brass shavings on bolt face

[jps120]

I was cleaning my rifle today and noticed brass shavings on the bolt face. I believe it is a head space issue but want to see what yall think, and to see if I have done any damage to my rifle. I switched bullets from 105 bergers to 105 amax and reduced the powder (Varget) down to 28.5 gr and started from there and worked up to 29.5 gr. Some were jammed .01" and some were off .01" the lands. ALL showed signs of pressure (see attached picture). looks like extractor marks and primer was cratering. I just checked headspace on some loaded rounds and it is 1.164" to 1.165". I checked the fired brass and it was showing 1.166" to 1.165". I was sizing my brass based off 1.167" headspace (1.166" fired round plus the brass springing back .001") so a loaded round would be 1.165". based off this I think I should bump the shoulder back, but how far? also do you think I have done any damage? And I never noticed any rounds that were hard to chamber or any extreme pressure to left the bolt.

 

[jps120]

rest of pics

 

[jonbearman]

I don't think you damaged anything but how much spring pressure do you have on the ejector spring because if it is a strong spring it could be the cartridge is rubbing on the extractor that could have a burr on it hence the shaving. Can you post a pic or 2 of the case heads you shot and ejected. That cartridge has a heavy imprint from the ejector. Punch the pin out and remove the ejector and see if there is crud and shavings in the hole and secondly the firing pin hole needs bushing. Have gre-tan in Colorado do it. He has fair prices and rapid turn around.

 

[Ledd Slinger]

Too much pressure for sure. Brass shavings = hot load. Ejector marks AND brass shavings = TOO hot of a load.
Doubt it's a heaspace issue since the loaded and fired rounds are very close. Not all reloading data creates the same pressures in every rifle. Things can and will vary. Try backing the load off half a grain or seating the bullets a little deeper.

No damage done. I have a couple rifles that leave brass shavings on the face all the time because I hot rod the speeds for hunting. Running them on the ragged edge and they always shoot well.

I just re-barreled a 6.5 Rem mag. The last barrel could only handle 51gr of RL-17 with a 140gr bullet at 3150 fps before loosening primer pockets and showing ejector marks. New barrel in the same exact caliber easily handles 52gr of RL-17 with a 140gr bullet at 3209 fps and there are no pressure signs at all. Same caliber, different barrels, BIG difference.

 

[NorCalMikie]

Headspace issue? (case too short for the chamber with different bullets added, round fired and blown back against bolt face causing ejector marks) Once the brass is fireformed to chamber, no more issues. Damage to rifle?? Not even close. 8)

 

[jps120]

The rounds I loaded at 28.5 did not show heavy ejector marks like the one in the picture. if there was one if was very very faint. However, all rounds had a cratered primer. Isnt that a sign of to much pressure?

 

[NorCalMikie]

Case moves when fired because it's too short. Once case is formed to chamber, it can't move anymore. And, if case is "too short", primer can back out, get hit be firing pin and be pushed back into pocket causing cratering and piercing.
Start with formed brass before you go any further. And, make sure you don't push the shoulder back too far when resizing or you'll end up with the same thing again. You can also load long, ( into thelands) single feed and see how the brass formes.
If the fired case will chamber just after it's fired, neck size, reload and go shooting.

 

[jps120]

Sorry mike I never said but this brass has been fired and sized about 7 times. And half the bullets were seated long .01 into the lands

 

[fguffey]

Isnt that a sign of to much pressure?

If it happened to me I would say the firing pin should be larger in diameter of the hole in the face of the bolt should be smaller. Primer flow around the firing pin is not normal. If the primer is pierced I check the firing pin spring for pressure, pressure inside of the primer can push the firing pin back, when that happens a hole appears in the primer. the primer should conform to the protruding firing pin.

F. Guffey

Then there is the other matter, when the bolt rotates the case can rotates, If the bolt is rotated and the case is stuck in the chamber there could be shaving.

 

[Ledd Slinger]

The rounds I loaded at 28.5 did not show heavy ejector marks like the one in the picture. if there was one if was very very faint. However, all rounds had a cratered primer. Isnt that a sign of to much pressure?

Then back it off til you dont see any ejector marks. You can get cratered primers with acceptable pressures from things like too thick of a firing pin, too thin of a primer cup like from non-magnum primers, etc... Usually flattened primers with the addition of a crater are a better indication of excessive pressure, but not always the case. Ejector marks are the definite sign of excessive pressure.

Have you chronographed the loads? Sometimes the speed of your bullet can help yo determine if you are at max pressure when you see minimal speed gains after adding incremental powder charge weight of the same amount.Say you are pushing it at 2900 fps, then gain 50 fps for every .5gr added, then suddenly you see only a 20 fps gain with the last .5gr increase. That last .5gr increase with much less gain in speed often means you have exceeded max pressure and are risking a case rupture.

 

[jps120]

I have not chronographed it yet I just picked one up today and I was going to re do the test starting at 28 grs and work up in .3 gr increments

 

[M-61]

Normally I am not concerned with primer cratering and don't consider it a sign of a 'too' hot load, rather a firing pin that maybe should be bushed. Maybe it's the pic (or my eyes) but the cratering really seems to be off to one side.
Usually I see a nice even raised area around the entire indentation. What would concern me is the ejector mark which is really pronounced. Getting HOT!
Also are the cartridges and chamber free of oil etc. when you shoot?

 

[Ledd Slinger]

I have not chronographed it yet I just picked one up today and I was going to re do the test starting at 28 grs and work up in .3 gr increments

Good idea. I would actually start at 27gr to get a good reference of incremental speed gains. Pay close attention to the speed gain patterns. You will probably start seeing less speed gains with each .3gr increase as you start to see the ejector marks.

 

[jonbearman]

Looking at the picture of the primer it has a splash on one side only and the picture shows an off center strike on the primer. It looks like a Remington bolt and I wouldn't hesitate having gre-tan fix the bolt period. I had a Remington that had horrible off center strikes all caused by previous primers leaking. As soon as I got it back and fired it , the original rounds that were piercing didn't and pressure looked fine. Remingtons are notorious for this in the first place. Especially if they may have had a few primers leaking and distorting the hole in the bolt head. If you are running a 6 br with 105 grain bullets the 28.5 should be a safe load. Have you tried off the lands to see if it shoots ok or better? Like other posters have recommended start lower and work up. Get it bushed and they will turn your firing pin down and it will fit perfect without the radius on your bolt head. That is not a classic way to machine a bolt head as the factory is sloppy as far as I an concerned. IMHO

 

[jps120]

Should be oil free I place a drop of oil on a patch and wipe the bolt down but not the face and I place a dab of grease on the back of the lugs. After I finish cleaning the barrel I place a light coat of oil on a patch and run it through the barrel. Then run a dry patch through after that.

 

[CatShooter]

Your firing pin does NOT need to be bushed - you have genuine cratering - that, plus the ejector marks, put you in serious high pressure.

Bring it down.

 

[/VH]

jps120,

I agree, you're running too hot; I base my opinion on the ejector recess mark on the case in your photo.
I expect the brass shavings on your bolt face are likely from the brass that protrudes into the ejector recess and then is sheared off upon rotating the bolt. Although, I have seen brass shavings accumulate on a bolt face just due to the extractor riding over the rims of the cases and either the extractor being rough or the case rims having a bit of a burr on them. This can be tested for by cycling several empties, or if done in a safe manner, several loaded rounds through the action, without firing, starting with a clean bolt face and then checking for shavings.

 

[savagedasher]

Looks like the bolt face s not true to the chamber. Check the bolt . I think you will find all the pressure on one lug. Larry

 

[/VH]

I have not chronographed it yet I just picked one up today and I was going to re do the test starting at 28 grs and work up in .3 gr increments

Good idea. I would actually start at 27gr to get a good reference of incremental speed gains. Pay close attention to the speed gain patterns. You will probably start seeing less speed gains with each .3gr increase as you start to see the ejector marks.

Ledd Slinger,

Is it not also likely that when exceeding safe pressure limits that wild velocity excursions may occur?

 

[Ledd Slinger]

I have not chronographed it yet I just picked one up today and I was going to re do the test starting at 28 grs and work up in .3 gr increments

Good idea. I would actually start at 27gr to get a good reference of incremental speed gains. Pay close attention to the speed gain patterns. You will probably start seeing less speed gains with each .3gr increase as you start to see the ejector marks.

Ledd Slinger,

Is it not also likely that when exceeding safe pressure limits that wild velocity excursions may occur?

It definitely can, nothing is guaranteed. But I generally find that problem with powders my rifles do not like by producing large ED, SD and poor accuracy. Though that's just my experience.

I assume the powder he is using gives good accuracy or he wouldn't be using it. Though he hasn't stated the accuracy level yet so I may be wrong there.

I try to use a powder that a rifle will shoot good with using various charge weights (ladder test). Generally when that happens, the speed gains seem to be pretty consistent and often have low ES and SD. The gains won't be "exactly" the same, but they are usually pretty close. Just depends on the amount of charge added as to how far apart the gain variances can be.

The reason I told him to start at a lower charge to get a better reference is because they won't be exactly the same. This way he can get a rough average of the gains. Then when you see less than half or no gain at all compared to the other gains, it let's you know to not dare go any further.

But in hlthe OP's case, if speed gains remained consistent as ejector marks started re-appearing, I would stop at that point as well and back it off a little bit. Definitely don't want to go any further when seeing ejector marks regardless of what the chronograph tells you