I did some load testing the other day with my 308 subsonics. It's a 24" 1:12 twist. I'm using 180g Hornady SP interlocks, Trailboss, lapua brass and CCI 200 primers. The flash holes are not drilled out, nor are the bullets lubed.
I'm experiencing a first round drop (2-3" low) with all loads tested. My chrono showed that these were around 100-140fps slower than the last four rounds tested. There was no key hole groups, just drop in velocity. I would shoot the first group, then wait around 7-8 minutes and shoot the next (5 rounds in total). I'm guessing the after the first round the barrel warmed, which is telling me I might need to use lube on the bullets. Even the rounds that were supersonic in the 1200FPS range were having a first round drop issue.
The group I settled on is 1017 fps average and is plenty accurate and again, no key holes. I'm concern about throwing the suppressor on with the first round shot dropping that low. Is a baffle strike possible with that first round shot or will it just continue to be low? Perhaps it's time to dip these babies in crisco.
Thoughts?
I'm experiencing a first round drop (2-3" low) with all loads tested. My chrono showed that these were around 100-140fps slower than the last four rounds tested. There was no key hole groups, just drop in velocity. I would shoot the first group, then wait around 7-8 minutes and shoot the next (5 rounds in total). I'm guessing the after the first round the barrel warmed, which is telling me I might need to use lube on the bullets. Even the rounds that were supersonic in the 1200FPS range were having a first round drop issue.
The group I settled on is 1017 fps average and is plenty accurate and again, no key holes. I'm concern about throwing the suppressor on with the first round shot dropping that low. Is a baffle strike possible with that first round shot or will it just continue to be low? Perhaps it's time to dip these babies in crisco.
Thoughts?
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