February 29, 2020
Sig P320 M18

Sig P320 M18. And P320 M17…or P320… or M18…

OK, Sig is flooding the zone here. A pistol platform that diverged from a common starting point is beginning to coalesce once more, at least from the perspective of features, if not model names.  With the Sig P320 M18, the more things change, the more they are starting to look the same.

It seems like only yesterday that the original Sig P320 was being released to great fanfare at the annual SHOT Show but it was actually 2014, yes – five full years ago. Sig Sauer crossed the Rubicon and introduced their first striker fired design departing from a legacy of legendary hammer fired pistols. Despite a few bumps along the road the Sig P320 has become a mainstay of the Sig product line and continues to evolve and expand their market.

Although the jump to a striker fired mechanism was a new direction for Sig, the other big component of the P320 M18 – its modular design, was not. Sig Sauer had already gone down that road with mixed results with the hammer fired Sig P250 line.

It’s modular.

Sig P320 Fire Control Unit
Sig P320 Fire Control Unit

If you’re not familiar, the modular design separates the fire control mechanism from the frame. Now, instead of just being able to customize the grip size through interchangeable backstraps like many manufacturers do, you can change the whole lower frame of the gun while retaining the serialized fire control unit. You can convert from full size to carry… to whatever Sig releases in that line. Flexible?  Hell yeah!

Expertise with the modular concept also enable Sig to develop the variant that won the Army’s XM17 modular handgun competition to supply the next generation of service pistols for the US military. The XM17 is replacing Beretta’s venerable M9 after more than three decades of service.

Beretta M9
Beretta M9

The Sig P320 with a number of modifications served as the basis for the XM17 design. Subsequent enhancements (post safety recall) to the P320 line share lineage with the XM17. Expanded to multiple service branches, the XM17 and XM18 (compact/carry variant) contract will eventually deliver over four hundred thousand pistols to the US military.  That’s a sweet contact for Sig.

Sig M17

To blur the lines even more, you can actually now buy a civilian version of the M17 and M18 pistols (cleverly named the Sig P320 M17 and Sig P320 M18). These new variants are almost exactly the same as their military bound brethren except for subtle differences like the M17/18 models use some secret sauce coatings on internal parts to protect them in extreme conditions.

The civvy models are otherwise dead ringers for the service models. Coyote Tan, thumb safeties, optic ready. The spittin’ image. And only in 9mm.

But I don’t want a 9mm.

Oh, a troublemaker eh? Yeah, I didn’t want a 9mm either. I have nothing against 9mm as a platform, in fact the safe is full of 9mm pistols and I shoot 9mm more than any other caliber. But in this case, well… I was feeling it for a .45.

If you want the “military” variant Sig P320-M17 or P320-18, sorry – you’re out of luck. Sig Sauer does not (at least not yet) make these in any caliber other than 9mm.

And oh, remember that modular concept? Well Sig P320s can convert between different calibers as well as different frame sizes! You can convert a 9mm to .40, or to .357 Sig… or to…  Wait, that’s it. No, you can’t convert from a 9mm to a .45ACP.  If you want a .45ACP, you have to buy a .45ACP. At least that’s the way it is today.

So we got the Sig P320 .45ACP Compact

Sig P320C .45

OK, so it is not a military clone, it is not Coyote Tan and it is not optic ready. It is however, .45ACP and it is exactly what I wanted to shoot. Our pistol sports the perfect Sig Nitron black finish and is the variant that includes the manual thumb safety (something you’ll find on the M17/M18 but not on the generic non-MA P320 models).

This particular pistol was an original model that has been returned to and from the factory under the Sig safety recall. If you live in a cave and haven’t heard about that, here’s the Cliff Notes version: If dropped in exactly the right way the original Sig P320 mechanics were light enough that the gun could discharge, essentially causing a phantom trigger pull from the inertia alone. That would be, well… bad.

Sig P320 Recall Upgrade

Sig addressed this under recall by replacing and modifying parts to prevent this from happening. The updated pistol has a new lighter trigger, striker, sear and a little machine work. These modifications are now integrated into all new Sig P320 models being shipped.

The compact frame model fits my hand great and points very naturally. It is a solid feeling pistol and after recently spending much time with its smaller sibling, the Sig P365 micro-compact, the 26 ounce gun has a reassuring heft to it. There are no shakes or rattles here. This gun is what you call, “tight”.

Sig P365 and P320
Sig P365 and P320

The Sig P320 comes with SIGLITE Tritium night sights and two (9) round steel magazines of typical excellent Sig quality. The night sights present well in very dimly lit conditions but I’d prefer a hybrid fiber optic to brighten up the front sight in daylight. The SIGLITE dots are pretty much lost in the day but there is more than adequate daylight between the sight posts to give you a good picture.

The grip tapers nicely between your thumb and index finger and directs the web of your thumb tight against the frame beavertail.  The reversible mag release protrudes enough that someone with stubby digits like me can drop a magazine without altering their grip and that’s a plus. By the way, the Sig P320 magazines drop free without a hint of resistance.

The Sig P320 Compact features a standard Picatinny accessory rail (unlike the proprietary rail on the little P365). The ambidextrous thumb safety engages and dis-engages with a positive click and is big enough to move with intent but not so big it’s in the way.  Not a manual safety fan? Standard P320 models don’t have them so you have a choice. If you want the P320-M17 or M18, you’re stuck with them.

Sig P320 Full Size Rail

The grip is textured on the sides, front and back. It’s not as aggressive as the little P365’s texture but it is effective enough. Takedown is a breeze. Clear it, lock back the slide, rotate the takedown lever and remove the slide. The takedown lever has a few grooves on it to assist your thumb’s grip but it still takes a firm push. But simple? Definitely.

Then there’s the trigger.

Ok, we saved the best for last. The trigger is good. Damn good. When Sig went back and redesigned the trigger and firing components to enhance safety, a good trigger got even better. There is about 1/8” of take up then another 1/8” of smooth compression before the trigger breaks. Positive reset and do it again. It all happens in that very economical ¼’ or so of travel. My Lyman gauge showed an average pull weight of 5 lbs., 7 oz. but I actually thought it would be less as there’s just no grunge or stacking.

It feels great. And because the trigger behaves the way a trigger should, it is easier to put rounds where they should be – in the center of the target.

Sig P320 .45 Target

The Sig P320 made me look like a good shot right out of the box. Certainly better than I am. I shot two magazines just to get familiar with the feel and then printed this at 10 yards. Me likey. The .45 does have a bit of push vs. the pop of my 9mm mouse guns but the weight of the P320 keeps the recoil in check and getting back on target is quick.

Does it make a good carry gun?  For accuracy and reliability, I say yes.  But I’m on the fence here with the compact grip frame for concealability.  If you’re a bigger person, yes you could. There’s a lot of folks, not all big, who carry bulkier pistols than this with no problem. I’m really liking this pistol and the way it shoots but for me it may be just a little tough to conceal. At almost 1 ½” wide and nearly two pounds loaded it’s not going to just “disappear”. 

The “carry” frame configuration may be a better CCW option and that’s the beauty of a modular pistol right? Well, sort of. Like the Sig P320 line in general, more choices can make things slightly complicated. If you go with a standard 9mm P320 you can easily drop down to a carry frame with different grip sizes. Perfect. But a .45ACP with a safety? It seems there’s no “carry” frame option there.

I guess I’ll just have to experiment with holsters and make it work.  Maybe a Miami Vice shoulder rig? Linen jacket? Nah, I’d never pull it off.

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