SIG 226 Firing Pin Data

[Dave P]

Hard to believe, but I am getting FTFire problems with my 357SIG pistol. Light primer strikes, it looks like.

It may be my old / oily primers I found. It may be crud in the Firing pin holes (I did remove a single hunk of primer splash).

So it is nice and clean in and out now. But it seems to me the firing should extend more: it sticks out about 60-70 mils. When I remove the crosspin that retains the FP, the pin extends almost twice as much (100 mils).

Question: how far should the firing pin extend upon firing?

TNX
Dave

 

[rcmodel]

.070" sounds about right. I don't have one to measure but that should be in the ball park.

Anyway, it could be bad primers as you mentioned, or it could be ammo with short cases, giving excess headspace.

Try chamber-checking some of the misfires in the barrel with it removed from the slide and see if they stop just flush with the end of the barrel hood.

rc

 

[Dave P]

Could be headspace, rc. I did not save any misfires, of course. (dissected the previous ones - didn't learn a whole lot)

I did just re-adjust the dies to about max on the wilson h/s gauge; and those align with the barrel extension hood do-dad on the top.

Some of my loads are too hot, and I get primer flashings back into the fp hole. Shame on me.

I also have a boatload of small rifle primers, which should be less likely to crater and splatter, if I happen to load too hot. But I have not tried those before, so I will back off my nominal book load of 10 gr 800x with a 124 JHP bullet.

Also, some cases have soot on the head and rim. I would expect this if the primer developed a pin hole - but I don't see any holes??

Dave

 

[rcmodel]

First, DO NOT use Sm Rifle primers.

If you run into pressure that a normal small pistol primer will not safely handle, you are about 10,000 PSI over & above what a .357 SIG case can safely handle.

It is also unlikely that many pistols will have enough firing pin energy to set them off reliably.

According to my Lyman loading manual, your 10 gr 800x with a 124 JHP bullet is a 1/2 grain over a maximum load. They show 9.5 grains giving 39,300 PSI, which is only 700 PSI below the design limit of the .357 SIG case.

Hodgdon shows 10 grains MAX at 36,100 PSI with a plated jacket Speer Gold-Dot, but does not apparently recommend 800X with conventional Jacketed bullets that light.

Also, some cases have soot on the head and rim.

Sounds to me like blown primer pockets. Your hot load is causing case head expansion to loosen the primer pockets in the cases and they are leaking!

I think you need to back off at least a half grain for starters, and perhaps buy a box of new Sm Pistol primers.
If they work without mis-fires, the old primers you have are bad, and should be discarded.

rc