6br barrel lenght

[JamesinAsheville]

I'm putting out the fleece here in regards to barrel lenght. I have a 1-8 twist that will finish at 30". I was going to finish it at 28". Will the extra 2" add anything but weight?? Thanks

 

[Rustystud]

James:

John Skowron in Raleigh, is shooting a 6mmBRX. He is shooting a 32" inch barrel. He is getting 3080 fps with a 107 Berger. The 6mmBRX is running 32.5 grains of Varget with a 9 fps ES. He has upped the load to get as much as 3100fps.

I am sure some 6BR shooters can give you an answer on the 6mmBR that shoots about 3. grains less powder.

Rustystud

 

[jb1000br]

I run a 28"

30.8gns Reloader 15 gets me ~2915fps with 105Sc/106CR

30" would probably get me no more than 2935 according to the testing Jackie Schmidt did for us several months ago.

MODERATOR: In that test we cut down a barrel from 33" to 28" in 1" increments. Powder was a "practical max" load of VV N140. Total velocity reduction from 33" to 28" was 40 fps and the speed loss was pretty much a straight-line 8 fps per inch.

N140 is one of the faster powders for the 6BR. Conceivably, with a slower powder,that burns farther down the barrel) you might see a bigger change. But I doubt you'll get more than 25 fps more going from 28" to 30" and it might be a lot less.


JB

 

[JamesinAsheville]

Thanks Guys...I thought it would not be much gain for the 2 extra inches. Proubly make it a 28" and that will make it balance better too.. Thanks again

 

[Rustystud]

James and Paul:

I am rebarreling Johns'second 6mmBRX it will also be 32" Broughton 1:8, 5C. John wants me to setback his first 6mmBRX from 31.750. I will probably bring it back to 28.. It will be interesting to see what velocities he gets. I am going to bulid him a magazine box for the 6BRX so he can shoot it Cross the Course. We are also very interested to see what barrel life he will end up with.
Rustystud
a/k/a Nathaniel G.Lambeth, Sr.
Custom Guns and Ammunition

 

[12man]

On the topic of barrel length, what would you expect to lose in velocity comparing 26 to 24 to 22 inches on a standard 6BR. My primary use of this is a carry type varmint rifle. Thanks

 

[JamesinAsheville]

12man.. the best I can tell would be approx.20-30fps per inch of barrel lenght. so if you went from 26"@ 2900fps to 22" it would drop to somewhere around 2800fps. Hope that helps.

 

[12man]

Thanks building a carry varmint gun, trying to keep the weight down & good balance to without losing alot of velocity

 

[Shooter32]

Go with the longer barrel and have it fluted to reduce the wieght !! :thumb:

 

[Pbike]

Looking at speed loss due to going with a shorter barrel is like comparing apples and oranges.

If you have 22 inched to produce "x" amount of speed, you need "Y" amount of pressure to build in "Z" amount of distance or time. On the other hand, if you have 28 inches to try to get the same "x" speed, you need the same "Y" pressure, but you have "Z" time plus 6 inches. You can do so by changing burning rate of powder in most instances.

Paul

 

[2644ever]

James, I would keep it as long as possible, just for the same reason you guys invited Concord to land on your Municipal Airport 20 years ago: Speed is everything and the best poor man's magnum is a loong barrel. Plus when the throat starts to walk out on you, you can cut the chamber and still get 28" left!
Take Care.

 

[JamesinAsheville]

Yep, it ended up being 30". That was my thought 2644ever. You never know. Almost ready to start the barrel breakin. Yep ee.