Priming issue

[Painterbolt]

Got some brand new alpha brass, came from lapua. orginally with lapua I was loading 43.2 grains of shooters choice precision powder with 200.20 bergers with out issues. Dropped my load down to 42.8 grains with the new brass and got what's in the picture. Doesnt seem to be the standard blown primer. Any ideas?

Ran the labradar and I was getting an es of 8. So figured if I was running a hot load my numbers wouldnt be that good

 

[Painterbolt]

 

[spife7980]

Looks like its a leaking blown primer. Back down your charge weight.

 

[918v]

How much does your Alpha case weigh vs Lapua?

 

[Painterbolt]

How much does your Alpha case weigh vs Lapua?

Not sure but just by feel, it's going to be heavier.

 

[918v]

Heavier means less capacity and more pressure. This is especially important when loading heavy for caliber bullets at max pressure close to the lands. You did not reduce the load enough.

 

[Painterbolt]

The odd part is the portion of the primer between the two burn marks. Ya just dont like loosing 50 fps but owell

 

[chevy_man]

Just as an FYI, I find that with some barrels/bullet/powder combos I only get good sd's from the hot end of the spectrum.

Essentially sd's aren't anything to measure "hotness" from. Every rifle will be slightly different. Velocity, and other pressure signs are more important.

For what it's worth, I stop when the primers are flat up to the edge. If I can't see any rounded edge anymore I back down and try different powder.

 

[Steel head]

New brass/brass change=new load work up.

 

[Doom]

This looks like SRP brass. What primer?

 

[Painterbolt]

So after talking to one of the experienced local shooters and Alpha Munitions I have found out the cause. Alpha makes their primer pockets tighter than most and priming new brass you have to make sure that the primers go in perfect. Primer caught the edge and folded over causing it to leak against the sides.