2 Baer barrels, big difference in chrono

[fastarget]

One barrel has 700 rounds through it the other about 2800 rounds through it, both 45, the less used barrel chronos on average 40-50 fps more. I would like to know why? The science.

Is there a correlation between using hot powders (TG) in lots of drills/getting the barrel hot, and premature barrel wear?

[G-ManBart]

There isn't any way to determine why one barrel is faster than another. Take two identical, new barrels off the line, chronograph the same lot of ammo through them and they won't be the same. Rifles show even more difference...there 100fps difference isn't unusual.

I haven't seen anything documeting barrel wear differences with different powders, but the more heat you put in the barrel, the faster it will wear. R,

[fastarget]

Thanks G-man,

Interesting , would using different bullets make a difference, plated to lead etc in your experience? or does the same deviation occur regardless? I did the chrono work trying to come up with a minor load for idpa with 310 and berrys 230.

[Matt Cheely]

I've had brand new barrels from the same lot be 50-70fps different with the same ammo on the same day.

[G-ManBart]

Thanks G-man,

Interesting , would using different bullets make a difference, plated to lead etc in your experience? or does the same deviation occur regardless? I did the chrono work trying to come up with a minor load for idpa with 310 and berrys 230.

Honestly, I have no idea as that's not something I ever tested for. Since so much whacky stuff happens with ammunition, reloading, guns, etc, I wouldn't be the least bit surprised if you had two otherwise identical barrels that were 50fps different with one kind of load/bullet, and nearly identical, or much closer together, with another kind of load/bullet. My sense is that most of the time, the difference is going to be pretty consistent from one type to the next, but I don't really have anything to back it up other than that I've seen pretty consistent differences between two guns regardless of what powder, bullet, etc I used in them. R,

[pjb45]

My Nowlin barrel has probably over 60,000 rounds through it. My load is the same from round 1 to round 59, 900. The average velocity is statistically the same. I would suggest the issue is not related to use.

[fastarget]

My Nowlin barrel has probably over 60,000 rounds through it. My load is the same from round 1 to round 59, 900. The average velocity is statistically the same. I would suggest the issue is not related to use.

I can agree with that, my 40.with Shuemann barrel is still consistant over thousands of rounds.

[Sean Gaines]

your lead/Molly coated bullets will be faster bar none!

[Whoops!]

I would think this phenomena relates mainly to chamber inconsistencies (length from bullet to rifling, etc.) and how the powder igniting moves differently around the bullet and through the barrel with initial detonation.