For my own education could someone explain to me what a gas cut in your boltface looks like and how high do pressures need to be to get these, are they common ??

Does anyone have a pic of one they could post.

Thankyou.

[ 10-02-2002, 16:33: Message edited by: PC ]

I read that too and went I own a custom 98 and a couple of FN's so I was curious about that as well.

They can look like small pits in the bolt face to gouged/melted lines and everything in between. Basically, any removal of metal from the bolt face or firing pin hole. If the hole for the firing pin looks out of round, check your firing pin for damage.
It can occur with high pressure loads or low pressure loads with pierced primers or loose primer pockets.
A friend of mine has a 17 Mach IV that had problems with one batch of loads. He had a few pierced primers and later discovered that he used pistol primers in them. Apparently the pistol primers are softer/thinner than rifle primers. His bolt needed to be replaced.

Yea - I've got a 25-284 with some small pitting around the firing pin hole due to some failed primers from way back when - bad batch of CCI's - but I got the impression these gas cuts were seen on basically new or limited fired 98 actions that BRNO uses - would suggest that military rounds had failed or had leaky primers/pockets - I guess this is what he means.

PC---

Many European military primers were very hard.....too hard to expand and seal against the primer pocket, especially when the going got tough and rifles were shot with wet, dirty, or obstructed barrels.

It cuts a ring around the firing pin hole and can wreck the bolt if it continues long enough.

It can be repaired, but it's fairly expensive to cut the old portion away, TIG weld, re-face and re-heattreat.

No primer seal 100%. There is always a bit of a leak. The higher the pressure, the more the leak. The gas ring on the bolt face is a good way to tell how hard a certain rifle was used if you are looking at a used rifle. Check at a gun shope with used rifles. All of them will have that mark. It's a part of shooting.

Some of my bolt faces have that mark.

I found that a lot of 9 1/2's is splitting on the outside corner. I still have not returned them due to the hassle.

Don:

I had those same 9 1/2's many years ago.
Don't shoot them....
they really tore up my bolt face.

Remington ended replacing the primers, AND replacing the bolt in my Remington 700.

Here is an example of gas cutting the bolt face. As you can see, a nice outline of many fired primers has been cut into the face of the bolt...



Sam B.
http://www.fireflyarms.com

Thank you gents,

I have an extremely small burr or indent on the edge of the firing pin hole on my CZ .416 Rigby Bolt. I do not think it is gas cutting but rather a tooling mark. Any way's it looks nothing like the photo Sam B posted, it looks more like a tiny chip and it's not filled with the black colouring.

It is probably nothing, but I am a perfectionist with that sort of stuff, is this worth even worrying about ???

Thanks Sam for the photo.