Firing pin stop hammer contact angle

[TheOtherErik]

I've read where that the angle of the firing pin stop on the leading edge were it contacts the hammer will effect the unlock time. A sharper curve will slow the inital movement of the slide keeping it locked a bit longer. My firing pinstop in my STI open gun has a long wide curve to it. I belive this is the cause of the fire ball from my ejection port and the heavy build up of soot inside the front of the slide where the barrel holes are. How tight should I make the curve? or no curve at all- straight 90* angle on the leading edge. what kind of angles are you guys running in your STI/SV firing pin stops. Pics would help. Would an EGW o/s or similar fiing pin stop have some kind of angle on the leading edge? Thanks for any insight.

got pics now. the one on the left came out of my limited gun factory STI edge. the one on the right came out of my custom built Open Gun w/ a STI slide

pin stop picture

Edited September 7, 2004 by TheOtherErik

[Brazos Custom]

If you want to experiment you need to get the EGW part. It has a 90 degree angle to start. There is not much you can do with the stock STI/SV firing pin stop. You can leave the EGW stop at 90 degrees or put whatever angle on it you want.

[shred]

Btw, leaving the EGW OS stop squared off isn't good for the long-term continued roundness of your hammer pin holes. I shot one like that for a while in the 175 PF days, but have since gone to a gentler curve for smoother slide action.

[TheOtherErik]

OK i got the picture up. I figgure that the new firing pin stop should probably take the shape of my limited one or maybe even less of an angle to start. Erik Warren if your around, what does your firing pin stop look like, our guns were built by the same smith.

[ErikW]

Dan built my guns with a radius on each. Not sure if it's a constant or increasing radius... not sure if they are stock parts or not. I'm pretty sure they are stock parts, probably STI contingency parts. They look like the one on the right in your picture.

BrianH put a new slide with EGW stop on my backup Limited gun and it has a similar radius.

Maybe you should try a mainspring of increased power.

[mcoliver]

My gun isn't close to an S_I, but I started with an EGW square stop. My final radius is very similar to the left one in your pic but more rounded. I used to have primer tear marks while using something similar to the right on your pic. Mainspring is 15#.

[wadrew]

I use a long continuous raduis type slide stop on all my blasters....

I tried the short radius and the 45 drgree angle types, and the longer smoother radius type causes less dwell in the slide action. I have noticed less muzzle rise (flatter shooting) with this type. The 45 degree one let my muzzle flip up more before the slide came back, causing a 'bouncier' recoil. I usually polish my FP stop and stone the disconnector rail (white india stone then white ceramic ruby stone), then I polish the contacted areas on the hammer that are contacted by the FP stop and the 'disco' rail on the slide. The result was a flatter shooting gun with a smoother action then the hammer is in contact with the FP stop and disco rail.