SIGforum
Handgun frame question

This topic can be found at:
https://sigforum.com/eve/forums/a/tpc/f/430601935/m/3380030125

June 13, 2026, 09:36 AM
Dawes
Handgun frame question
Looking at the sea of polymer-framed handguns on the market (SIG, Ruger, S&W, Glock, etc.), does everyone use essentially the same type/grade of polymer for their frames or is there a variety of polymers for this application?
June 13, 2026, 10:20 AM
Mustang-PaPa
No idea but several years ago the FN had issues with theirs going all soft and deforming around the magwells.

I sold mine after owning it a short while for other reasons.

All the other polymer guns I own seem to be hard and hold shape without issues.
June 13, 2026, 11:47 AM
SigSentry
"Glass-filled nylon" in all their proprietary composition seem to be the go-to.

I asked AI about the SP2022:

The SIG Sauer SP2022 features a frame molded from a high-durability, fiberglass-reinforced polymer composite.Like most high-end polymer-framed firearms, the underlying material is a specialized formulation of Polyamide (Nylon)—specifically engineered for chemical resistance, structural rigidity, and temperature tolerance.Key Characteristics of the SP2022's PolymerFiberglass Reinforcement: SIG Sauer infuses glass fibers directly into the polymer. This stops the frame from flexing (or "oil-canning") under heavy recoil and prevents the material from becoming brittle over time.

This message has been edited. Last edited by: SigSentry,
June 13, 2026, 12:03 PM
cslinger
At a base level yes but each one uses a “special blend” if you will. Glocks polymer is absolutely different than HKs for example.

Why and what are the differences? I dunno I’m neither in the know nor am I a materials engineer so I probably wouldn’t understand it anyway.

All I know is I have damn near 30 year old polymer pistols that are as good as the day I bought them and that’s good enough for me.


Take Care, Shoot Safe,
Chris
June 13, 2026, 01:02 PM
MacGyver
KelTec and S&W use Zytel (or at least they used to) just like Spyderco and Cold Steel do for knife handles/scales. However, Zytel is a brand name in and of itself - the company has a few different formulations of glass-filled nylon, all branded Zytel.

So I agree with those who posted above me. Glass-filled nylon is what they're all made of, but many have an exclusive formulation and/or supplier.
June 14, 2026, 01:47 PM
Fredward
Interesting about the FN. I had that problem years ago with an FN. I'd left it in the glove box in the sun and thought that I had ruined it. I posted on some forum about it and was roundly criticized because it was "impossible."
June 14, 2026, 07:13 PM
Expert308
quote:
Originally posted by cslinger:
At a base level yes but each one uses a “special blend” if you will. Glocks polymer is absolutely different than HKs for example.

Why and what are the differences? I dunno I’m neither in the know nor am I a materials engineer so I probably wouldn’t understand it anyway.

My guess is they're just different enough to avoid patent infringement problems. `Course that's just a SWAG, I'm not a materials engineer either.
June 14, 2026, 08:45 PM
Sgt 127
https://www.armoryblog.com/fir...000-snapped-in-half/

That’s the only polymer gun I’ve ever seen do that. HK seems more rigid to me than Glocks, Kahrs etc.
June 15, 2026, 06:15 AM
egregore
quote:
HK seems more rigid to me than Glocks, Kahrs etc.

If you pinch a Kahr frame with your fingers in the middle, it will bend. The front and rear portions that the slide is actually supported/runs on are rigid.