The Amend2 S300 P320 Grip Module

The P320 series started a revolution regarding modular firearms, well, at least for handguns. The SIG P250 started this whole FCU system, but that gun was a flop by timing. The P320 propelled it into the mainstream. SIG produces tons of different grip modules, triggers, slides, and more, but the aftermarket has also taken its turn at producing a wide aftermarket for the gun. Today we are looking at an aftermarket grip module known as the S300 grip module from Amend2.

Amend2 is mostly known for making magazines for the AR and Glock series rifles and pistols. The S300 first popped up at SHOT Show 2020, and as we all know, a few short months later, the world stopped. They planned to release the grip module in 2020, but I’m sure they ran into plenty of issues during the covid-craziness. I followed the S300 production, and as soon as Amend2 emailed me, I jumped on purchasing one.

The S300 – What It Does

I guess I’ve gotten a bit ahead of myself. The S300 is a new, aftermarket P320 grip module that allows your P320 to utilize P365 magazines. Since both guns have been extremely successful, it’s easy to see why Amend2 chose the P365 magazines. They are common, feature highly efficient capacities, and allow for a much smaller grip.

Moving between a P320 grip module to the S300 takes no time at al. Pop out the FCU, insert the FCU into the S300, and you’re done. Amend2 includes the magazine release, which is nice because swapping that back and forth is a real hassle. Once the FCU is in place, toss on your P320 slide, and you are ready to rock and roll.


Well, first and foremost, it makes your P320 easier to conceal. The S300 grip module is short and sweet and turns your P320 into a subcompact pistol frame-wise. I’m using a P320C slide, and it makes the weapon much easier to conceal, especially for IWB carry. It’s much smaller than the subcompact P320 grip module and with a longer slide that combines better ballistics, a longer sight radius, and more control with a more concealable frame.

The use of P320 magazines still allows you to maintain a decent capacity magazine. The S300 fits all the standard magazines, including the flush-fitting ten rounders for maximum concealment. I use the P365 twelve-round magazines with the MagGut +2 spring, so I get 14 rounds in a very small package.

On top of that, you can use the larger accessories you can use with the P320. For me, this includes my massive windowed SIG ROMEO1PRO mini red dot sight. The S300 has a nice Picatinny rail to accommodate weapon lights as well.

Are you worried about holsters? Don’t be. You can use all your standard P320 holsters. Well, it might have issues with light-bearing duty models and retention rigs, but this is a rig unlikely to find its way into those holsters.

Lastly, it’s surprisingly affordable. It’s only 60 bucks, and it’s made in the United States by a small American company. Not bad, plus it offers something no one else is at this time. Once someone figures out how to use Glock mags in P320s, they might be in trouble.

The S300 At The Range

Shrinking a gun’s grip makes it a little harder to hold onto, admittedly. The grip has a hanging pinky with the ten-round flush-fit magazine. With the 12 round slightly extended magazine, I have just enough room for a whole hand grip. It’s not as good as a standard P320C grip, but it’s more than useable. That’s the trade-off with a smaller gun.

The S300 grip texture is very P365 like and even matches the slightly textured magazine extension rather well. It’s good enough to keep your grip gripped without issue. A little 9mm ain’t going to dislodge your hand from the grip. I can maintain excellent accuracy, especially with an optic in place with just a slight sacrifice in control.

Your reloads might be a little slower, or at least mine are. My pinky pins in the magazine when I hit the magazine release. It doesn’t drop free unless I undo my grip a bit. Then I can commit my reload, reassume my grip, and get on target. It’s admittedly slower than dropping, reloading, and getting back at it. Again, it’s another slight compromise with a smaller gun. It’s not unique to the S300, and I have the same issue with the P365 and Hellcat.

Reliability wasn’t impacted in any way, and I went through a few hundred rounds without issue. Both the slide and grip module proved to be easy to use and provided no particular difficulty. Everything worked as it should without issue.

Making it Small

The combination of the S300 grip module and the P320C slide makes an odd-looking but effective concealed carry weapon. SIG should’ve seen the potential and tackled this themselves. I hope to see the P320 aftermarket grow in this direction and make the weapon even more modular as time passes.

Travis Pike
Travis Pike is a former Marine Machine gunner who served with 2nd Bn 2nd Marines for 5 years. He deployed in 2009 to Afghanistan and again in 2011 with the 22nd MEU(SOC) during a record setting 11 months at sea. He’s trained with the Romanian Army, the Spanish Marines, the Emirate Marines and the Afghan National Army. He serves as an NRA certified pistol instructor and teaches concealed carry classes.