Is this cratering?

[MudRunner2005]

Yes, but in my opinion not from excessive pressure, but from an loose fitting firing pin. The primers are still well rounded on the sides with just a bit of a flattening of the face. Is the load under book max?

Jeff

Exactly! If it was excess pressure, then it would be filling up the rounded edges of the primer pockets to make a flat surface where the primer was pushed up against the bolt face. When you deprimed the cases, the primers would almost have a lip on them on the side that was exposed to the bolt face.

 

[MagnumManiac]

Have a look at your bolt face with a magnifying glass, I bet the firing pin hole has a bevel in it, as done from the factory. Every recently manufactured Remington, and a few Winchester rifles I've seen have had this, why, I do not know. I had this on 2 actions I bought recently, asked Remington what the story was, no reply or explanation, so I bought PT&G one piece bolts.
Your brass looks fine to me. Your first indicator with excessive pressure is nearly always ejector marks, whether primers are flat or not.

Cheers.
gun)

 

[deadidarren]

the first question i would ask is the rifle a rem 700 if so this is very common

and not a problem if you keep your pressures at a normal level .

have a look at the pic the one on the left is what i use in my .223 as

a working load for culling and the one on the right is excessive pressure

as can be seen by the excessive flattening of the edges of the primer and

the ejector mark in the case head as marked with the red arrow .

hope this helps .... and yes the rifle is a rem 700.

 

[LoneTraveler]

Mr. Iclimb, Check the ridge around the edge of the firing pin indent. check close, There may be rough sharp place where the firing pin hole indentation is giving back toward the bolt. I would check the Firing Pin Spring. If the spring is weak it will allow the pressure to start shoving the firing pin indent in the primer back toward the bolt. I inherited a 722 Rem. that would make primers look similar, sometimes a sharp edge around firing pin indent and had some that would shove back into the bolt so far smoke came out of the bolt. Accuracy had dropped to about 2 inches. A new Firing Pin Spring and that cured the problems and accuracy to 3/4 inch returned. Good Luck in finding the true problem.

 

[upacreek]

This peaked my curiosity, how would a firing pin improve accuracy? Slow travel? Maybe I have something to learn.

 

[Iclimb]

yes its a 700 rem. Sendero. It has been trued etc. I finally worked up using bergers seated .005 off the lans. I worked up to 75gr. of retumbo and started seeing ejector marks and flatter primers like you guys discussed. Thanks for the help.

 

[MR.SWIFT]

this has my curiosity as well. my 300 ultra mag that was re-barreled to 300 tejas shows primer cratering similar to pic show. I had not shot the 300 prior to the re-barrel so have spent some time trying to determine why. with the ammo sent with the barrel this cratering is very distinct. reloaded same bullet with reloader33 same primer and it is much improved but still present. just to a lesser degree. loading 98grs of reloader33 under a berger 210vld fed215mag primers. oql is 3.875 I believe

 

[dkhunt14]

Call Gre tan rifles. He bushes bolts to stop the cratering. Matt

 

[davkrat]

One of my newer Remington 700's does the exact same thing from starter loads all the way up. I've worked up to ejector marks before really seeing much flattening of the primers. I'm not concerned about the cratering I see it at all pressure levels and I've heard similar from numerous others with newer Rem 700's.

 

[dkhunt14]

The thing about cratered primers is you are close to piercing or blanking them. If you piece a primer you can get stuff in your eyes, then you need your bolt torn apart to get out the debris. If you shooting at distance the shot goes low. That could mean a crippled animal. The trigger a lot of times breaks when this happens. At best it needs torn apart to get the debris out of it. I have seen many of Jewel have to go back because they broke from a punctured primer. Matt

 

[dkhunt14]

This peaked my curiosity, how would a firing pin improve accuracy? Slow travel? Maybe I have something to learn.

Firecontrol is important in accuracy. I have seen guns shoot major vertical at 1000 yards and put in a new spring and it goes away. Matt