Sig Sauer’s first striker-fired pistol, the P320, features a modular grip frame, a removable fire-control assembly and slide, barrel and caliber interchangeability. Shown with a Crimson TraceCMR-203 Rail Master.
The P320 offers a high bore axis for enhanced control while firing, and the beavertail helps prevent “slide bite.”
The P320 lacks an external hammer, and it includes typical Sig Sauer features, including high-visibility front and rear SIGLITE night sights. The slide has a matte black Nitron finish that enhances the pistol’s durability and makes it ready for harsh extremes.
The slide’s edges have been rounded for a smooth, snag-free draw. Also note the P320’s large ejection port.
Sig designed the grip frame with cutouts on both sides of the mag well to make it easier to remove the 17-round magazines.
Listening to requests from law enforcement agencies, Sig designed the P320 so it’s easy to take the pistol down without having to pull the trigger.
The author tested the P320 Full-Size with a 4.7-inch-long 9mm barrel. Sig Sauer designed the platform so it can easily accomodate .40 S&W and .45 ACP barrels as well. Carry models of the P320 have 3.9-inch barrels and shorters slides to match.
The pistol has front and rear slide serrations that offer users ample traction for performing slide manipulations. Also note the relatively short trigger reach as well as the easy-to-use takedown lever and slide release.
A generous amount of Picatinny rail is molded into the dust cover for mounting accessories like lights or lasers.
Sig Sauer offers the P320 with or without (shown) a trigger safety toggle installed within the trigger. Also note the triggerguard’s front serrations.
The pistol comes with a polymer belt holster that fits the P320 well. The author used it to demonstrate properly drawing and firing while teaching a MAG-40 class.
In front of dozens of students in an Illinois MAG-40 class, the author shot a perfect 300 score in a demonstration qualification course with a stock P320.
The P320 ran flawlessly with all of the test ammo. At 25 yards, it produced this best five-shot group measuring 1.15 inches with Sig’s 124-grain Elite Performance ammo.
The striker-fired P320 offers the speed and accuracy today’s shooters need. Here the author fires rapidly on the range. Note the three casings in the air while he’s still on target.
I first saw the P320, Sig Sauer’s first striker-fired pistol, in the summer of 2013. I had known for some time that Sig had been working on a striker-fired version of its double-action-only P250 with a shorter trigger and based on police demand. The P250 was a logical starting point instead of the proverbial “new sheet of paper” because it could incorporate that gun’s incredible versatility. By simply purchasing spare parts, the user could convert the gun from a full-sized pistol to a compact concealed carry model, and swap calibers, with ease. Other makes offered adjustability as to hand size, but this capability would take the new gun considerably farther in the versatility department. It would also fit existing holsters and accept existing magazines for the P250, an advantage for any newly introduced handgun.
Designated the P320, it was originally announced in calibers 9mm, .40 S&W and .357 SIG, with .45 ACP to follow. A manual thumb safety and a Glock-like trigger safety tab would be optional. I recently received a Full-Size model in 9mm with SIGLITE night sights, two 17-round steel magazines, no thumb safety or trigger tab, and a polymer hip scabbard.
The first thing I discovered about the P320 was that it has a “stand-off capability,” a good thing. This means that if the muzzle is pressed hard against a firmly resisting surface (like the chest of a murderer about to kill you) it will fire, instead of going out of battery and failing to discharge, as most autopistols will. It amazes me that more people don’t test for this, and amazes me still more that manufacturers who put this potentially life-saving feature into their autopistols don’t advertise it.
The serialized part of the P320 is what Sig calls the Fire Control Unit, or FCU. The design will allow for a range of trigger pulls, from 5.5 to 7.5 pounds in weight, by changing parts. My test gun came from the factory with a pull that felt to me like a Glock with a standard trigger spring and an 8-pound connector, but with somewhat less take-up. My Lyman digital trigger pull gauge confirmed this. Since this pistol has a pivoting trigger, leverage comes into play, and the pull weight changes depending on where you measure it on the trigger. The very bottom, the “toe” of the trigger, yielded an average pull weight of 6.2 pounds. Measured from the center of the trigger, where most index fingers rest, it came to 8.74 pounds. This added weight seemed reassuring.
There are three things to address on field-stripping the P320: (1) It is easy; (2) Like most of the Sig Sauer pistols that preceded it, the P320 comes apart in two pieces, making it easy for us instructors to demonstrate things best seen from the front without pointing a functional firearm in the wrong direction; (3) You don’t have to pull the trigger to disassemble the P320. Some careless people have shot themselves and others with pistols requiring a pull of the trigger to initiate the takedown process. I have never personally held this against the gun designs or makers involved. Anyone stupid enough to point a gun at themselves or someone they have no right to harm and pull the trigger has exhibited an overwhelming level of negligence. At the same time, some police departments have seen this happen and insist on guns that don’t work that way. So, the P320 follows Sig design doctrine that the gun won’t disassemble unless the magazine is out and the slide is locked open.
“Pointability” is obviously a highly subjective factor, but none of the many on my test team who handled and shot the 9mm P320 pistol had any problem with it in that regard.
I tested the P320 at 25 yards from an MTM pistol rest on a concrete bench. I used three brands of ammunition with velocities more than 500 fps apart and bullet weights spanning a 52-grain weight range. Each five-shot group was measured once for all the hits, and again for the best three, the latter measurement having proven over the years that it will come very close to what the same gun/load combination will deliver for all five shots from a machine rest. Most shooters can shoot from a benchrest a whole lot more easily and less expensively than setting up a Ransom machine rest, and this lets more readers see how close their own gun comes to the one the gun writer tested. All groups were measured from furthest shot to furthest shot, center to center of the bullet holes, to the nearest 0.05 inches.
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For a light and fast load, I ran Buffalo Bore’s TAC-XP using a 95-grain, all-copper Barnes hollow point loaded to a nominal velocity of an impressive 1,550 fps. Yes, this is a +P+ load. A 6 o’clock hold on a small Caldwell Orange Peel bullseye put three shots in the center ring and a couple high. The five-shot group measured 3.15 inches, and the best three clustered into 1.65 inches.
On the other end of the spectrum were the popular 147-grain Winchester FMJs. At sanctioned IDPA matches where all ammo is chronographed, this load has generally done a bit over 1,000 fps out of my 4.5-inch-barreled Glock 17. From the P320, this ammunition grouped five shots into 3.95 inches, centered a bit to the left with four in the black. The best three of those were in a more promising 2.05 inches. I’ve seen several other polymer pistols do worse.
The middle ground for currently available bullet weights proved to do the best in this particular P320, interestingly enough with Sig’s own recently introduced brand. The Sig V-Crown is a jacketed hollow point with a pre-stressed jacket to aid expansion and, for the same purpose, a wide mouth that tapers in cross-section to the “V” that gives it its name, finishing with a tiny hole at the bottom of the “crater.” This load was the most precise in both group measurements, yielding a 2.45-inch spread for all five hits and 1.15 inches for the best three. The group was centered a bit high on the bull, with all five shots in the black.
The vicissitudes of scheduling didn’t allow me to shoot a match with the test P320, but I did teach a MAG-40 class with it at the Illinois State Rifle Association range in Kankakee, Illinois, in the summer of 2014. The polymer scabbard furnished by Sig worked fine on the range but was not especially concealable, so for concealed carry I used an inside-the-waistband holster made by Elmer MacEvoy of Leather Arsenal in Middleton, Idaho. Cut originally for a Sig P250 in the same barrel/slide configuration, it was a perfect fit for the P320 Full-Size.
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At the end of each class, the staff runs a “pace-setter” drill. That is, we shoot the same course the students are about to shoot to qualify, with the students watching. It goes to an adult education principle called “modeling.” If people have to perform a skill test under time, they do it better if they’ve just seen someone do what’s going to be expected of them momentarily.
I shot it with the P320, the Sig holster and 9mm ball ammunition. Having only two magazines, I loaded one with six rounds and one with 12 rounds for stages requiring two reloads; this particular course of fire is revolver neutral and shot in six-shot strings, and that allowed a tactical reload for 18-shot stages.
Some have speculated that the P320’s bore axis might be high enough to increase muzzle jump in rapid fire. I did not find it so. Grasping the pistol with a thumbs-down hold, I never overrode the slide release. The pistol functioned perfectly. Having spent many years with Glock pistols fitted with standard-weight connectors and NY-1 trigger springs, an 8-pound pull on a polymer-framed pistol was nothing new. Every shot broke fairly cleanly. If anything, it forced me to hold harder and maintain control. I finished, not with as tight a group as I’d have liked, but still with a solid 300 out of 300.
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That saved me some money, because my deal with the class is if they tie my score, they get an autographed dollar bill, and if they beat me, an autographed five. Counting staff, that could have been a couple hundred bucks if I’d gone in the tank. Instead, I wound up only dispensing a few singles—always a pleasure—and one five, for which I confess mixed feelings. Fellow instructor Bob Houzenga’s 300-point score had a group tighter than mine by about 0.75 inches, and that won the tie-breaker. Bob is a former six-time national champ in various shooting disciplines; losing to him on a tie-breaker is an ego-builder, not something that will send you to Dr. Phil for therapy. Overall, the P320 had allowed an old geezer on the downside of his shooting career to give a decent account of himself, and the guy behind that P320 had no complaints at all.
In a long day of concealed carry, the Leather Arsenal holster held the big P320 at enough of a forward tilt behind the strong-side hip that it didn’t bulge at all under an un-tucked shirt or a photographer’s vest. There were no sharp edges; carrying the P320 was perfectly comfortable. For those with tighter dress codes who need a smaller gun, well, that’s where the modularity of the P320 and its convertibility from full to compact sizes comes into its own, right?
In a month of testing on the road that encompassed several hundred rounds in four states, the P320 never jammed once, no matter who shot it—men and women, lefties and righties, five-foot-tall folks and those who were taller. People who shot it with straight thumbs overrode the slide stop and kept the gun from locking open when it ran dry, but that’s a human factor, not a mechanical malfunction. A design failure? Well, if you know the slide stop is located where it is and choose to shoot in a fashion where your thumb holds a lever down and keeps it from performing its job, it seems to me more like “incompatibility” than “failure.”
In a round count approaching 1,000 with no cleaning and so many shooters I lost count, there were no mechanical failures of any kind. There was one misfire with a reloaded cartridge whose primer showed a deep and well-centered indent; I blame that on the round, not the pistol.
The bottom line is, the choice of striker-fired, polymer-framed defensive pistols just got wider, and I thank Sig Sauer for that. The P320 gives a new dimension to modularity, which will be particularly important to those who live in four-season climates, and/or in jurisdictions where only one specific serial-numbered pistol is authorized on their permit to carry.
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