.  The new and final round was named the MK262 Mod1 in 2003 and with the correction of the temperature sensitive powder the specification changed but remained the Mod1.

On the left is the first MK262 Mod0 – notice the 77 grain projectile has no cannelure. On the right is the current MK262 Mod1 which has the cannelure on the projectile.

The effectiveness of this round was not just seen in the MK12 but by the M4A1 and the MK 18 short barrel as well.  Due to the dynamics of this round it offered match accuracy and an increased terminal performance over the M855 ball.  When tested in 10% ordnance gel with the M4A1, the initial yaw of the projectile began 2.125 inches.  The temporary cavity length is 10.125 inches with a temporary cavity diameter of 5.75 inches.  The round performed consistently regardless of the depth of the target whether it is a thin malnourished Taliban or a heavy set adversary.  The M855 round developed a poor reputation; the bullet would pass right through the thin malnourished Taliban not disrupting much tissue at all.  The MK262 Mod1 would take down the target regardless of width.  Even with the short 10.5 inch MK18 carbine, this ammunition had readily been the preferred ammunition for this carbine.  The MK262 Mod1 has become the 1st choice of SOCOM for all of their 5.56mm caliber rifles and carbines and is the cartridge our warfighters use to engage targets well out of the range of the AKs used by the enemy insurgents.  The ammunition provides unquestioned stopping power to the adversary.  Black Hills Ammunition is and has been the sole source for this incredible round.  This author has used this ammunition for a base line cartridge for accuracy for more than 5 years on every 5.56mm rifle tested.

A box of MK248 Mod1 ammunition, which is a .300 Win Mag caliber cartridge firing a 220 grain projectile. Black Hills was instrumental in the development of this round.

Black Hills was at the forefront of the M118LR AB39 PIP (Product Improvement Program) round.  Hoffman was asked by elements of the U.S. Army stationed at Fort Bragg to see if he could look into improving their existing 7.62x51mm M118LR cartridge, which was loaded with a 175gr Sierra MatchKing projectile.  Initial testing showed Hoffman that he could not improve on velocity or accuracy.  Accuracy was consistently 1 MOA with the MK11 Mod0 rifle.  Later Hoffman was contacted by a civilian trainer working with the army who advised that an area that needed to be addressed on the M118LR round was temperature stability.  Hoffman immediately began environmental testing and found the M118LR conditioned to -40 deg F, +70 deg F and +140 deg F.  Results showed the total spread on velocity was 227 feet per second and the pressure spread was 1,8120 psi.  To put that into a real world situation, a 227 fps change would indicate an elevation correction of 6.3 MOA, which is 58 inches and the difference with a 10 mph full value crosswind (90 deg to path) effect is 10 inches.  Black Hills’ input to the Navy resulted in the solicitation for the improved performance round that became the AB39.  Black Hills competed on this solicitation, meeting the solicitation’s higher required performance levels.  The contract was ultimately awarded to Federal based on price but Black Hills was pleased its efforts resulted in another improvement to the U.S. Military sniping capability.  Black Hills produces a 7.62mm load they sell for export that is 100% compatible and equivalent to the M118LR AB39 PIP load.  They have in fact sold this improved load to foreign governments.

A box of Black Hills match grade .338 Lapua Magnum ammunition loaded with a 300 grain Sierra MatchKing projectile.

The main improvements of the new AB39-PIP M118LR are that the cartridge is loaded with a propellant that is much more temperature stable.  The second change is the specifications were written differently, increasing the required uniformity of the lots.  What this meant was that a sniper did not have to try to hoard lots of M118LR from the same lot so he did not have to re-zero and change his “dope” when he switched to a different lot of ammunition.  The new specification made it so the consistency of the ammunition was improved enough so he would not have to change his “dope” when switching from lot to lot.

Another of the Black Hills manufactured (A191) MK248 Mod 1 .300 Win Mag 220 grain Sierra OTM is used in the SOCOM MK13 Mod5 sniper rifles.  An early requirement for the .300 Win Mag cartridge was a 190 grain Sierra Match King projectile with an effective range of 1,200 yards (A190/MK248 Mod0).  Black Hills Ammunition provided some small quantities to the U.S. Government.  Hoffman had sent communication to Crane regarding his belief that the 190 grain Sierra projectile could be improved by the heavier 220 grain projectile.  With Hoffman’s suggestions of improvement possibilities, the .300 Win Mag cartridge got a new requirement established for a 1,500 yard maximum effective range.  Two other objectives were to decrease the effect of wind drift and flash reduced and increase temperature stability as tested in ranges from -25 F to +165 F.  Results of testing concluded that there is comparable velocity retention between 250 grain .338 Lapua Mag and the 210/220 grain .300 Win Mag.  The muzzle velocity of the 220 grain Sierra OTM .300 Win Mag is 2,768 feet per second.  It was also found that there was only a .5 moa difference in the 190 and 220 grain projectiles when compared at 1,000 yards: this is less than typical fine tuning necessary for each rifle/shooter/load combination.  The 220 grain .300 Win Mag met all objectives, could be fired in existing weapons, was less sensitive than the 210 grain VLD, had comparable accuracy and velocity retention to the 250 grain .338 Lapua Mag round and the .300 Win Mag is a significant cost savings over the .338 Lapua Mag ammunition.  There were two areas in which the (A191) MK248 Mod1 was an improvement over its predecessor.  These areas are temperature stability (less pressure and velocity change in internal ballistics as a result of ambient temperature) as well as a reduction of muzzle flash.  Black Hills met these requirements with a new powder blend that included flash retardant.  The work Black Hills did on the advancement of this cartridge was done at no cost to the U.S. government.  This cartridge is devastating when seen in 10% ordnance gel.  The initial yaw is in just .5 inches with a temporary cavity length of 14 inches.  The temporary cavity diameter 7.75 inches with a temporary cavity diameter locations length of 5 inches.  The projectile fragments into many pieces creating significant tissue damage.

Black Hills 7.62x51mm 175 grain Match Hollow Point, which is equivalent to the M118 LR PIP cartridge.

The U.S. Military contract was ultimately won by Federal, but Black Hills efforts again led to improved capability of the U.S. sniper.  Black Hills Ammunition does continue to supply the U.S. military with .300 Win Mag ammunition on other contracts.

Black Hills Ammunition has also done significant testing and development on the .338 Lapua Magnum cartridge.  The quality of this ammunition gets them continuous contracts from the U.S. government as well as foreign military units.  They produce a 250 and 300 grain Sierra Open Tip Match projectiles.

Another very important niche filled by Black Hills Ammunition is their manufacturing of factory proof loads for the gun manufacturers.  These specially designed high pressure loads insure the weapon is manufactured properly.  In mil-standard testing, both barrels and bolts are shot with a proof round and then magnetic particle tested to ensure against stress fractures.  These loads are made in virtually all centerfire cartridges and Black Hills Ammunition sells more than 24 OEMs of this proof ammunition.  Black Hills also provides approximately 30 OEMs with test ammunition so they may function test and test accuracy in their firearms before they are shipped out of the factory.

Manufacturing ammunition for commercial and hunting use is certainly one thing.  Manufacturing military and law enforcement ammunition is another.  At the end of the day, if you miss that deer or bear, the hunting trip is a loss but you go again next year and try again.  If military ammunition fails, that is the soldier’s life on the line.  There is no second chance.  There is a significant amount of pressure and responsibility put on manufacturers such as Black Hills to make our war-fighter the best ammunition possible not to just win the battle but to come home alive.  Hoffman and Black Hills Ammunition continue to work with our warfighter to insure they have the best ammunition available with the ever improving technology of manufacturing of propellants, projectiles and other components.