Growing Pains: The SIG Sauer P320 RX Compact

By Todd Burgreen

The Evolution of SIG’s Modular Striker-Fired Handgun

The SIG SAUER P320 was introduced at the 2014 SHOT Show. The P320 is SIG’s response to trends in the U.S. market, which continues to expand and generate firearm sales among both civilians and law enforcement (LE) consumers, with striker-fired handguns leading the way. The striker-fired polymer-framed P320 is a departure from traditional SIG SAUER handguns, such as the P220 and P226 series, which are more traditional steel-framed DA/SA hammer-fired designs. Polymer-framed striker-fired handguns such as the SIG P320 are inherently lighter, thinner and simpler due to the reduced number of parts involved. This makes the gun easier to maintain and ultimately more reliable. The relatively quick adoption of striker-fired weapons for LE use bears out this truth. Striker-fired weapons work without the standard hammer that is visible on early modern semi-automatic pistols. Instead, the firing pin, or “striker,” sits captive under some spring tension inside the slide while the gun is not being put through the firing process.

The SIG SAUER P320 model handgun has again been prominent in the firearm news of late. Its selection as the U.S. Army’s new sidearm via the MHS (Modular Handgun System) Program trials made headlines and ruffled competitors’ feathers for sure. On the other end of the spectrum, the P320 recently received negative attention due to drop test concerns raised by various groups. The parameters used by these groups in their drop tests went beyond industry standard protocols. Nonetheless, SIG SAUER was quick to respond with an upgrade program, recognizing it was only the right thing to do.

The P320 upgrade had been underway for nearly a year before the drop test storm broke. Understandably, the firestorm created by the drop tests forced development into overdrive. A lighter mass trigger shoe, striker pin and sear design are at the heart of the upgrade. Thanks to the upgrade being in its final stages, the new parts had already been extensively tested. Happily, the new components not only improved the trigger system’s safety but also its pull weight and overall feel. Now that the elephant in the room has been addressed, let’s get into the details of the current P320 system.

The P320 benefits from innovative design features found on an earlier, if not so well received, SIG SAUER offering: the P250. Many heralded the SIG SAUER P250 as the next stage in handgun development, when it appeared with its fire control chassis and modularity, but it still received a cool reception from consumers. Nonetheless, the passage of time certainly seems to have validated the P250 concept—particularly considering the recent success of the P320. The SIG P250’s across-the-board modularity in terms of grip size, frame interchangeability combined with various slide lengths, multiple trigger positions and caliber swapping set the bar for the next wave of high-capacity striker-fired polymer-framed handguns. The SIG P250’s adaptability to the needs of individual shooters seemed too good to be true. The shooting public felt that further proofing was required, and they also disliked the trigger. The P250’s trigger pull was similar to that of a double-action revolver in length and long reset. SIG SAUER knew that the modularity of its P250 concept was effective and turned to a striker-fired design to breathe life into the platform with the P320.

The heart of the SIG P320 is the fire control mechanism or chassis. (For clarity’s sake, SIG SAUER refers to it officially as the serialized stainless-steel frame.) The chassis is considered to be the pistol and bears the required serial number marking. The chassis is the key component allowing for the SIG P320’s modularity. The fire control chassis fits into a grip module. While the P320’s grip size may change based on user preference, the position of the slide and magazine releases will be instantly familiar. The SIG P320 does not sacrifice ergonomics, featuring ambidextrous slide levers and the ability to switch magazine release to either side of the frame. Key to the SIG P320’s success are its minimal operating controls, high cartridge capacity to size ratio and relentless reliability.

The SIG P320 features a trigger pull measuring approximately 6 pounds. An advantage of the P320 is that the trigger pull is the same every time. Overall, this consistency makes the SIG P320’s trigger a valuable asset. Anyone who familiarizes themselves with it will not be disappointed. The fire control chassis aids in reducing the number of parts in the SIG P320. The chassis contains the trigger mechanism, hammer and slide catches. The slide assembly does not interact with the grip module, but is guided/operates along the chassis integral steel rails located on both sides of the chassis front and rear. The fire control chassis is easy to swap between grip modules without any tools. Rotate the takedown lever and remove the slide, then pull out the takedown lever by twisting and pulling simultaneously. This frees the fire control for removal by pulling/pushing it upward while drawing the hammer backward, allowing the trigger to move into a position from which it can exit the trigger housing. You are done. Reinsert into another grip module in the reverse order of direction. The SIG SAUER operating manual details this in only two pages, most of which is largely graphics. An important nuance pointed out in the SIG SAUER literature is that the P320 can be field stripped both without tools or pulling the trigger. Anyone who is familiar with what concerns LE administrators knows that this is an often-heard gripe against some SIG SAUER competitors for safety or logistic reasons.

Grip modules are labeled as “Full,” “Carry,” “Compact” and “Subcompact.” The grip modules are further adaptable to individual preference with three different grip circumference sizes available: large, medium and small. Further compounding the P320’s modularity is the availability of slide assemblies in “Full,” “Compact,” or “Subcompact,” with each label signifying barrel length. The ease with which modules and slide assemblies can be switched out makes SIG’s commitment to modularity with the P320 obvious. Multiple specialized P320 slide assemblies are coming on line and rounding out the modularity of the system. An example of this is the RX slide assembly featuring the SIG ROMEO1 reflex sight.

The SIG P320 RX Compact featuring the ROMEO1 has been garnering attention with the upsurge of red dot sights (RDS) being mounted on handguns. Recent events illustrate what a dangerous world we inhabit, with terrorist attacks growing in frequency. If a hostile situation is encountered, the civilian will most likely be defending themselves with a handgun. A handgun is definitely not the optimum choice, especially when compared to a rifle. A handgun is a compromise between portability and performance. One solution was the same as most had already implemented with their rifles: add a red dot sight.

Handgun sights have remained constant or stagnant, depending on your point of view. While materials, operating methods, capacity and calibers have evolved, the earliest muzzle loading pistols feature sights that we can recognize today, in the form of a front post and some sort of rear notch with which it is aligned. Yes, modern open sights are more refined, but the basic form is the same—align the front post within the rear notch.

The quest to improve handgun performance arrived at improving the sighting system via installing red dot sights (RDS) in lieu of the traditional iron open sights for everyday personal defense weapons, LE and military weapons. Competition handguns have sported enhanced sights in the form of red dots or magnified optics for decades now; however, a movement is currently underway to incorporate red dots into everyday concealed carry or personal defense handguns. The previously applied red dots were big and ungainly affairs with complex, oftentimes custom mounts; they were generally utilized for a “gaming” application and less than hardy for everyday carry. This is not the case with the current RDS offerings coming on line, such as that incorporated into the SIG SAUER P320 RX Compact.

SIG SAUER Marketing benefits significantly from access to the SIG SAUER Academy—both the range facilities and, more importantly, personnel. Arm-twisting and hard selling techniques are not required. The best way to let anyone learn or appreciate a product is to let them use it unhindered and without conditions. For example, when it came to the P320, I was fortunate to have been part of a small group of writers given access to all imaginable 9mm P320 components/options and then handed over to SIG Academy instructors. The P320 RX Compact soon proved a favorite configuration. Multiple scenarios—including shooting/moving, engaging multiple targets from behind barricades while switching magazines, working in/around a vehicle and then running steel plates from between 10 yards and 125 yards out—left no doubt of the P320 RX’s potential. SIG SAUER 9mm ammunition was plentiful to say the least.

After multiple days spent at the SIG Academy, further evaluation was made possible at my home range—Echo Valley Training Center (EVTC). Initial T&E priorities included making sure that the P320 RX Compact’s reliability was not compromised and that the SIG SAUER ROMEO1 red dot was a worthy addition that increased capability beyond what was expected from a normal iron-sighted handgun. A concern based on brief handling of other handguns equipped with red dots was being able to orientate the ROMEO’s dot on target just as quickly as with traditional iron sights, especially in quick/fast close-range affairs. SIG SAUER’s use of suppressor-style iron sights bracketing the red dot not only allows them to act as back-up sights, it also quickly fixes the shooter’s eye to the red dot stationed above the front post.

Point shooting with the SIG SAUER P320 RX Compact is still entirely possible using the ROMEO’s window as a ghost ring—albeit a large ghost ring—if forced to react spontaneously to a threat. It was determined that the ROMEO red dot sight assisted in engaging targets, with the red dot easy to pick up rapidly. Both eyes open is strongly suggested; it is a must to get the most out of the RDS concept. The SIG SAUER ROMEO1 offered the capability to engage multiple targets in rapid sequence with faster and more accurate transitions between targets than when using open sights. Speed drills involving plate racks and dueling trees were run with the P320 RX and iron-sighted handguns. The advantage offered by using red dot sights in the competition environment is well known. The ability to place the red dot on the plate without having to align the front and rear irons proved allowed much quicker transitions from plate to plate. This is because the SIG ROMEO1’s 3 MOA dot can superimpose an aiming point on the target while not totally obscuring the target, as the dot is not too large. The SIG ROMEO1 sight withstood the recoil and heat generated by repeatedly long strings of fire. The ROMEO1 weighs 0.8 ounces, which aids its ability to withstand the inertial forces experienced as a slide reciprocates.

As many “maturing” shooters can attest, the single focus plane of the red dot is easier to use accurately than front and rear sights. They can now do as nature intends for them to do, focus on the threat. Moreover, because a red dot is far easier to index than pieces of steel, shooters find they can perform beyond what was considered possible with iron sights. This is all simply because the concept uses the eyes in a more normal manner.

Accuracy levels with the P320 RX Compact lived up to SIG’s reputation, producing sub-3-inch groups at 25 yards. More importantly, performance during more dynamic drills exceeded expectations. The initial experience at the SIG Academy was relived at EVTC, with the accuracy realized during drills proving superior to that during prior testing with iron sights. Bullet strikes on targets were tighter and more centered thanks to the ROMEO1 red dot.

The base model P320 is steadily proving a worthy handgun that is finding appeal with our military, federal agencies, LE departments and civilians based on its flexible modularity catering to shooters of all shapes and sizes. This was a big reason why the P320 was awarded the Army contract. The dream of any end user attempting to pick one handgun model is that it will perform every imaginable job description with equal aplomb. The SIG SAUER P320 achieves this quest.

The SIG SAUER P320 RX Compact’s features mean nothing if it does not perform at the standards for which SIG SAUER is famous. The SIG P320 RX Compact creates a superior carry handgun that excels in gunfighting—not just reactive defense, with which smaller-framed handguns are most associated. The Compact’s 3.9-inch barrel does not sacrifice ballistic performance, while its 26-ounce weight and 7.2-inch overall length also enable easy carry. Most practitioners of concealed carry employ handguns for 95% of their defensive needs, as long arms such as shotguns and rifles are not as readily accessible. The P320 RX Compact extends the effective range of the handgun beyond what most are capable with iron sights. The SIG SAUER P320 RX Compact is a valid tool offering real-world application.



Echo Valley Training Center

This article first appeared in Small Arms Review V22N5 (May 2018)
and was posted online on March 23, 2018


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