After a range session, during cleaning I noticed that the bolt face of my Inox KM77RP in .243 Win presented two little dents, actually under a closer look with a magnifier, two spot, two little craters where some metal was lost. The craters are loctaed in the circle where the primers rest, concentric eith the firing pin hole.

A close friend reported me the same thing that happened to his Ruger in .338Win some years ago.

My question is, what caused this and more important, is this a real issue in terms of safety, durability and accuracy? Is it safe to leave this alone and don't woory at all?

tks in advance for any clues!

Hello Gustavo!

It sounds like you have experienced flame (gas) cutting erosion from leaking primer(s).

Were you shooting factory loads or reloaded ammo? Look at the primers of the fired roads. You might find signs of leaks around the primers. It could have been only one instance of a faulty primer or piece of brass.

If reloads, how many times have they been reloaded? How hot are the loads? When you seat new primers they should seat with some resistance if the brass is in good shape. It is a "feel" thing that you can tell with new brass. The pockets will loosen as the number of times they are reloaded goes up. Hot loads will loosen them faster.

You will often see this erosion on milsurp bolt faces. You can also see it on ANY brand of bolt; being a Ruger in both instances you mentioned has nothing to do with it.

Bob

quote:

Originally posted by Gustavo:
actually under a closer look with a magnifier, two spot, two little craters where some metal was lost. The craters are loctaed in the circle where the primers rest, concentric eith the firing pin hole.

I have some Federal Match primers (205) that split the radius of the primer cup every so often regardless of gun used and with normal operating pressures.

Having 2000 left, I only use them in very reduced cast bullet loads with which I haven't had one split again.

I would eliminate the ammo if factory or the primers used if reloads.......

BigRx

quote:

Originally posted by B Stephenson:
Hello Gustavo!

It sounds like you have experienced flame (gas) cutting erosion from leaking primer(s).

Agree. Gustavo, if you are using handloaded ammo, switch primer brands. if the problem still persists, you will have to reduce the powder charge.

Is it possible for you to post a photo of the back of the cartridges you fired before you noticed this problem? But then again, this problem may have been going on in the past as well.

Just be careful with your reloads.

If you are using factory ammo, and can see signs of soot around the spent primers, find another brand.

I've been seeing a pitted ring for so long on so many rifle bolts, I thought it was normal.
Or actually I didn't think at all to be exact.

Now I'm just wondering if the primers can leak
a little before the pressure seals them, a bit
like getting soot on the case necks??
John L.

Hi All,

Tks for the great answers!

Yes, after examining more carefully the spent cases, I found one with two small leakages, that ripped off some brass, so the culprit was there as you have said so well.

Question remains the same, if this a real problem (beyond appearance), should I replace the bolt?

tks again for your answers!

quote:

Originally posted by Gustavo:
Question remains the same, if this a real problem (beyond appearance), should I replace the bolt?

Saludos, Gustavo

The bolt is fine. If appearance is an issue, a gunsmith can weld up the pits and dress it all down to match.

A bigger concern is the firing pin's tip. Gas leakeage through the primer will erode the tip and create little sharp edges that will pierce good primers.

It would be wise to buy a new firing pin.

Que sigas bien.....