SIGforum
New to me P320 .40 S&W converting to .357 Sig.
December 05, 2025, 11:18 PM
Raven87New to me P320 .40 S&W converting to .357 Sig.
I picked up a nice P320 Full Size at local pawn shop today. It doesn’t look like it’s ever been fired. It’s a .40 and I just bought a .357 Sig Barrel that will be here next week to set it up in that caliber.
Any advice on the conversion? Anyone with experiences shooting the .357 Sig in a P320?
From what I’ve read it’s just a barrel swap. I only paid $389 plus tax so I think it’s a decent buy.
(I would post some pics but I’m not sure the best way to do that yet.)
December 06, 2025, 04:52 AM
RichardCPractice your best possum-eatin-it grin before the first range day.
December 06, 2025, 06:47 AM
Raven87Will do!
December 06, 2025, 10:00 AM
sigfreundI have some experience with various models and configurations of P320s in 357 SIG and 40 S&W. I’m often lazy and just use a 9mm model for most training, partially because of ammunition considerations, but every now and then I’ll break out one in 357 or 40.
Because both 357 and 40 are significantly more powerful (and, of course, more ballistically effective), shooting them obviously feels different than 9mm Luger. What I always find, though, is that after the first magazine or two, I no longer notice the difference to any significant degree—even with my nearly 80-YO hands and wrists (arthritis mostly affects my fingers). I shoot more 40 than 357 even though I prefer the latter because 40 ammo is more available and there is no discernable performance difference when shooting the two. And yes, it is only a barrel swap to switch between 357 and 40.
I just acquired a 357/40 slide that I mounted an Aimpoint ACRO optical sight on, so I plan to use those cartridges somewhat more in the future.
My primary carry gun is a P320 “Carry” model in 357 SIG. When I was a member of an LE team, my pistol was a full size in the same chambering; it’s one of my “house” guns now.
I have fired 937 rounds of 357 SIG and 6045 rounds of 40 S&W ammunition with various P320 pistols.
► 6.0/94.0
“I can’t give you brains, but I can give you a diploma.”
— The Wizard of Oz December 06, 2025, 10:51 AM
P250UA5My P320 started as a 9mm
Swapped top ends and mags with a member here for 357Sig
It's a hoot to shoot & usually turned a head or two at an indoor range.
Swapped back into a 9mm, mostly due to ammo costs and lack of local stock in 357Sig.
The Enemy's gate is down. December 06, 2025, 11:12 AM
Raven87I definitely agree that the ammo cost is a concern as well as availability of the 357 Sigg ammo. I would like to get a slide with the nomenclature of 357 on it – are they readily available?
Thanks for the replies!
December 06, 2025, 12:00 PM
sigfreundThere is a post in the Bang Bang Boutique section about the availability of some 357 SIG FMJ ammunition. To my knowledge, Speer Lawman is as good as it gets.
I have never seen cartridge identification markings on P320 slides. The 357/40 slide I purchased from SIG recently does not have any. Cartridge markings are on the barrels.
I tell the difference between 9mm and 357/40 slides by looking at the undersides. The 9mm slides have lightening cuts at the left rear (right rear if the slide is upside down).
► 6.0/94.0
“I can’t give you brains, but I can give you a diploma.”
— The Wizard of Oz December 10, 2025, 06:52 PM
colbuckyI had purchased a 357 SIG exchange kit a few years ago,very accurate and never had a problem
December 10, 2025, 07:25 PM
sigfreundquote:
Originally posted by Raven87:
I can’t figure it out. I’m using photobucket but this isn’t cooperating. Suggestions?
Did you see the discussion in this thread?
https://sigforum.com/eve/forum...0601935/m/6470098434
► 6.0/94.0
“I can’t give you brains, but I can give you a diploma.”
— The Wizard of Oz December 10, 2025, 08:58 PM
Raven87No I had not but thank you! That’s exactly what I needed. I have use PB in the past but could not figure how to make it work now.
Flickr it is. Thanks again!
December 10, 2025, 09:38 PM
Raven87
December 10, 2025, 09:45 PM
Raven87
December 10, 2025, 09:49 PM
Raven87
December 10, 2025, 09:51 PM
Raven87
December 10, 2025, 09:58 PM
Raven87Thank for the help! I’ve got it going now.
December 10, 2025, 10:55 PM
Raven87
December 11, 2025, 06:27 AM
jgerge222Very refreshing to see members posting positive info and results about the P320 ! My P320 Compact in .357 Sig accompanies me almost every day.
December 11, 2025, 08:34 AM
Raven87I agree about the P320. I have six of them and enjoy shooting every single one, including my two X-Ten’s.
Great guns.
December 13, 2025, 02:33 PM
Raven87I took it to the range today and it ran perfectly with the Federal ammo I brought along. No issues at all.
I’m really happy with it.