Sig 320 Modularity

Roland Thunder

New member
I was at the range last night and someone let me borrow a Sig 320 9mm. I sure liked the way it shot. I already have a Sig 320 45acp FS, which I like a lot. It just occurred to me that with the modularity of the 320, I should be able to convert it to a 9mm, right? I am not sure what size the FS will convert down to. I think you can convert a FS to the Carry size but I'm not sure you can convert a FS to the compact size, at least by just purchasing another frame.

Correct me if I am wrong.

So, I guess my real question is "Can I convert the 320 45acp FS to a 9mm Carry or Compact size and if so, what is involved
 
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As far as I understand the .45 parts are not compatible with everything else... 9 to 40 and all the sizes can be converted with the right parts.

The thing that I like is that you can put a sub compact (and a carry I think) frame on a compact barrel and slide....
 
I apologize for answering a question not asked, but it's the closest I can come. I know that grips and mags interchange between the P320 & the P250, and I have the P250.

My trigger assembly (serialized component) works on the three grip/slide sets I have:
full sized .45acp, compact 9mm, & subcompact 9mm. The same should be true of the P320

I also checked the SIG website, and their P320 pages don't indicate that there is more than one trigger assembly size. So your trigger assembly should work with all available grip sizes. I'm sure someone with a P320 will be along shortly to confirm or disprove.
 
You cannot go from 45 ACP to other calibers in the P320 series guns. The fire control striker mech will not fit. You can put it into other 45 ACP sized P320 frames i.e. sub compact, compact or full sized.
 
I believe the original intent was to be able to go from 9 up to 45, but they couldn't get things to play right, so they limited it, keeping the 45 version separate.
 
WVSig said:
You cannot go from 45 ACP to other calibers in the P320 series guns. The fire control striker mech will not fit. You can put it into other 45 ACP sized P320 frames i.e. sub compact, compact or full sized.

WV:
What would I need to purchase (besides the frame) to convert my Fullsize 320 45 to compact or carry size
 
The X-Change Kits for the P320 are expensive. Even a little more than the P250. The kit for the 45 is hard to come by because the 45 just came out last year. Expect to pay over $300 if you find one.

I have 2 of the P250 kits and they were $250 for one and $300 for the other. Could have done it for ~$200 for 2 calibers 357 Sig and 9mm with a Glock 22.
 
Carry is short slide and long grip so yeah, there's pretty much no way to go from FS to carry - cheaper to buy a new gun. But you can get a compact frame and shorter mag to go on your long slide.
 
"It's complicated."

The P320 has different FCUs for the 45 and 9/357/40, while the P250 has a single FCU for 22/9/357/40/45.

Both the P320 and P250 have 45 grip modules that are different from the 9/357/40 grip modules.

Any size (FS/C/SC) slide will technically work on any size (FS/Ca/C/SC) grip module.

I'm not sure I would trust a FS slide on a SC grip (photo); the gap between the bottom of the slide and the grip module's dust cover would bother me.

While smaller slides will work on larger grip modules (photo), they serve no purpose, look strange, and good luck finding a holster.

Some people actually prefer slides one size larger than grip modules, such as FS on Compact or Compact on Subcompact (photo).
 
You need a slide, barrel and frame kit. They are hard to come by.
And expensive. SIG (and everyone else) has made a big deal of the modularity but IMO the price and availability of the conversion parts is such that the modularity has almost no practical value.
 
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