WTS OR Sig p320 compact 9mm

Oregon13 · Jul 28, 2017

I have a Sig Sauer p320 Compact with a medium size grip. It also includes a KRounds IWB holster with 1.5" belt loops. I carry the pistol on the weekends, so there is a little sheen to the front corner of the slide, but you only see it in certain light. I would consider the gun to be in great condition, not quite "like new."

The gun will come with all original packaging, a Sig Sauer OWB holster, (2) 15 round magazines, and the KRounds IWB holster. I am looking to get $425, buyer chooses transfer location and pays transfer fees.

Willing to trade towards a sig in .357sig.

Call/text at 503-807-7490 or pm me on here, I'm active daily. Portland metro area preferred.

Espire · Nov 6, 2017

if it's a compact slide, you can drop in the 357 barrel into the slide. I just picked up the 9mm to drop into my 40. Fires like a champ.
Will need the mags of course.

ArgentineSteel · Dec 21, 2017

Espire said:
if it's a compact slide, you can drop in the 357 barrel into the slide. I just picked up the 9mm to drop into my 40. Fires like a champ.
Will need the mags of course.

I know the 40 and .357 sets interchange like that, but do the 9?

Oregon13 · Dec 22, 2017

ArgentineSteel said:
I know the 40 and .357 sets interchange like that, but do the 9?

No, to do this exchange I would have to buy a caliber exchange kit from sig, which is around the price I am asking for the pistol. Sometimes it goes on sale. They send you new everything except the fire control group.

Espire · Dec 23, 2017

I had read on multiple forums (primarily the sig ones), that in the P320 compact model, if you go with the 40 S&W slide, you could drop in the 9mm barrel. The recoil spring is the same for 40/357/9, and the only thing needed was the 9 mags.

Here is what I found.

My initial setup is a 40 cal P320 in the compact version. I bought a 9mm barrel since they were on sale during black friday and decided to see if this was the case. I borrowed a 9mm magazine.

Starting with the first measurement, The 40 cal chamber (0.6590) is just shy of being 4 hundredths of an inch larger then the 9mm (0.6545)

The 40 cal barrel definitely has a larger OD on the barrel portion (as to be expected)

Both barrels fit properly in the slide when I dropped them in. I did not change out anything but the barrels (the recoil spring is the same among both calibers).

I put the 9mm on the frame, and was able to rack no issues. The 9mm mag slapped in, and I was able to rack round after round.

Now, when I decided to eject an entire magazine, this is where I found a few issues. First, the final 9mm round would not stay in (it would not chamber and drop out with the mag). I'm thinking that maybe the ejector spring may be the culprit (both calibers use the same model ejector). Where it is snug on the 40, if makes light contact on the 9mm. I believe this also caused the magazine to double feed on occasion. Until I get past this portion of testing, I will not test it at the range. I will contact Sig on Tuesday and ask them about the spring tolerance (or if I can get my hand on a 9mm compact, compare differences with measurements).

To be continued on whether a spring and a barrel swap can convert this P320 Compact 40SW to a fully functioning 9mm.

Oregon13 · Dec 23, 2017

I am looking to move to .357 sig, and hoping to use it as an excuse to move to a new platform. I was looking into Glock mostly; I thought it might be a good excuse to try a new caliber and a new gun.
Exchanging the barrels is fine, it's just not what I want to do.

Reacher120 · Dec 31, 2017

I would be interested in Sig's reply; Thinking of doing the opposite, adding .40 to an original 9mm compact.Thanks!

Espire said:
I had read on multiple forums (primarily the sig ones), that in the P320 compact model, if you go with the 40 S&W slide, you could drop in the 9mm barrel. The recoil spring is the same for 40/357/9, and the only thing needed was the 9 mags.

Here is what I found.

My initial setup is a 40 cal P320 in the compact version. I bought a 9mm barrel since they were on sale during black friday and decided to see if this was the case. I borrowed a 9mm magazine.

View attachment 415518

Starting with the first measurement, The 40 cal chamber (0.6590) is just shy of being 4 hundredths of an inch larger then the 9mm (0.6545)
View attachment 415527

The 40 cal barrel definitely has a larger OD on the barrel portion (as to be expected)
View attachment 415528

Both barrels fit properly in the slide when I dropped them in. I did not change out anything but the barrels (the recoil spring is the same among both calibers).

View attachment 415519

View attachment 415529

I put the 9mm on the frame, and was able to rack no issues. The 9mm mag slapped in, and I was able to rack round after round.
View attachment 415530

Now, when I decided to eject an entire magazine, this is where I found a few issues. First, the final 9mm round would not stay in (it would not chamber and drop out with the mag). I'm thinking that maybe the ejector spring may be the culprit (both calibers use the same model ejector). Where it is snug on the 40, if makes light contact on the 9mm. I believe this also caused the magazine to double feed on occasion. Until I get past this portion of testing, I will not test it at the range. I will contact Sig on Tuesday and ask them about the spring tolerance (or if I can get my hand on a 9mm compact, compare differences with measurements).
View attachment 415532

To be continued on whether a spring and a barrel swap can convert this P320 Compact 40SW to a fully functioning 9mm.