Trouble reducing velocity spreads.

[Bang4theBuck]

I built a 22 Creedmoor and the rifle shoots ver well with 75 ELDM, 80.5 bergers and 85.5 bergers, however, I have struggled a bit with reducing velocity spreads. I have run all three bullets with H1000 and RL 26. I'm using CCI 450s, which have produced very tight ESs in other creedmoor cases. I am getting over 3550 for velo with the 75s with no signs of pressure, but the ESs have been in the 40 fps range. I am using Forster benchrest dies. Initial neck interference fit (neck tension) was right at about. 0015". I reduced the size of the expander ball by .001" to try to increase consistency, but it didn't yield any improvements. Wondering if anyone is running this combo or has any other suggestions on next steps to reduce Velocoty spreads.

 

[Dmagna]

I run 85.5s with rl26 at 3300, I have a 1-7 twist so this is actually probably over max. I havnt lost any bullets yet but i probably will once the barrel starts to burn out. I anneal frequently and have .002 neck tension.

 

[Koda_]

I would try annealing.

 

[Bang4theBuck]

The brass came annealed (Alpha) and the loads that I am speaking of are only the second firing. I anneal religiously, but only every other firing. In light of that, do you still feel this could be a contributor to the issue?

 

[ButterBean]

I'd Increase the neck interference a bunch,
003 and see what happens

 

[ButterBean]

The brass came annealed (Alpha) and the loads that I am speaking of are only the second firing. I anneal religiously, but only every other firing. In light of that, do you still feel this could be a contributor to the issue?

I wouldn't think so

 

[26Reload]

What chronograph are you using...

 

[Bang4theBuck]

Garmin xero
chronograph.

 

[Bang4theBuck]

I'd Increase the neck interference a bunch,
003 and see what happens

I am running .0025 to .003" now....are you suggesting .003" more?

 

[ButterBean]

I am running .0025 to .003" now....are you suggesting .003" more?

No I'd say that's tight enough, do you have a different primer you can try?

 

[can1010]

being your only on your second firing with new brass and alpha being a pretty hard brass you might be just getting fully formed to your chamber and the spreads should start to come around. if not consider primer change that was already mentioned or less neck tension

 

[RegionRat]

I agree with experimenting with the brass prep and neck tension details above, and in addition just food for thought...

Does this rifle shoot any other loads and produce a small speed variation?
If it does, then disregard the following since this would exonerate the ignition system.

If it doesn't, have we checked priming details or tried other primers?
Have we checked the ignition system for any defects or a weak firing pin spring?
Is there excessive headspace?

Primers and how we set them off can be half the battel when it comes to poor speed stats.

This concept includes defects of the actual primers, their installation, and the firing pin performance.

If the bolt maintenance is neglected, or if there is a mechanical defect that causes erratic friction, the ignition can be responsible as often as the brass prep or recipe.

If playing with the brass prep or recipe doesn't improve, I would have a hard look at the firing pin spring and parts.

Sounds like a screamer of a rifle. Good luck and have fun.
Merry Christmas.