Alpha Brass - light primer strike

[opus56]

Hey everyone...

Thought I’d run this by you guys and see if you had any thoughts. I’m working on load dev and just getting 100 or so rounds through the new Benchmark 6.5CM barrel (Impact 737 prefit). The action has fired 3704 live rounds and prob add 2k dry fires. I took apart the bolt to inspect and clean it. Everything looked good. Rest of the rifle components are two-stage Triggertech Diamond trigger, and everything sitting in an MPA BA Comp chassis.

I bought new Alpha SRP 6.5CM brass and am using the same components I used in my last barrel, other than switching from Lapua to Alpha brass. I use RL-16, 140 ELDM’s, and CCI-450’s.

Out of the first 150 I’ve loaded, 28 have failed to fire. I’m using an RCBS hand primer and seating the primers in the Alpha brass is a chore compared to Lapua. But I feel like I’m getting the primer seated properly…never had a round not fire using the Lapua brass (3704 rounds before I finally pulled the barrel).

The primers are from a box of 1000, of which, 200 were used for the last 200 rounds shot through the rifle before the barrel swap...which leads me to think it's not a primer lot issue, but I suppose it still could be.

I’m planning on loading some rounds with the Lapua brass to see what happens, and prob try some factory ammo as well. Any other ideas?

When it shoots, it shoots really well…no issues from an accuracy perspective.

Thanks!

First pic shows: Left is a successfully fired round, center a loaded round, and right is a round that did not fire.

Second pic shows: left, successfully fired round, right failed to fire.

Third pic showing primer seating depth on a failed to fire round (left) and non-fired, loaded round (right).

 

[straightshooter1]

Sounds like something different with the new barrel???

Have you compared the headspace you now have with what you had with the old barrel?

 

[opus56]

Headspace was checked w/ go, no-go gages both before the barrel was removed, and after new one was installed.

 

[Supersubes]

Headspace was checked w/ go, no-go gages both before the barrel was removed, and after new one was installed.

But you changed brass, you should probably check virgin headspace of the brass versus fired head space with the same brass.

 

[opus56]

Virgin Alpha measures 1.552" and fired is 1.561" out of new Benchmark barrel.

Virgin Lapua measures 1.554" and fired is 1.559" out of old Proof barrel.

 

[straightshooter1]

Any difference in the primer pocket depths?

 

[spife7980]

They don’t fire with a second hit?
If you jam a bullet to keep the smaller virgin case from bouncing around the .009 larger chamber, will they fire?

 

[opus56]

Pocket depth w/ my calipers read .121" for Alpha and .122" for Lapua.

No, they don't fire w/ a second or third hit.

I haven't tried seating a bullet longer. I could give that a try.

One thing I am noticing now as I'm watching closer when seating the primer, the plastic guide on my RCBS hand primer shows some wear. So much so, that the case tilts as the primer is seated because of how hard I have to squeeze the lever to seat the primer in the very tight pockets. To get them seated, I'll press the primer in, then rotate the case and press again. Could it be possible that on the initial seating of the primer, it going in a bit sideways, could break up the primer causing it not to ignite?

 

[straightshooter1]

Pocket depth w/ my calipers read .121" for Alpha and .122" for Lapua.

No, they don't fire w/ a second or third hit.

I haven't tried seating a bullet longer. I could give that a try.

One thing I am noticing now as I'm watching closer when seating the primer, the plastic guide on my RCBS hand primer shows some wear. So much so, that the case tilts as the primer is seated because of how hard I have to squeeze the lever to seat the primer in the very tight pockets. To get them seated, I'll press the primer in, then rotate the case and press again. Could it be possible that on the initial seating of the primer, it going in a bit sideways, could break up the primer causing it not to ignite?

Pocket depth is fine. I asked to see if maybe there was an issue with getting the anvil seated properly. And now that you mention what's going on with your seating, I don't think is would break up the primer much but maybe doing something to the anvil???

That long headspace for virgin brass doesn't sound good to me, but . . . I've never had or come across anyone else who's had this issue. Now that you've got some once fired brass, you might test them to see if the problem persists???

 

[Jordanwickham]

Alpha primer pockets are tights as hell but I don't see how that would cause a misfire. I haven't had any misfires with it but I did have some primers get fucked up but I caught it when it happened.

 

[Jordanwickham]

I had a thread on misfires here a few months ago. I was using new lapua brass and cci 450 primers. I was running about a 30% failure.
Turned out I wasn’t seat the primer deep enough. The 450’s need to be set deep enough that the cup is flattened somewhat.
Once I did that with mine I haven’t had a single misfire.

That could explain my no misfires. I use 205m primers

 

[wapiti16b]

Alpha brass(7SAW),205m primers and a Forester CoAX press primer seater about 400 rounds so far and no light primer strikes so far. I should mention I stopped using a hand seating primer tool when my hands became to arthritic . Alpha pockets are tight ! as previously mentioned.

 

[Sixfivesavage]

Had this issue with the same brass and primers and chambering. I almost guarantee that you didn't have the primer fully seated and the firing pin seated the primer deeper when it struck. They won't go off on subsequent attempts. The pockets are super tight on that brass and that's all I can figure out.

 

[opus56]

Update...

Thanks for the feedback and info everyone. It's much appreciated.

I pulled the primers from the rounds that didn't fire to see if they had been damaged when seating and they looked good. So with the little daylight I had last night, I loaded up 10 of the 1x fired brass (FL resize, bump shoulder 2 thou). I also loaded 5 virgin cases but loaded the bullet just shy of the lands to ensure the firing pin can reach. All 15 rounds fired as expected...previously I'd see 3-4 of the 15 not fire. I know it's a small sample size, so I'm planning on getting more rounds loaded today and hopefully try them out tomorrow. The .009" growth of the virgin brass to a 1x fired case might be my issue, so I'm hoping after the first firing this all goes away...and I'll just load the rest of the new brass w/ the bullet at the lands.

 

[Milo 2.5]

Update...

Thanks for the feedback and info everyone. It's much appreciated.

I pulled the primers from the rounds that didn't fire to see if they had been damaged when seating and they looked good. So with the little daylight I had last night, I loaded up 10 of the 1x fired brass (FL resize, bump shoulder 2 thou). I also loaded 5 virgin cases but loaded the bullet just shy of the lands to ensure the firing pin can reach. All 15 rounds fired as expected...previously I'd see 3-4 of the 15 not fire. I know it's a small sample size, so I'm planning on getting more rounds loaded today and hopefully try them out tomorrow. The .009" growth of the virgin brass to a 1x fired case might be my issue, so I'm hoping after the first firing this all goes away...and I'll just load the rest of the new brass w/ the bullet at the lands.

If you have a lot more new brass to fire, go to a softer cup primer for the initial firing, Fed 210, CCI 200. The 9 thou growth is the issue as you may know now.

 

[opus56]

Ordered the Lee Auto Bench Prime yesterday from Amazon and got it today. Saw Gavintoobe using one with his Alpha brass so I figured I'd give it a go. Gotta say it works really well. Much easier than the hand primer but still very easy to feel each primer seat.