Originally Posted by gunner500
Sounds complicated with the revolver bit, been wondering where my 40's would head space in the 10 chamber after reading Sarges suggestion.


Don't do that with your 1911! It is OK in Glocks but is not safe in most other pistol platforms, including the 1911. The difference is in the firing pin/striker, and how far it can extend out of the breech face.
In a 1911, if a 40 S&W round jumps ahead of the striker in a 10mm chamber, the firing pin can still reach the primer. On ignition, that case gets slammed back past the extractor and into the breech face, and the primer may or may not get there first. I haven't seen a case actually blow out from this, but have seen them look pretty bad. The one pictured below is a good example. If you want to shoot 40 S&W for practice in that nice new 1911, you'll need a dedicated 40 S&W barrel to be safe.

In a Glock on the other hand, if a round jumps in front of the extractor (which I've never seen happen in my 10mm Glock BTW), the striker can't reach the primer, so the round just doesn't go off. There's no danger in blowing up the gun there, just a click. Some prefer to swap in a 40 S&W barrel anyway to be safe, but you don't have to in a Glock.

Note the missing chunk of the rim that was sheared off when getting pushed backwards into the extractor...
[Linked Image]

This shows maximum firing pin protrusion on a 1911 vs Glock. Note position of the pin tip relative to where a case would rest in front of the extractor.
[Linked Image]

Last edited by Yondering; 05/06/17.