Looking at mag carriers, I noticed that, of the makers that list P320 mags, many, if not most of them have selections for the frame size (i.e.: full vs. compact vs. ...), but not the caliber. This implies to me that all P320 full-size magazines have the same external dimensions. Do they?

As the grip modules are all the same for 9mm/.357/.40, I can only assume the mag bodies are the same dimensions. I would expect follower and feed lip differences, but that wouldn't affect mag pouches/holsters.

I believe they are all the same in dimension, just differ in length and capacity.

Well, even Sig CS wasn't certain. Said the .45 ACP mags were a bit different from the 9/40/357 mags, because of a difference in the .45 ACP grip frame module, but wasn't certain on the overall outer dimensions.

She's going to reach out to somebody in one of their product groups to get a definitive answer.

In the meantime, I guess I'll check with my favourite local fun store to see if they have any 9/40/357 full-size in stock and, if they do, head on over there with one of my .45 ACP mags and my digital calliper.

Ensigmatic, I'm going off of a 227 mag and an undifferentiated 250/320 mag for the .40/357. I'm also using a tape measure, so this may not be the most precise data you can get.

The length down the backs of the magazine are the same at about 4.75". The width of the mag bodies from back to front differs - the 40/357 measures a little under one and a quarter inches, where the 227 mag measures out to about one and three eighths. The width across the front of the mags slightly different as well - seven eighths of an inch for the 40/357, fifteen sixteenths for the 227. As near as I can tell, both magazines lean forward at the same angle.

Lemme know if you need me to get out the calipers, or want the mags measured a particular way.

Thanks for the info, Il Cattivo.

I'm guessing the assumption here is that P227 mags are the same as P250 .45 ACP mags are the same as P320 FS .45 ACP mags?

I'll take a calliper to one of mine and see how close I come to what you measured with the P227 mag.

If it wouldn't be too much trouble: Yes, precise side-to-side and front-to-back measurements of a .40/.357 mag would be appreciated.

I got a response from Sig CS, already, and it's kind of weird. One of their engineers responded to the CS rep with "that information is kept proprietary." "Proprietry???" Uhm...

The P320 .45 ACP magazines are slightly larger than the 9 mm Luger P320 magazines. Since the 9 mm, .40 S&W, and 357 SIG P320 magazines all have to fit into the same fire control unit, I am assuming that they have the same external dimensions.

I have magazines for a full-size P320 .45 and magazines for compact and subcompact 9 mm P320s. Obviously, the 9 mm Luger magazines taper down to a narrower size at the open end, and have a narrower follower for the narrower 9 mm cartridge. Measuring with a caliper below the taper, the 9 mm magazines measure .852" in width at the widest part of the magazine tube. The .45 ACP magazines measure .926" in width at the same point.

The .45 ACP magazine tubes are also larger in the anterior-posterior (front to back) dimension. The 9 mm measures 1.267" and the .45 ACP measures 1.365". The external dimensions of the magazine base pads are very nearly the same but the .45 ACP pads are very slightly wider and a little less than .05" longer in the front to back dimension.

I can't compare lengths of the magazine tubes since my .45 ACP mags are for the full-size and my 9 mm mags for the compact and subcompact.

quote:

I'm guessing the assumption here is that P227 mags are the same as P250 .45 ACP mags are the same as P320 FS .45 ACP mags?

Yes, the 250/320 .45 mags are the same as the 227 mags. Lemme dig out some calipers.

ETA:

Both mags are about the same heighth; depending on how you measure the 40/357 mag is a couple of hundredths of an inch taller. Both base plates on the mags I'm measuring seem to be identical. If you'd like the heighth measured a particular way, let me know.

Measuring the width of the mag body across the back, the .45 mag is .055" wider than the 40/357 mag (.895" vs .840"). There's a slightly larger difference when measuring width across the front of the mags; .900" for the 45 vs .840" for the 40/357.

Measuring from front to back, the .45 mag is 1.355" wide, vs. 1.25" for the 40/357 mag. The width from front to back was measured by squaring one side of the calipers against the flat back of the mag body and closing the other side onto the front of the mag body so that the calipers were perpendicular to the mag body.

This message has been edited. Last edited by: Il Cattivo,

Thanks for the measurements, guys!

While I was out I stopped by my favourite fun store, where they had a P320 9mm FS in stock.

Here's what I measured:

9mm

Front-to-back: 1.26+
Side-to-side: 0.85+
Height: ±4.7

.45 ACP

Front-to-back: 1.36+
Side-to-side: 0.93+
Height: ±4.7

Interesting that my measurements appear to have come closer to pblanc's than they do to Il Cattivo's.

Yeah, I kinda wonder if/how we measured differently. OTOH, we seem to have a 0.01" difference in the front-to-back measurements.