Primer Blow Out with NO Over Pressure Signs?

[BuffCyclist]

The 1st pic on the right looks like its a loose primer to begin with. Could be a Swager was not set up correctly. Or primer pocket reamed out to much. LC brass has a thicker webbing to the case and should be able to get 4 - 6 reloads out of them. Looks like you've done your homework as far as data goes.

Nope, that is the blow out I was talking about. That round is the one that locked up my bolt (after research tonight, locked/sticky bolt is due to overpressure and a very hot load) in which th eprimer just fell out. All of the cases primed as normal, none seemed light.

It's LC LR brass, so there is no crimp, it wasn't swaged or reamed. I only deprimed, cleaned, full length sized, cleaned (de-lube), then loaded.

[DSB OUTDOORS]

Nope, that is the blow out I was talking about. That round is the one that locked up my bolt (after research tonight, locked/sticky bolt is due to overpressure and a very hot load) in which th eprimer just fell out. All of the cases primed as normal, none seemed light.

It's LC LR brass, so there is no crimp, it wasn't swaged or reamed. I only deprimed, cleaned, full length sized, cleaned (de-lube), then loaded.

That could be part of the problem. All L.C. Military brass has a crimped primer pocket. I have swaged many, many, 5.56 and 7.62 so the brass you have has already been processed. Just a thought. Center pic. crimp, right some what removed, left removed.

[Hoser]

That could be part of the problem. All L.C. Military brass has a crimped primer pocket.

LC Long Range ammo (LR-118) is not crimped.

[Hoser]

When brass flows into the ejector you are already pushing it. Primer cratering is not a very reliable indication of pressure.

[DSB OUTDOORS]

LC long Range ammo (118) is not crimped.

Ok fine then. Just trying to help.


So the problem still remains.................

[BuffCyclist]

Ok fine then. Just trying to help.


So the problem still remains.................

Yea, I kept trying to indicate it was LC LR but what can ya do

I mean, I guess I could have been maxed out but I expected to get to at least 2700 FPS with this 24" barrel when I hit max. After finding out I didn't crimp after all, it makes me go back to thinking it's either loose primer pockets, undersized primers (out of spec) or magnum primers, though with the magnums I would expect the velocities to be higher than what I got because they're in line with the powder loads and standard primer velocities.

[Zombie Steve]

Yea, I kept trying to indicate it was LC LR but what can ya do

I mean, I guess I could have been maxed out but I expected to get to at least 2700 FPS with this 24" barrel when I hit max. After finding out I didn't crimp after all, it makes me go back to thinking it's either loose primer pockets, undersized primers (out of spec) or magnum primers, though with the magnums I would expect the velocities to be higher than what I got because they're in line with the powder loads and standard primer velocities.

Your headstamp doesn't start looking like your bolt face because of crimp, undersized primers or loose pockets regardless of what speed you're getting. It's also unlikely they put mag primers in the box. The loads are overpressure plain and simple. My best guess is you're too close to the lands and some of the bullets' ogives are long / inconsistent and jamming the lands. As to speeds, some barrels are just slower than others. If it makes you feel better, my 168 target load averages 2,585 from a 24" Rem barrel and I'm not changing anything. You can try different combinations of components, but you can't tell the rifle what to like. It tells you.

[XC700116]

Thanks for the other possible places to look.

First, I was loading to 2.800. I don't know where the lands are, I tried the dowel method (dowel down bore to face of bolt, mark with knife, put loosely sized neck/bullet in chamber, slowly slide bolt forward but don't lock, put dowel down bore again and mark with knife) but when I did that I was getting almost exactly 2.8" and I did it a good dozen times. So either I wasn't doing it right, or the distance truly is 2.8 in which case I should have more than enough room before touching the lands.

I was checking the scale with my 20g check weight every time I changed charges and it never varied.

True, I do have IMR-4895 (only other rifle powder) but it is unopened and I just double checked, so the only powder I could have used was IMR-4064.



Yes and no. The box says they are for Standard rifle loads, but that doesn't mean Winchester didn't put magnum primers in a standard box.



I was weighing every charge, not using a powder dropper, so no extra grains made it through.

___

I decided I was going to go pull 10rds (38.0-39.6gr) tonight and reprocess/weigh/seat/etc them but then I thought I’d look for a crimp first. Turns out, I did NOT crimp them. I bought the crimp die, thought about using it but then after researching it found that it isn’t necessary for bolt actions (usually) so I decided not to. Some people claimed they saw better accuracy when crimping for their bolts and I thought I could play with it down the road.

Here are 10 loads from this batch (UNcrimped) and one dummy round (CRIMPED). It is obvious the loads I shot today were not crimped. There is a slight ring, but that is from chamfering the outside of the case mouth when I trimmed.

Attachment 43467

I would agree on that, all the marked rounds are not crimped in that photo.

[XC700116]

When brass flows into the ejector you are already pushing it. Primer cratering is not a very reliable indication of pressure.

Yes, my LR rig will crater primers with very light loads and soft primer cups.


Also from what you said about tying to measure the OAL to the lands, I'd try loading a bunch, or just further seating the loads you have to 2.780 to make sure you're not jamming at all. If the pressure signs go away, you have your answer, but continue with caution.

[BuffCyclist]

Your headstamp doesn't start looking like your bolt face because of crimp, undersized primers or loose pockets regardless of what speed you're getting. It's also unlikely they put mag primers in the box. The loads are overpressure plain and simple. My best guess is you're too close to the lands and some of the bullets' ogives are long / inconsistent and jamming the lands. As to speeds, some barrels are just slower than others. If it makes you feel better, my 168 target load averages 2,585 from a 24" Rem barrel and I'm not changing anything. You can try different combinations of components, but you can't tell the rifle what to like. It tells you.

So then how do I explain the 38.0gr load (14th shot) that blew the primer out as well. that is 4.8gr lower than the over pressure load and did NOT show any signs of cratering, ejector marking, etc.