STI hybrid with loose firing pin stop

abruzzi · December 20, 1999, 11:17 PM

I have an STI hybrid pistol chambered for 357 sig which has had almost no rounds run thru it. I have encountered a problem where the firing pin stop comes loose and drops down to block the hammer from striking the firing pin. And if I fiddle with it, the firing pin comes flying back at me.

Some guys have suggested just to keep shooting until the gun loosens up(?). Others have suggested getting a stronger spring on the firing pin to increase pressure against the stop.

Any thoughts out there?? Thanks.

James K · December 20, 1999, 11:27 PM

Loosens up? At least one part is already too loose (wasn't he a French painter?).

You might try a new firing pin spring, and that might work.

If it does not, you will need to stake the stop in place or get an oversized one and make it a tight fit.

That problem is not usually understood. It is complex and several things involving Mr. Newton's laws are going on at the same time.

Jim

Mikey · December 20, 1999, 11:28 PM

There is definitely something wrong!

Either the firing pin spring is waaaay to soft or the firing pin is sticking in the hole while in it's forward position during firing. Either way, have a smith look at it right away. If the pin is sticking you could possibly go full auto when you least expect it!

Mikey

December 20, 1999, 11:17 PM	#1
abruzzi Senior Member Join Date: April 23, 1999 Location: Hurricane, WV, USA Posts: 192	I have an STI hybrid pistol chambered for 357 sig which has had almost no rounds run thru it. I have encountered a problem where the firing pin stop comes loose and drops down to block the hammer from striking the firing pin. And if I fiddle with it, the firing pin comes flying back at me. Some guys have suggested just to keep shooting until the gun loosens up(?). Others have suggested getting a stronger spring on the firing pin to increase pressure against the stop. Any thoughts out there?? Thanks.

December 20, 1999, 11:27 PM	#2
James K Member In Memoriam Join Date: March 17, 1999 Posts: 24,383	Loosens up? At least one part is already too loose (wasn't he a French painter?). You might try a new firing pin spring, and that might work. If it does not, you will need to stake the stop in place or get an oversized one and make it a tight fit. That problem is not usually understood. It is complex and several things involving Mr. Newton's laws are going on at the same time. Jim

December 20, 1999, 11:28 PM	#3
Mikey Senior Member Join Date: November 14, 1998 Location: Tennessee Posts: 885	There is definitely something wrong! Either the firing pin spring is waaaay to soft or the firing pin is sticking in the hole while in it's forward position during firing. Either way, have a smith look at it right away. If the pin is sticking you could possibly go full auto when you least expect it! Mikey