Thursday, March 08, 2007

1911 firing pin stop modification

A while back I was browsing through the 'Handguns: Autoloaders' forum at The High Road and found mention of a change to the firing pin stop on a 1911 that was said to make a big difference in felt recoil. So I dug around some more, which led me to the M1911.Org site. Which led me to the gunsmithing sticky threads, this one in particular.

This sounded interesting, especially since my hands sometimes bother me after a box or so through mine. So I went to Brownells and ordered two of these EGW stops.

If you're not familiar with the 1911, the firing pin stop fits into a slot in the back of the slide





















and holds the firing pin(center) and the extractor(circular piece on the right) in place. The bottom of it

















on the factory piece has a nice, round curve; this is where, as the slide moves back, it cams the hammer back to cock it. The idea is that if you take a stop like the EGW which is square on the bottom,

















fit it to the slot of the pistol and then give it just a slight bevel at the bottom edge














it changes some things. When the slide moves back under recoil, the factory stop makes the camming action a smooth operation that doesn't take much energy away from the slide; but if you give it a much smaller bevel like this- from what I've read the way John Browning originally designed it- it takes more of the energy the slide carries to cam the hammer back, which slows the slide down, which changes the way the energy moves around with- I read- some good changes.

These stops are made oversize so they can be fitted to your pistol. This one was a touch too thick, so I stoned a bit off the back. Then I started stoning the sides to narrow it a bit. Lock it in a padded vise, cut a bit, flip it over and cut the same number of strokes on the other side, try. Black the shiny area(I used Sharpie) and repeat until you get a good fit.

For the bevel, I'd suggest reading that thread at M1911 for specifics. Basically, cut a very small 45-degree angle with a fine file, and it HAS to be same angle and width across the face, otherwise it'll cause some nasty twisting(torsional?) stress to the hammer and hammer pin. I then gave it just enough strokes on a stone to break the corners, cleaned and oiled it and installed.

After shooting the carbine I tried this out. And it really works. Recoil on this pistol is now straight up- no twist- and a smaller jump. It also throws the brass straight up and back instead of to the side, which I was not expecting. Although it makes sense when you think about it. I only put about thirty rounds through(only so much time), but the difference was kind of amazing.

Definately glad I tried it.