Questions on ejector marks

[Bigwheel]

Some what new to reloading. Ive worked up a .308 load using Lapua brass federal 210m primers 175smk's and 43.8 grains of varget at a coal of 2.810. Shooting a GAP built rifle with a surgeon action an 20" bartlien 5r barrel with 11.25 twist rate.... So with all that info here is the issue. The load shoots amazingly around staying well under half Moa out to 600 yds and have had some groups under .25 Moa at 100 but I am experiencing some ejector marks on my brass. No other pressure signs but very light marks. This doesn't occur on all rounds but maybe 20 of the 100 or so I've shot. Is this brass still safe to use? Could it be that it's virgin brass and not fire formed? Or should I just reduce my charge and be happy with what I can get? Any help or pointers would be helpful. I am very precise when loading for this rifle and weigh each charge and projectile and measure every single round for consistent coal. Thanks for any help.

 

[BCP]

If the growth is minimal and the primer pockets are still fine then I would think it's okay. If the cases have grown considerably and the primer pockets are loose then it might be a bit much.

 

[Bigwheel]

BCP- how should I measure the growth and what would be considered excessive? Thanks for the help I'm just kinda learning as I go and unfortunately don't know anyone who reloads so its kinda hard to get help when needed. Just trying not to blow anything up!

 

[K_4c]

BCP- how should I measure the growth and what would be considered excessive? Thanks for the help I'm just kinda learning as I go and unfortunately don't know anyone who reloads so its kinda hard to get help when needed. Just trying not to blow anything up!

Find your applicable cartridge and compare specs. Also, a picture would help show the severity of your issue.

Cartridge Diagrams

best of luck bud.

 

[BuzzBoss915]

Do you know the difference between extractor marks and ejector marks? Extractor marks typically a gouge on the case head and ejector marks usually dents on the necks as thrown from a gas gun. Do you have a hard bolt lift?

I have a Howa that continues to gouge the rims even though I have taken it apart and filed the extractor a couple times. It never did it with the 22-250 barrel, but now that it's a 243Ackley, it does it consistently with fireforming loads. BB

 

[Bigwheel]

K_4c thanks for the diagrams those are helpful and I will try to post a picture as soon as figure out how. And Bussboss the marks I am getting are marks on the actual head of the case where the head stamp is. They are small very faint circles that you cant really feel as a raised bump unless running your nail across the case head. its as if the load is over pressure and causing the brass to flow back and into the ejector housing but I have no sticky bolt lift at this particular loading. when testing charges I got to a point that the bolt was hard to lift backed up from there.

 

[milo 2.0]

K_4c thanks for the diagrams those are helpful and I will try to post a picture as soon as figure out how. And Bussboss the marks I am getting are marks on the actual head of the case where the head stamp is. They are small very faint circles that you cant really feel as a raised bump unless running your nail across the case head. its as if the load is over pressure and causing the brass to flow back and into the ejector housing but I have no sticky bolt lift at this particular loading. when testing charges I got to a point that the bolt was hard to lift backed up from there.

The little circle is what most people call ejector marks. The case gets slammed into the bolt face, the circle is from the ejector hole on the bolt face. It is a clear sign of pressure, usually the second sign, the first being a cratered or puffed primer, the last being a stiff bolt.

You need either a primer change, or back off on the powder charge, if it persists with reduced powder, you may have to switch powders.

 

[BCP]

BCP- how should I measure the growth and what would be considered excessive? Thanks for the help I'm just kinda learning as I go and unfortunately don't know anyone who reloads so its kinda hard to get help when needed. Just trying not to blow anything up!

Well if you want to drive to Montello a certain half-crazed hermit relative of mine could help you out.

Failing that the easiest way is to check and see if they still fit in a shellholder after firing. If they do then resize one (I assume you are full length resizing?) and then see how easy they are to re-prime and how much trimming is required to get the length back to 2.005" or so. If they haven't grown a lot and the primers still take a bit of effort to seat then it's fine.

Reading primers is a mixed bag. Primers can be flat and cupped/cratered at safe pressures too depending on the bolt face and primer itself. Until the primer begins to 'leak' (you will see a dark sooty ring around the primer) you can't really tell just by looking at them.

My hunch is that you'll measure your cases and find little to no growth. If it is bugging you then try switching to a tougher primer and dropping your charge a little bit (say 43.5) but I really think you are fine.

 

[former naval person]

Two factors not mentioned are the bolt face itself...if the ejector hole is a bit rough or too sharp edged normal pressures can mark the case. Also, a bit too much head space can slam the case back into the face enough to cause a mark even at normal pressure.

 

[turbo54]

In my not so humble opinion:

If the length of your cases from casehead to datum is between .003" and .000" under the chamber dimension, your brass and chamber are clean and dry, and you're getting ejector marks, the simple answer is the chamber pressure is too high.

If your cases are .004" (or more) UNDER chamber dimension, it is possible to get ejector marks and not be overpressure.

Cases or chambers that are wet or have some residual lubrication will also give ejector marks even though pressure is ok.

It takes some serious pressure (when case/chamber is clean and dry) to get ejector marks on Lapua brass.

 

[BuzzBoss915]

Boy, I sure misunderstood the problem! If this action is similar to a Model 700, you could have, might have been helpful to describe the impression on the case head as a small circle. No doubt about it, in my opinion, you have excessive high pressure, you missed something in your load workup. Was there no cratering, or were the primers flat, at all? You will usually see one of those conditions before an ejector mark on the case head. I normally consider an ejector mark on the case head to be worth at least a one and a half grain reduction in your charge. It remains to be seen if your primer pockets are still tight, but the cases that have the ejector marks are suspect and will probably fail sooner than normal. BB