Glock Magazine? .40 to .357 SIG

**JB70** · February 26th, 2011, 10:59 PM

Is the casing the same size on the 357 SIG and 40 SW? Can you use the 40 magazine to feed the 357 SIG?

**Arrdy** · February 26th, 2011, 11:53 PM

From what I understand, the .357 sig is based on a .40 S&W case. The .40 S&W Glock mag will feed .357 Sig.

**F16vipers** · February 27th, 2011, 12:21 AM

Don't have personal experience converting 40-357 but I've done some research on the topic. The 40 mags should feed the .357 but may not do so reliably. The recommendation is to buy a .357 mag if you do a conversion because there is a slight difference between the mags.

**39flathead** · February 27th, 2011, 01:14 AM

The only difference between the .40 mags and the .357 mags are that one is marked .40 and the other is marked .357, they are the same and will interchange.
They use the same follower, there will be no feeding problems.

**Waldershrek** · February 27th, 2011, 10:01 AM

Load them up and go to town!

**Edg** · February 27th, 2011, 10:17 AM

They are the same on a Sig, assume they would be on a Glock too.

**bripro** · February 27th, 2011, 10:38 AM

I was told by Glock c/s that the follower on the 357 is at a different angle than the .40. LWD lists both followers with differert part numbers as well. I have also been told it is not necessary to change a thing except the barrel. My M&P40 mags are marked .40/357 so I would think you should be fine.