357 Primer Problems/ Frame ?

[wanderer]

I have a SB1 frame (made in 2006, according to the SN) with a 357 barrel. Problem is, when I shoot 357's, the primers flow into the firing pin hole so bad that it makes the gun hard to open. I either need to give the barrel a good pull, or hit it with the heel of my hand to open it. Shooting 38's works fine, and the primers look completely normal. I loaded up some light 357's (supposedly about 28ksi pressure) with small rifle primers, and it was hard to open, although not as bad as with factory ammo. The firing pin measures .095" and the FP hole measures .099". .004" seems like a tight enough clearance, so I doubt that the clearance is the problem. I checked headspace and it is good.

I think I know what is going on, but I'm not sure. I think that the primer flows and pushes the firing pin back into the FP hole. I tested this by taking barrel off the frame, cocking the hammer, and pulling the trigger. I held the trigger back, which of course made the firing pin stay forward. I then pushed on the firing pin with my free hand. I was able to push the pin back into the hole with little trouble. The shape of the "volcano" on the primer fits this scenario also.

Has anyone had similar experiences? If so, how did you fix it? Is a .095 diameter FP normal? I know that some of you with 357 maxes on SB1 frames use rifle primers to eliminate this problem, but that didn't fix my problem (although it did reduce the severity). I really don't know what to do except just shoot 38's. I could bush the FP hole, but that seems like it would be a major pain because of how these frames are made.  I would rather buy an SB2 frame than mess with bushing the FP. Shooting 38's doesn't bother me too much because the biggest animal I hunt with it are coyotes and I have a bunch more 38 brass than 357, but I would like to have the option of 357's if possible.

Suggestions?

Thanks in advance.

[mechanic]

If you reload, switch to rifle primers. 

[quickdtoo]

Yup, even different brand primers may make all the difference in the world. 

Tim

http://www.jamescalhoon.com/primers_and_pressure.php

[wanderer]

As I said in my original post, I have unsucessfully tried rifle primers, but I've only tried CCI's and Winchesters because that's all that's been available. If I find some Rems or others, I'll give them a try.

Thanks for the link quick!

[trotterlg]

In small rifle you need to try the Winchester 7 1/2's or the CCI 450's or BR4's to get the thick cups.  I would load up a primed case, fire the primer only and measure how much it sticks above the rim to see what the true headspace is on the barrel.  .004 is quite a lot of clearance for the firing pin.  Larry

[cwlongshot]

I would also check the firing pin protrusion at the breech face. I'll bet its a tad deep. It should be 40-50 thousandths.

CW

[dieselten]

as a field expedient to ease the opening of the action, you can cock and dry fire to push the primer back a little.

[wanderer]

Thanks for the replies folks. I just measured the FP protrusion and it's .042", so that appears to be fine. I think I only tried the standard SR primers, so I'll try to find some with the thicker cups and give that a try before I do anything else. Also, since it seems that my initial guess about the firing pin clearance being tight enough may have been wrong, I'll probably turn a new firing pin that is a few thousandths larger diameter to take up some of the slop and see if that helps.

Thanks again.

[aromakr]

With my .357 Max I tried loading the CCI 41 or Nato primer, that cup is so thick 3 out of 10 would not fire on the first try. Not a heavy enough hammer fall. Changed to Win 6 1/2 and the problem stopped, so in my opinion you can get too thick a cup also, so be careful.
Bob

[quickdtoo]

A Wolff hammer spring may solve FTF issues with heavier primer cups, weak OEM springs even on new firearms is a known issue. 

Tim