Can someone explain what’s going on here? I just took off a Criterion 20” 6 Creedmoor barrel that was shooting the factory 103 ELDX at 2870fps and installed a Proof Research 24” 6 Creedmoor barrel and just shot the same lot of ammo over my magnetospeed and 2860fps. Everything on the rifle is exactly the same except for the barrel. Temps are pretty much the same from the 20” barreled chronograph day to now. Did I just waste my money on a proof barrel?
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4” longer barrel but same fps???
- Thread starter pyplynr
- Start date
Were they chambered with the same reamer? If not, segregate some fired cases from each barrel, and take careful shoulder, base, and headspace measurements of each. May have some chamber variances.
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Is it the same twist rate? If you went with a faster twist on the Proof that would partially explain it. My bet would be twist rate or the factory ammo you are running. It just doesn't like that barrel. If you were reloading for it it would be easy to test this.
You should be seeing more MV even on just 4" if everything remained the the same.
You should be seeing more MV even on just 4" if everything remained the the same.
The reason I ask is, I see a lot of problems with carbon ring.
People think they clean the barrel regularly, but it's not enough to clean a carbon ring build up properly.
You won't believe how many people don't believe it till they put a bore scope down their tube.
With only 185, don't know if that's the problem, but worth looking at.
Between that and a new barrel that will speed up, and what has been mentioned above.
Just giving you options.
People think they clean the barrel regularly, but it's not enough to clean a carbon ring build up properly.
You won't believe how many people don't believe it till they put a bore scope down their tube.
With only 185, don't know if that's the problem, but worth looking at.
Between that and a new barrel that will speed up, and what has been mentioned above.
Just giving you options.
OP,
There are multiple variances that can create higher/lower velocities.
Biggest thing effecting velocity is probably the chamber. It can effect pressure which in turn effects velocity. Things like bore diameter and land/groove size effect velocity more often then anything else. Being two different brands of barrels there’s probably a significant difference in both. If the Criterion has given those speeds from the beginning then it’s most likely not a carbon ring.
As the others have said, your proof will probably speed up after a few hundred rounds. If it doesn’t speed up I’d throw the 20” Criterion back on. My bet is it’s lighter anyway then the 24” carbon barrel.
There are multiple variances that can create higher/lower velocities.
Biggest thing effecting velocity is probably the chamber. It can effect pressure which in turn effects velocity. Things like bore diameter and land/groove size effect velocity more often then anything else. Being two different brands of barrels there’s probably a significant difference in both. If the Criterion has given those speeds from the beginning then it’s most likely not a carbon ring.
As the others have said, your proof will probably speed up after a few hundred rounds. If it doesn’t speed up I’d throw the 20” Criterion back on. My bet is it’s lighter anyway then the 24” carbon barrel.
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