P320 Frame

The grip module (aka the frame or grip frame) is Polymer for most P320's (although there is one variant I am aware of which has an aluminum grip module and one variant with a stainless steel grip module). The slide is stainless steel.

I'm new to the P320 family of pistols and there is an eye-watering number of combinations, options, etc., in how these pistols are set up. A good place to start learning about them is the Sig-Sauer web page, then read some reviews (or watch some reviews on YouTube), and then to read through the posts in this forum.

Most P320 frames are polymer. Some are reinforced with tungsten to give it heft (VTAC maybe?), but I know of no P320 frame made of SS.

Tgg said:

The frame I’d say is technically the FCU, this is the only part of the P320 that is considered a firearm.

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That makes sense; the Sig-Sauer web site refers to various models that have a polymer grip module as having a "Stainless Steel Frame" so that appears to be the "frame" of the FCU.

Hawk624 said:

What is the frame on the P320. Sig specs say it is Stainless Steel frame , Other sites call it a polymer frame.
The P320 is pretty light at 29 oz. Not that it really matters. Just purchased one that hasn’t shown up yet.

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Which model did you buy?


For the most part, the nitron & X-series of 320s use polymer grip modules. The Legion model is tungsten infused polymer & the AXG line uses Aluminum alloy.

The AXG frame on sig's website says stainless but when I called them they acted all surprised and said, no its an aluminum alloy frame. Of course, since its been brought up, I'm sure they did nothing to fix their error. Go sig.

It looks like some people are confused on the frame. I think some think the grip module is the frame. I just looked at Sig's page and to me it basically says the FCU gutted with no parts in it is the frame. And they all say stainless with different finishes on them. And the slide is stainless. The grip modules are polymer, polymer with metal mix, and aluminum. There are no polymer frames.

Agree there is confusion -- I was confused! -- about the terminology for the frame. I did a quick look up -- a lot of vendors describe the grip module as a "grip frame" or similar words. I don't think Sig itself does this (I haven't found any examples of that) but a lot of folks apparently have fallen into using a familiar term for a familiar part. But, I agree with the posts above, the "frame" as referred to by Sig, and described as stainless steel, is indeed the frame of the FCU.

Going back to the OP's post -- and it was his first on this forum -- he used the term "frame" but I think he was referring to the grip module for the P320, and for almost all intents and purposes, it is Polymer (except for the one or two models that are "tungsten infused" polymer, and the one model that is made of aluminum - the AXG).

Thanks for the clarification.

The SIG P320 owner's manual refers to the metal thing with the serial number on it as the "frame".