By Alton P. Chiu

Since attending the analytically driven 2-Day Tactical Pistols Skills course (see Small Arms Review, Vol. 23 No. 5, pages 40-45), this author recently had another opportunity to study from Ernest Langdon at his 3-Day Advanced Pistol Skills class. The class tuned-up basic skills and introduced shooting at moving targets, shooting in low light conditions and cognitive exercises.

Second Reading of the Basics

Befitting an advanced class, Langdon reviewed the basics at a fast pace. He still provided generous individual attention and feedback that enabled the author to relearn material missed during the 2-Day Tactical Pistols Skills course.

The author discovered his grip strength was still lacking as he could not effectively mitigate recoil as the day wore on. Langdon also observed that the author’s front sights dipped below rear sights as the slide slammed back into the battery. After confirming the use of standard pressure ammunition, he advised experimenting with a lighter 12.5-pound recoil spring in a Beretta M9A1. After these changes, the author observed better recoil management and virtual elimination of front sight dip.

The author also picked up new tips during this “second reading” of the basics. Drawing from the strong-side holster under an open shirt, Langdon related a tip of sewing a flex cuff along the leading edge of the shirt. This helped cover the garment to clear the holster. He also tuned-up the author’s draw, teaching an aggressive sweep with the blade of the strong hand, then pushing the hand down and forward to gain a good grip before withdrawing the pistol from the holster. Langdon also offered similar tips for students using appendix carry.

During reloads, Langdon taught us to tuck our pistol-holding elbow into our bodies. This created a consistent index point and steadied the pistol which is especially important when executing on-the-move. During discussions for slicing-the-pie, Langdon advised an aggressive lean to take and hold a slice, in contrast to the slow sideways shuffle until a shoulder is observed, then lean-out method. The author appreciated learning different techniques so he could choose an appropriate tool for the job. Reviewing material provided ample opportunities to relearn or recall items missed during the first reading. The author found this well worth the price of admission.

Moving

Moving while engaging a stationary target is first introduced. Students shot while moving in a circle around a barrel, as well in a figure-eight pattern around two barrels, to experience the importance of fundamentals. Instead of mechanically shooting double-taps, Langdon emphasized shooting individual rounds during rapid fire, complete with individual sight pictures and trigger preps. Failure to do this resulted in misses, as the sights shifted due to shooter movement. Navigating the barrels occupied the conscious mind and tested whether fundamentals were so well drilled that they became conditioned responses.

“Moving target,” using a Bianchi Cup-like setup, is unique to the 3-Day curriculum. Full-sized targets moved at a jogging speed with an estimated 8m opening to engage. The author required almost half of that to present pistol, establish a constant lead and break the first shot. From this, he estimated himself too slow to engage a target dashing across a hallway, and a realistic sideways-profile further reduces hit probability.

Culminating experiences combined both target and shooter movement. Advancing and retreating diagonally to a moving target taxed the author’s concentration. He promptly forgot the appropriate lead and only managed to focus on the sight picture. These exercises provided a good “feel” for the problem and were a fun way to test fundamentals.

Low Light

Langdon focused on handheld lights as they are an essential tool for searching and assessment. Although some police and citizenry equip their pistols with weapon-mounted lights (WMLs) for easier shooting, one cannot muzzle sweep every unknown while searching. Thus, handheld lights are a common denominator between the two activities.

When searching, Langdon prefers the FBI technique where the light is held high to one side and forward of the body. This creates separation should a threat shoot the light, as it is often the only thing visible. Also for this reason, light should be used judiciously. With the threat identified, Langdon advocates continual illumination to pin the target. If the light is turned off, the threat is likely to shift position.

Langdon also emphasized the need for WMLs to activate with absolute certainty; indeed, one such failure occurred during class. With the premise of identification using handheld light, the author found no satisfactory method of activating WMLs without discarding the handheld light as he drew and discharged his pistol. As such, the author found handheld techniques useful as both a backup (in case a WML fails) and as a primary technique as the situation dictates.

Since most handheld shooting techniques are essentially one-handed, strong-hand-only skills form the fundamental building blocks. Langdon presented multiple techniques, then encouraged students to try different ones under different lighting conditions to find ones they liked. The author’s experiences are presented below.

The Harries Technique is stable, though it quickly induces fatigue. The SureFire (or Rogers) Technique requires unshrouded tailcaps (e.g., the SureFire Tactician); the author’s trigger finger scraped against his support hand fingers. Angling the light downwards solved this, but it compromised both lighting and recoil management. The Graham Technique proved unworkable in live fire as recoil caused the author’s hands to separate and turn off the light. Significant pressure could overcome that, but it would activate constant-on for “clicky” tailcaps and discomforted knuckles. Neck Index Technique is favored by Langdon as it naturally aligned the light with target, but glare from the pistol or one’s clothing can detract from the sight picture. Although there is self-illumination, it is not as important a concern in shooting as in searching. The author also tried the FBI technique as he figured no reason to reposition the light when transitioning from search to shoot.

To simulate urban lighting with some artificial lights, students shot during twilight without illumination. In this exercise, Langdon mentioned that a line of drifting impacts were not unexpected. Muzzle flash acts as a flashbulb, searing the sight picture into the brain. Thus, one might be convinced of a proper sight picture despite it having drifted.

To practise with handheld lights, targets were illuminated from different directions. Shooting one at a time, each student could evaluate his own equipment and technique. Absent that, the author would never have realized his light was turning off under recoil with the Graham Technique. Langdon gave valuable instruction and freedom for students to experiment.

Cognitive Exercises

Most training courses, formal or otherwise, merely exercise students’ shooting skills. Langdon inserted drills requiring cognitive function to demonstrate how decision-making can slow down the process. Four targets with different shapes and numbers were presented, and students were asked to shoot the appropriate one by associating it with a topic posed. If “middle-aged” was the topic, a student might shoot a target containing the number “40.” Another exercise was the Casino Drill where one must shoot the appropriate number of shots on the appropriate target. These exercises helped the author discover which of his fundamental skills were not yet practised enough to be conditioned responses.

Conclusion

The 3-Day Advanced Pistol Skills class reviewed fundamentals from the 2-Day Tactical Pistol Skills course; this second reading provided the author much needed skill tune-ups as well as a refresher on tips missed the first time. Considerable time dedicated to both shooter and target movement provided valuable skills necessary for real-world scenarios. Combining multiple tasks tested fundamentals and allowed honest self-assessments of one’s capability. Low light instructions afforded generous opportunities to explore different techniques and build a well-reasoned plan.

Ernest Langdon proved to be as personable and accessible as he was during his 2-Day course. The author, being an engineer by trade, found that Langdon’s analytic approach helped with material absorption and helped the author make educated choices in equipment and technique. The author highly recommends this course.

Scopes around 3-9x cover a majority of rifle sighting requirements: powerful enough for extended distances, but can be dialed down for moving targets close-in. Such a versatile optic is naturally partnered with the adaptable AR-15 modern sporting rifle, with the MK11 and MK12 rifles having done much to promote such a partnership. Over time, scopes in this application (usually termed tactical scopes) have evolved to feature exposed knobs and ranging reticles. This article evaluates a sample of such scopes.

Candidates

All candidates have exposed turrets and reticles marked in miliradians (mil), although some can also be had in minute of angle (moa). Scopes with mismatched turrets and reticles require the conversion of 1 mil = 3.44 moa when inputting observed corrections into the turret.

The exposed turrets are readily accessible for dialing-in corrections and are generally stiff enough to reject accidental bumps. They also feature a resettable zero so that the turrets can read “0” wherever the rifle is actually zeroed. Some scopes with multiple turret revolutions include a zero stop and revolution counter to prevent lining up at “0” in the wrong revolution, causing the user to mistakenly think it is back at zero. With a hard zero stop such as the clutch on Nightforce, one dials the turret down until it stops moving. With a soft zero stop such as shims on Vortex, one must visually reset back to “0” after the turret stop moving (usually less than 1mil below zero).

Larue LT745 mounts with VFZ in front and QD levers in the back.

Terms and Definitions

From the optical perspective, eye relief is the ideal distance between the eye and the ocular lens. While the image may be usable at other distances, field-of-view and image quality are compromised. Eye relief that changes with magnification can be undesirable as it leads to inconsistent head position. Field-of-view (FOV) is self-explanatory and is not influenced by the size of the front objective. That size, denoted by the number after the “x” (e.g., 2.5-10x42mm has a 42mm diameter front objective), drives resolution and light gathering abilities, as well as exit pupil size. A larger front objective linearly increases resolution as described in Rayleigh’s criterion, and it nonlinearly increases light gathering power due to the circular area being pr2.

The exit pupil is the size of the image projected at the eye relief point, and is idealized as the front objective divide by magnification (e.g. 42mm objective at 10x has a theoretical 4.2mm exit pupil). A higher number is more forgiving of poor head position. A 24mm front objective can be challenging to use in low light at high magnifications given that an eye pupil is roughly 2-4mm in full sunlight and 3-8mm in low light. The tradeoff in front objective size is between resolution/light gathering/exit pupil and weight.

Left to Right: Leupold MK4, Vortex PST, Nightforce NXS. Note the revolution indicator on the Leupold is readable only at the “0” mark while both the Vortex and Nightforce implementations are usable everywhere.

To avoid parallax error, a scope must bring the target and reticle on the same focal plane. As an example, driver and passenger will read a speedometer differently due to the needle and dial being on different planes and the slant view angle of the passenger causes parallax error. To remove the error, the reticle focus ring (a.k.a. fast focus eyepiece) is first used to compensate user vision deficiencies. Then the parallax adjustment knob brings the target image into focus on the same focal plane as the reticle. Note that reticle focus is user specific and should be a one-time setting, while target focus varies with distances. SWFA, Leupold MK4 and both Nightforce scopes feature locks on the reticle focus ring, while flip-open scope caps can also reasonably secure the ring.

Another way to avoid parallax is to look directly along the optical axis by centering the crosshairs in the ocular lens. The maximum parallax error, induced when the user’s pupil rests on the edge of the exit pupil, is given by the equation where D is the front objective diameter, T is the range to target, and P is the parallax-free distance. Take the SWFA 3-9x42mm with parallax-free distance fixed at 100yd (manufacturer information), it has a maximum error of 25mm (0.13mil) at 200m, 71mm (0.18mil) at 400m, 117mm (0.2mil) at 600m. Given the error magnitude and mitigation procedure, the author believes parallax adjustment is not necessary and that the chief benefit is a sharp target
at varying distances.

SWAF SS HD 3-9x42mm.

Chromatic Aberration (CA henceforth) manifests as color fringing between light and dark objects which causes the image to lose sharpness. Different colors have different wavelengths and refractive indices for the same lens; this is why a prism can split white light into the rainbow spectrum. As such, focus error is varying as a function of wavelength (e.g., zero error at only one wavelength). Keeping in mind that CA is eliminated if focus error is zero at all wavelengths, note that adding lenses together changes the error function into a second-order shape for achromatic (2-lenses) and third-order shape for apochromatic (3-lenses) for a flatter line which reduces focus error across the spectrum. However, more lenses mean more weight and cost.

On mechanically related matters, First-Focal-Plane (FFP) or Second-Focal-Plane (SFP) indicates where the reticle is placed. Reticle in SFP stays the same size independent of magnification, so the mil hash mark is only true at one magnification (usually the maximum). Reticle in FFP changes size, so the 1mil hash mark holds true across magnification. An illuminated reticle can be useful at night if dim enough to not overpower the target, and one can cover the front objective with a cap for use as an occluded gun sight during daytime at close-range. Lastly, some of the candidate scopes can be equipped with a Bullet-Drop-Compensator (BDC) turret which is marked in range. While easy to use, a BDC is only pinpoint accurate for a particular cartridge and atmospheric conditions.

Burris XTR II 2-10x42. Both the parallax and illumination adjustments are on the left side.

Optical Performance

The author found the brightness and clarity of all candidates more than adequate for sighting purposes with none exhibiting bad lens flare. In fact, the SWFA and Nightforce x32 front objectives are set about 25cm inside the body and act as an integral sun shade. This section addresses optical artifacts that may cause eye fatigue or hinder speed: chromatic aberration, color cast, distortions, and eye box. Readers are reminded that the following evaluation is subjective to the author. Readers should also note that optical performance is degraded when the turrets are near their travel limits.

The SWFA has visible CA at 9x for far targets, but is well controlled at the 100yd parallax-free distance. The Leupold VXR has similar performance. The Vortex, Burris, and both of the Nightforce all have less CA that is still noticeable if carefully examined at maximum magnification. Leupold MK4 requires the eye to be positioned directly on the optical axis to obtain a nearly CA free image, but the image quality rapidly degrades when off axis.

Nightforce 2.5-10x32mm.

SWFA and Leupold VXR are color neutral and fairly vivid at 3x, only falling off towards 9x with some purple tinge. Vortex and both Nightforce renders a rich image; but while Vortex has a visible purple tinge at 10x, both Nightforce only have a slight outline at 10x. Burris is color neutral but has noticeable purple tinge at 10x. In comparison, Leupold MK4 renders colors somewhat flatly with a cool cast across the magnification range.

Distortion is another optical artifact that can affect scope use. Barrel distortion is an artifact where a column of straight lines are rendered in a bulging manner akin to the stakes of a wooden barrel. Petzval field curvature is where a flat object (e.g. wall) is rendered on a curved image plane, such that only the central part is sharp. Tunneling is a phenomenon where, as magnification decreases, the image itself no longer fills the ocular lens and the black band between the image and ocular bell increases in size.

SWFA has noticeable tunneling from 3x to 4x accompanied by slight barrel distortions, and is not as sharp for distant targets due to the fixed parallax. Leupold VXR also suffers a lesser degree of tunneling from 3x to 3.5x. Vortex is sharp across the image with some fuzziness near the very edge. The Burris is distortion free at 2x, but has Petzval field curvature at 10x which causes smearing and noticeable CA at the edges. Leupold MK4 has slight tunneling from 3.5x to 4x, and slight distortions at the very edges throughout the magnification range. Lastly, the Nightforce x32 has noticeable barrel distortion at 2.5x which are mostly gone by 5x, causing the author some disorientation when panning for a moving target. The x42 scope has some barrel distortion at the outer fringes at 2.5x. Both are distortion free
and sharp at 10x.

Nightforce 2.5-10x42mm.

Eye box refers to a combination of eye relief and exit pupil. As expected, the author found all scopes with 40/42mm front objectives much easier to mount than those with 32mm front objectives. This is especially true for low-light conditions when the pupil has dilated. Vortex has a noticeable black edge between the image and eyepiece, creating a sucked-in feel. In contrast, both Leupold candidates and the SWFA leave very little black space and feel less claustrophobic. Both Nightforce ocular lenses are not inset much from the eyepiece, but there is a noticeable black edge which can bleed into the image under the right lighting conditions. In addition, both Nightforce scopes seem less forgiving in eye relief as there is very little distance between having the ocular ring obscures the full image, to having the image not fill the ocular lens. As to the Leupold MK4 that varies eye relief with magnification, the author found it bothersome but workable especially since 10x is used typically in prone, which positions the head closer to the eyepiece anyway.

Mechanical Evaluation

A positive and relatively stiff click is necessary on the turret to prevent accidental changes and to provide users feedback. SWFA turrets are tactile with the right amount of resistance, but are not very audible. While the clicks are not mushy, they do not “clunk” into place either. The turrets also have a slightly sharp edge on the cutouts. Leupold VXR turrets have audible and tactile clicks, but are too easily moved. Curiously, both windage and elevation knobs move easier in one direction than the other. In addition, they lack revolution counters and zero stop, so one can easily get lost in the dials. Vortex turrets are comfortable in hand with tactile but not too audible adjustments. They also feature fiber optic to indicate the zero mark. Burris elevation turret is very stiff and positive that became easier to move after break-in, while the windage turret is just as stiff but less positive. It is also the only scope amongst those evaluated to have 10mils per revolution which can take a 77gr 5.56 cartridge to around 800m when using a 200m zero, obviating the need to track revolutions for most scenarios. Leupold MK4 M5 turrets have sharp edges that are not comfortable to adjust with bare hands. Initially, the elevation turret is stiff and reasonably positive but windage is very mushy. There are significant improvements after cycling the turrets from one end to another multiple times: the elevation clicks are audible and crisp while the windage clicks are now audible if still mushy. However, the revolution counter is not user friendly because it is readable only at the “0” mark and the revolutions are unnumbered while lacking a zero stop. In contrast, Nightforce turrets feature very crisp, audible, and positive clicks that while stiff enough to lend confidence, are easy to dial and easy on the hands.

Leupold VXR Patrol 3-9x40mm.

The magnification ring on every scope feels very smooth with the Leupold VXR with just a trace of grit. Both of the Nightforce feature a “Power Throw Lever” that helps in changing magnification rapidly without breaking the shooting position. Similarly, both of the Leupold scopes feature a small nub that is unobtrusive but achieves the same goal. For other scopes, there are aftermarket “cat tails” that clamp onto the magnification rings for the same effect. Of note is the SWAF magnification marking that proves impossible to read from a shooting position.

Handling Impressions

The author was surprised by the change in handling of a lightweight AR-15 due to the center-of-gravity and weight of various scopes. Both Leupold MK4 and the Vortex have roughly the same weight, but the Vortex balances 25mm aft of the Leupold. The reduced rotational inertia makes a Vortex equipped rifle much easier to swing. The Burris weights only about 4oz more than the Leupold MK4, but it makes the rifle feel top-heavy.

Aside from physical attributes, reticle design also heavily influences the target acquisition speed. SWFA features a reversed German #1 reticle with the heavy post on top and extended mil marks on the bottom. The author found the heavy posts to be too distracting at max magnification but does an excellent job of drawing the eye to the center at low magnification. The Burris reticle strikes a better balance and the mil marks are large enough to read at about 4x against a light colored background. The 0.1mil marks of the Nightforce SFP MIL-R reticle are too fine to be usable, and the crosses on the vertical bar and the downward hashes on the horizontal bars make the reticle feel too busy. The mil marks on the Vortex is usable at lower magnifications even when the marks themselves are indistinguishable (starting about 7x) because of the numbering. In contrast, the marks on the Leupold TMR reticle are not visible below 6x on anything but than a white background.

Leupold MK4 LRT 3.5-10x40mm. Note the nub on the magnification ring that is unobtrusive and offers good leverage.

To compare the utility of SFP and FFP reticle at intermediate magnifications, the author compared using holdovers with the FFP Leupold MK4 and SFP Nightforce x42 at 5x where the former acted like a duplex reticle and the latter still had visible hash marks. A healthy amount of changes were dialed into both elevation and windage to give a random impact point. The author fired into a dirt berm and proceeded to walk the splash onto target with holds. On average, it took the FFP one more round than the SFP to hit because the visible marks allow for a more systematic approach. The tradeoff is that if one must dial down the magnification (e.g. falling light) and use the reticle to range or holdover, then mental math must be performed. While it is difficult to determine whether FFP or SFP is a definite winner, there are scenarios where one would be superior.

Conclusion

Despite the author’s nit-picking, all evaluated scopes are fine pieces of kit. Optical performances as well as turret feel are mostly subjective, and the differences are subtle and only apparent when compared side-by-side or under challenging conditions. The biggest discriminator aside from price is the feature-set such as FFP or illumination. SWFA SS 3-9x40mm delivers a no frills scope that performs well for a very reasonable price. Vortex PST 2.5-10x32mm is a light-weight feature-packed scope that has good optics at a reasonable price. Burris trades some optical performance for 10mil per rev turrets and larger front objective. Leupold MK4 3.5-10x40mm gives up some of those features for better optics at nearly double the price. Lastly, the excellent optics and mechanics of Nightforce is reflected in their price.

Top to Bottom: SWFA 3-9x42mm, Leupold VXR Patrol 3-9x40mm, Vortex PST 2.5-10x32mm, Burris XTR II 2-10x42, Leupold MK4 LRT 3.5-10x40mm Front Focal, Nightforce NXS 2.5-10x32mm, Nightforce NXS 2.5-10x42mm

Left, Sphinx SDP. Right, SIG P6. Note the smaller purchase on the SDP slide.

Because some of the slide is covered by the frame, there is less purchase available for manipulation, and this is amplified by the strong recoil spring. One can feel two distinct stages in cycling the SDP: the first 15mm is relatively easy, but the rest takes more strength. While the author had no trouble cycling the slide, two female testers found it nearly impossible despite the respectable slide serrations. This could present a challenge in performing a traditional chamber check where the slide is slightly withdrawn so brass can be clearly seen or felt. Instead, the SDP features two loaded chamber indications: a bump on the external extractor standing out of the slide and a 1mm gap between the slide and right side of the barrel where brass can be seen. The SDP may benefit from “charging supports” similar to that found on the HK VP9, and a straight edged rear sight to assist in one-handed manipulation.


The SDP barrel showcases how Sphinx evolved the CZ 75 design. It shares the enclosed cam track that unlocks the breech via the slide release lever pin from the CZ 75 design, which itself is derived from John Browning’s 1911/Hi-Power. But having the barrel hood locking up against the ejection port follows the practices of current designs such as SIG and Glock, whereas the CZ 75 utilizes the John Browning design (also seen in the 1911/Hi-Power) where cams on the barrel lock into recesses in the slide. In addition, the SDP features polygonal rifling that the author found to ease the cleaning process. Happily, the very tight barrel to slide fit of the CZ 75 is continued in the SDP, no doubt promoting consistency. It is noteworthy that CZ evolved their design down a different path in the P07; like a SIG P-series, it features an open cam track, lockup via barrel hood and ejection port, and traditional rifling. In addition, the P07 features an entirely polymer frame and the slide rides in two steel inserts embedded in the polymer, similar to the current Glock or HK designs.

Sphinx SDP

SDP barrel features good chamber support, though it is marginally less than that found on the P6. The feed ramp on the SDP is polished and is entirely on the barrel. The P6 feed ramp is partly on the barrel and partly on the steel locking insert. Using ball and hollow-point, hand-loaded and factory ammunition, both pistols functioned reliably and produced no bulged cases.


Bore axis is defined as the distance between the bore and web of the shooting hand, representing the moment between the recoil force and the rotation point. It stands to reason that lower bore axis generates less muzzle flip. While the SIG P6 has a marginally higher bore axis than the SDP, the author actually found better split times with the P6, though this can be attributed to his familiarity with the SIG.


The SDP field strips the same way as the CZ 75. The slide is moved slightly back until the hash marks line up on the slide and frame, and then the slide release pin is pushed out and removed. The slide is then free to move forward off the frame, the captured recoil spring withdrawn from the slide, and the barrel removed for cleaning. This is similar to the 1911 and Hi-Power designs, but those pistols require the slide to be drawn further back and while the safety lever holds the slide in place, the slide release is withdrawn. In comparison, the P6 strips much more easily with the slide release holding open the slide and the take down lever rotating 90 degrees before the slide can be withdrawn from the frame. While both female testers had some trouble holding the SDP slide open and pushing out the slide release lever pin, neither had much trouble field stripping the P6. The captured recoil spring of the SDP, in contrast to the P6, is a nice touch to avoid launching parts across the room.

Both field strips similarly, but the P6 is easier to strip.

Unlike Beretta/HK/CZ P07, the SDP decocker does not slam the hammer (driven by the hammer spring) onto the firing pin block or half notch intercept. Like the P6, depressing the decocker unlocks the hammer and releasing the decocker lowers the hammer. The SDP decocker cams-over at the halfway point and the hammer reach the half notch intercept with some vigor. In that respect, it is closer to the SIG SP2022 than the classic P-series. The SDP decocker has a small shelf that aids in lowering the profile of the pistol, but the author found it difficult to use with one finger. Instead, he prefers to actuate the lever with both the thumb and shooting finger on both sides
of the frame.


The author favors DA/SA hammer fired pistols for safety and the ability to thumb cock for an accurate first shot (versus a striker design like the P99AS). Unfortunately, the abbreviated hammer of the SDP is difficult to manipulate because of reduced surface area. Also of note is that once fired, the hammer rests flush against the slide and cannot be manually drawn back. This could hamper the clearing of a dud round where one must overcome both the hammer and recoil springs to extract the faulty round. A workaround would be to pull the trigger slightly until an audible click is heard, in order to put the hammer in the half notch intercept position, then use the thumb to fully cock the hammer. In contrast, the P6 hammer returns to the half notch intercept after firing and can be manipulated to relieve the hammer spring pressure before extraction. The author would like to see Sphinx releasing a full sized hammer to address these concerns.


The slide release is located in the same place as the 1911/Hi-Power/CZ 75, and is more easily reached by the supporting-hand than shooting-hand thumb. Because the slide release must be removed for field stripping, it cannot be ambidextrous or reversible; left handed shooters must utilize the sling-shot method for releasing the slide. Given the author primarily uses a SIG, he did find it somewhat slower to wait for the support hand to release the slide rather than releasing it with the shooting hand thumb right when the magazine seats, but that can be mitigated through training. Like the decocker, the slide release has a small shelf that the author found difficult to actuate quickly, and both female testers resorted to the sling shot method.

SDP tactile loaded chamber indication. The ridge on the extractor stands proud of the slide.

The SDP is equipped with a rubber recoil buffer to soften the firing impulse and promote durability. Post-WWII Walther P38 and early P1 utilized an aluminum frame to reduce weight, but experienced frame cracking from the impact of the steel slide. Improved P1 addressed this with a wider slide to reduce slide velocity, and a steel pin in the frame to absorb the impact. SIG P6 evolved that concept so that the steel locking block serves to both absorb the slide impact and to cam the barrel down and unlock the breech. Like the HK P9S, SDP features a rubber-like buffer that is separate from the recoil spring and softens the blow.


The SDP upper frame comprises of the aluminum chassis containing the full length rail and fire control components, and a polymer lower frame that forms the grip. The two parts are attached via screws under the front of the trigger guard, near the magazine release, and presumably in the rear near the hammer spring. The author found the two parts solidly and seamlessly attached. The Alpha line utilizes a polymer grip, other lines (e.g. Krypton, Sand) utilize an aluminum lower frame, and the Stainless Steel line uses stainless steel for both parts of the frame. The user-changeable polymer grip panel, while soft and lacking aggressive checkering or stippling, does not slip when wet and is very comfortable. When changing the grip, the user must take care to align the rails on the lower frame to the troughs in the grip, and lightly pinch the grip to seat it. Failure to do so would result in some flex on the sides. The author found these grips vastly superior to the hard plastic checkered grips of the P6.


The SDP features a comfortable beavertail like that found on the P229 Elite. However, the author believes slide/hammer bite is not a great danger and the beavertail merely adds a printing factor when carrying concealed.

P6 has marginally more chamber support. Both have similar barrel length.

Finally, the frame over slide design means plenty of places to rest the support hand thumb when using a thumbs forward grip. In fact, the author found the lettering “SPHINX, MADE IN SWITZERLAND” a good tactile index for the thumb.


Shooting Impressions


SDP rear sight is a plain black U-notch type typically found on target pistols, and it features fine serrations to cut down glare. The channel between the “U” is marginally wider than the P6 or Glock 17, presumably to allow faster sight alignment in the absence of “3-dot” or “bar-dot” arrangement. In practice, the author did not experience increased lateral dispersion. However, he favors the “bar-dot” arrangement typically found on German made SIGs and would love to see such an option for the SDP.


Testing was performed with factory 115gr Winchester “White Box” ammunition, and hand-loaded 147gr 0.356” round-nose plated projectile from Xtreme placed atop 3.2gr of Red Dot powder and a CCI #500 primer (the author makes no claim on safety or performance of this load). As an aside, the author shot both loads in a dim indoor range and noticed the 115gr produced more muzzle blast and flash even in the longer barreled Glock 17. The 147gr also generated a softer recoil impulse and impacted higher than the 115gr.


The author found the SDP to require a “cover-the-target” hold familiar to SIG users. At 5yd, 147gr point-of-impact is about 4cm lower than the top of the front sight and roughly matches the white dot painted on the front sight. It appears the front sight, being screwed into a lengthwise slot, can be replaced without changing windage. Sphinx should consider shipping the pistol with an additional, lower, front sight for those preferring a “6 o’clock” hold.

SDP visual loaded chamber indication. Brass is visible between the slide and barrel.

While the SDP double action trigger did not initially feel as smooth as the worn-in P6, it improved quickly and the author expects it to wear well. With the original, heavy, hammer spring in the P6, the author registered low hits in double action because the trigger finger pulled the nose low; this was alleviated by substituting a lighter P225 spring. The author experienced the same problem with the heavy double action trigger of the SDP, and is looking forward to having a lighter hammer spring.


The SDP single action trigger, just like the P6, can be best described as a “rolling trigger” rather than a “glass rod trigger” typically found in tuned 1911s or match rifles. There is a long “take-up” inherent in DA/SA design before hitting a well-defined “wall.” Amounting to about 1mm when measured at the tip of the trigger, the creep is evident only when one is consciously trying to feel it. Similarly, a Glock trigger can feel stiff and bumpy when shooting bullseye, but that feeling goes unnoticed when shooting fast. The SDP trigger does not stack before the shot breaks. The author prefers a “rolling trigger” because it reinforces a smooth stroke, rather than a sudden jerk that results from trying to time a shot. The author also notes that the trigger at rest contacts the frame and wears it down to bare aluminum after only 200 rounds.


The SDP trigger reset feels average like the P6, but its strong trigger return spring distinguishes it. The author does not ride the trigger reset, but prefers to release the trigger fairly far forward before “prepping” it for the next shot. The author appreciates how the strong trigger return spring propels the finger forward and gives positive feedback.


The author conducted an informal test by shooting the SDP and P6 as fast as possible at 5yards while keeping the groups within 3inches. The aforementioned 147gr hand-loaded ammunition was used. For an eight shot string, the SDP split time averaged 0.71secs, and the P6 averaged 0.65secs. The author felt that the P6 had more muzzle flip, but his familiarity with the firearm allowed for faster recovery. In addition, the author needed additional time to align the sights of the SDP while the bar-dot arrangement of the P6 felt more intuitive.

The SDP has more places for the support hand thumb and feels more comfortable.

Final Thoughts


The Sphinx SDP has excellent fit and finish and is both accurate and reliable, just like the SIG P6. While the SDP has superior ergonomics for a typical user, it falls short on ease of manipulation across demographics: both female testers had trouble cycling the slide and actuating levers. This gives pause to selecting the SDP as a defensive firearm for those typically with lower hand strength such as females or the elderly. If designated as a home defense tool, it is advisable to ensure the entire family can manipulate the firearm.


Considering the CZ SP01 and P07 are about half the price of an SDP, prospective buyers would be well advised to handle and shoot each to ascertain if the SDP is worth the premium.


The author would like to see the following as improvements or options:


1. Add charging support similar to those found on the VP9
2. Rear sight with perpendicular leading edge for one-handed manipulation
3. Bar-Dot sight setup with a narrower rear sight channel
4. Include additional front sight from factory that would give a 6 o’clock hold
5. Full hammer
6. No beaver tail
7. Lighter hammer spring

The sights are secured by Allen screws, and it seems windage will not be affected by front sight replacement. Also note the small shelves on the levers keep the profile slim.

Aft of the screw is the recoil buffer.

Manually cocking both hammers. SDP (bottom) has significantly less purchase than the P6 (top).

Profile of medium grip.

The trigger at rest contacts the frame, and at about 200 rounds, that contact has worn thru the finish into bare aluminum. Also note the depression at the bottom of the grip to allow manual extraction of the magazine if it does not drop free.

Top, fired. Bottom, decocked. Note the hashmarks that are lined up for disassembly.