Ejector circles (pressure) from high primers?

[Juggerxxx]

I am getting ejector circles on most of the 150 pieces of 6GT Hornady Gap brass I have fired with a very mild load on a brand new barrel. Load = 108Eld, 34.5gr h4259 @ 2700fps and 35.5gr H4350 @ 2800fps.
When looking for what the issue could be I found that most or almost all the brass when primed will result in the primers sitting just slightly higher than the head.
could this cause the ejector circles I am seeing since the brass would not be sitting flat on the bolt face and when fired it would slam back into the bolt face?
I think the primer pockets are not deep enough because I have the setting turned all the way up on my priming tool. I do have a pocket uniformer but holy shit the pockets are tight and the uniformer just gets stuck in the pocket before it cuts enough. Maybe due to a radius at the bottom of the pocket.
I just wanted other opinions on high primers being a possible culprit for the ejector marks.

 

[PinesAndProjectiles]

Who headspaced the barrel? Are you FL sizing? How far are you bumping shoulders back?

 

[Juggerxxx]

This is all brand new virgin brass and I have not fired any sized brass yet. I am full length sizing and I am only bumping the shoulder 0.001” back.

 

[PinesAndProjectiles]

I'm wondering if your headspace is off is what I'm getting at.

I had a 6.5x47 that would leave ejector marks on the brass until I found that I was bumping the shoulders too far.

 

[TheOfficeT-Rex]

I'd lean towards headspace. Did you measure unfired brass? Does the fired brass chamber with little effort?

Did you measure how proud the primer was? Not that I think it matters, but I'm curious.

 

[918v]

Some rifles leave ejector marks just because. Sometimes you get ejector marks because you’re too close to the lands and the start pressure is too high.

 

[Juggerxxx]

I haven’t tried chambering already fired brass and will need to fire some since I have everything already sized.
The odd thing is that the shoulder on virgin brass only measures 0.001-0.002” less than fired brass. Meaning it did not grow as much as I am normally accustom to with other cartridges. Other cartridges seem to grow closer to 0.004”-0.005”.
Primes seemed to measure 0.001” too high. It was noticeable when seating bullets and measuring the ogive to base.

 

[oldfatguy]

You said it yourself. The primers are ABOVE the case head. I uniform all my new cases and some are a real chore and take several cycles to clean up. Use a chip brush to remove the cuttings from the uniformer between cycles. High primers may or may not cause the ejector marks but are a real bad thing in any case.

OFG

 

[czim]

The edges of the fired primers are still very radiused. This to me says you are not over pressure.

 

[Juggerxxx]

The edges of the fired primers are still very radiused. This to me says you are not over pressure.

That was what I had also looked at as a counter indicator and was looking for the additional assurance. Still odd to see the ejector marks and those have almost always been my indicator for the onset of pressure in every other cartridge I have loaded for. The 6GT seems a bit of an odd ball.

 

[XLR308]

I don't know what action you are using but in one of your pictures other than the ejector imprint you also have primer flow around the firing pin indent.
How many of your primers are showing that ?

 

[Juggerxxx]

I don't know what action you are using but in one of your pictures other than the ejector imprint you also have primer flow around the firing pin indent.
How many of your primers are showing that ?

I do Remember looking for that and didn't recall seeing much of it. Here is the only other photo I have showing more than a couple of cases if you can see more? It’s the same photo just zoomed out

 

[XLR308]

Six out of the eight cases I can see some primer flow, the other two may have just can't tell from the angle.
That's why I was curious about what action you were using.
I don't own a 6GT but in 6.5x47 in my Kelbly Atlas action I use primer flow as my indicator of pressure and don't exceed charge weights that show it.
Some actions show it at relatively low charges and is a false indicator.

 

[oldfatguy]

Six out of the eight cases I can see some primer flow, the other two may have just can't tell from the angle.
That's why I was curious about what action you were using.
I don't own a 6GT but in 6.5x47 in my Kelbly Atlas action I use primer flow as my indicator of pressure and don't exceed charge weights that show it.
Some actions show it at relatively low charges and is a false indicator.

Rem 700 actions are notorious for primer flow at any pressure.

OFG

 

[918v]

I do Remember looking for that and didn't recall seeing much of it. Here is the only other photo I have showing more than a couple of cases if you can see more? It’s the same photo just zoomed out View attachment 7435152

What action are you using?

 

[XLR308]

Rem 700 actions are notorious for primer flow at any pressure.

OFG

Very true that's why I was asking.
I wasn't so much interested in action as i was small or large firing pin.
The larger diameter firing pins may show some flow regardless with small primer high pressure cartridges.
If I'm wrong please correct me.
It looks like a small firing pin indent from the pics but a little hard to tell for my old eyes.

By the close up pics it almost looks indented instead of flowing into the ejector plunger hole, you might check and make sure the plunger will atleast depress to flush with the bolt face.

 

[Rocketmandb]

For the ejector marks, high ejector spring tension?

 

[bax]

I am getting ejector circles on most of the 150 pieces of 6GT Hornady Gap brass I have fired with a very mild load on a brand new barrel. Load = 108Eld, 34.5gr h4259 @ 2700fps and 35.5gr H4350 @ 2800fps.
When looking for what the issue could be I found that most or almost all the brass when primed will result in the primers sitting just slightly higher than the head.
could this cause the ejector circles I am seeing since the brass would not be sitting flat on the bolt face and when fired it would slam back into the bolt face?
I think the primer pockets are not deep enough because I have the setting turned all the way up on my priming tool. I do have a pocket uniformer but holy shit the pockets are tight and the uniformer just gets stuck in the pocket before it cuts enough. Maybe due to a radius at the bottom of the pocket.
I just wanted other opinions on high primers being a possible culprit for the ejector marks.

Your primers are not flattened. That suggests that you have low to moderate pressure. But you do have ejector marks. That suggests that you have high pressure. One of those signs is wrong. I don't know that caliber so I will rely on your statement that this is a mild load. In that case the ejector mark is a fake sign. So test it.

But before you do, check the edges of the ejector hole in the boltface. If it has burrs, either push the ejector deep into the hole and scratch off the burrs or remove the ejector, scratch off the burrs, and reinstall the ejector.

Here is a way to test ... Seating into the lands increases initial pressure. Don't set

Take 5 pieces of brass, seat the bullets so that closing the bolt seats the bullet slightly into the lands. Thus, when the firing pin hits the primer, the brass won't move.

Take 5 more pieces of brass, uniform the primer pockets, seat bullets slightly into the lands. since the primer pockets are cut, primers should seat deeper. When fired with bullets seated into the lands, the brass won't move.

Compare A and B to what you already did. One should be different from your baseline. If not then check your assumptions about pressure.

Some comments:

If the brass is new, it probably doesn't need any shoulder bump. The neck may need to be sized (maybe round, maybe smaller) but the body is probably right just as it is. I have never bought a new case that was too long.

Suppose you set the shoulder back too far so the case is too short. The firing pin will push the round forward until the shoulder hits the front of the chamber, then continue moving forward and cause the primer to fire. The expanding gases will cause the thinnest part of the case (the part around the shoulder) to expand and "grip" the chamber walls. Pressure then pushes the heavier part of the case backwards until it fetches up against the bolt face. Speculating - the combination of movement and pressure might cause the brass to flow into the ejection pin hole. Continuing to speculate, it could be that this wouldn't happen if the base of the case was already tight against the bolt face hence my suggestion above to create extra long rounds in order to make that happen. Repeating myself, be careful with bullets seated into the lands.

 

[Juggerxxx]

All good material and I may have to go down those roads if the ejector circles continue after finally trying some once fired brass.
I did forget to mention that I had zero indication of sticky Or heavy bolt lift.

 

[supercorndogs]

How about a picture of the ejector hole. Considering there is no smearing in the circles, I would suspect a bur or a high spot around the hole for the ejector. Who you get them from pressure. The pressure is forcing the brass back into the ejector hole. Then you get stiff bolt lift as you rub off the offending brass that is attempting to hold the bolt shut, via the ejector hole. The marks in O.P show no smearing which would lead me to look around and see if something is marking the brass.

 

[Juggerxxx]

I tried to take the best photos possible. When I run a knife across the face of the bolt and into the hole, I do not feel any raised surface or burr.

 

[supercorndogs]

It looks like a high spot around the edge of of the hole to me, like what you would expect if a drill was pushed through from the back side. Are the marks accompanied by heavy bolt lift?

 

[Bandit320]

It looks like a high spot around the edge of of the hole to me, like what you would expect if a drill was pushed through from the back side. Are the marks accompanied by heavy bolt lift?

I have a Howa 1500 that did the same thing with light loads and no other pressure signs. Feeling the case head with a very sharp knife it’s definitely indented in the case like you’re talking about.

 

[918v]

Looking at the bottom of the fp indent, I see signs of metal wanting to pop back out. You’re going to get pierced primers. Could be not enough neck clearance or too close to the lands.

 

[Juggerxxx]

It looks like a high spot around the edge of of the hole to me, like what you would expect if a drill was pushed through from the back side. Are the marks accompanied by heavy bolt lift?

Zero heavy bolt lift at all and that is what is strange.

 

[Juggerxxx]

Looking at the bottom of the fp indent, I see signs of metal wanting to pop back out. You’re going to get pierced primers. Could be not enough neck clearance or too close to the lands.

50 of the 150 rounds fired so far were during a seating test. ~98% of those 50 showed the ejector circles and some rounds were seated 0.093” off the lands.
You mention neck clearance and I’m going to turn some necks to see if that helps. I did notice on fired brass that there is very very very little carbon on the outside of the necks. And what little carbon is there only makes it 3/4 down the neck. Not something I am accustom to seeing especially on virgin brass. A bullet will also not drop into a fired case UNLESS I chamfer the inner diameter of the mouth. Even then it is a tight fit but the bullet will drop freely. If a tight neck is the issue, wouldn’t I expect to have heavy bolt lift?

 

[918v]

Not necessarily.

Besides your neck diameter, is the body of the chamber cut tight as well?