Can anyone advise which heli-coils should be used in a P229 40/357 so that the original factory stock screws will work?

I don't think that you will find helicoils in the size you need. Because many gun manufacturers seem to use screws with a non standard thread pitch. In addition there are also minimum thickness requirements for helicoils that I don't think will fit. For example the smallest size offered is a #1-56 which is pretty tiny. That particular helicoil requires a minimum thickness of 0.203 inches. BTW if you think you can "cheat" on the thickness by grinding the insert shorter after installation I'll tell you flat out that won't work, as soon as you try and put in a screw the insert will spin right out of the hole.

I think the screws are m4x.7 and there are helicoils that size. I have no idea if there is room in there for them. I think most people just tap them to a larger diameter and source screws to match, but I'm not an expert on this area. And me personally I'd consider one of the thread repair chemicals as a first try at fixing it.

FWIW, I'm having a gunsmith do this.

quote:

Originally posted by Scooter123:
I don't think that you will find helicoils in the size you need. Because many gun manufacturers seem to use screws with a non standard thread pitch. In addition there are also minimum thickness requirements for helicoils that I don't think will fit. For example the smallest size offered is a #1-56 which is pretty tiny. That particular helicoil requires a minimum thickness of 0.203 inches.

Thanks. Over the years I heard of others successfully repairing (if not "upgrading") their P-series frames with heli-coils, so I assumed they'd be the route to go. I just searched online, and I'm not seeing a better option. That said, I'm open to other solutions.

quote:

Originally posted by Scooter123:
BTW if you think you can "cheat" on the thickness by grinding the insert shorter after installation I'll tell you flat out that won't work, as soon as you try and put in a screw the insert will spin right out of the hole.

Interesting. I thought the spring mechanics would keep the insert in there. I wonder if pairing with a thread locker might help?

quote:

Originally posted by hrcjon:
I think the screws are m4x.7 and there are helicoils that size. I have no idea if there is room in there for them. I think most people just tap them to a larger diameter and source screws to match, but I'm not an expert on this area. And me personally I'd consider one of the thread repair chemicals as a first try at fixing it.

M4x0.7. Thanks.

I believe, for your smith to use the M4 screws in a heli coil, he will be drilling out and retapping with a heli coil tap for the insert. Those inserts come in their own external thread sizes and require a heli coil tap. I think this is what you will find.

The helicoils are too long.
Every time I do one, I drill and tap a hole in a piece of 2x4 near the edge.
I then thread the helicoil in so that it measures the same (less .010) as the frame where the grip screw goes in. Next, I use a small cut off wheel on a Dremel to cut it flush with the wood. Last step is a push with a wood chisel to pop out the new modified helicoil.
Maybe there is a better, easier way to shorten the coil, but this is the only way that worked for me.