6.5BR Twist Rates

[sling_n_glove]

Hey folks,

I'm trying to get a 6.5BR rifle project rolling but the 6.5BR rifle shooters seem to all be someplace other than this forum. I haven't found them yet. I've been trying to figure out the best twist rate to get started with. Certainly there's not much harm in erring to the fast side but I also want to find out where the margin is for best performance with bullets in the 120, 130 and 140 grain categories. I know people like 8" twist barrels, but has anyone used 1-in-9 barrels for 6.5BR velocities? 1-in-8.5?

 

[vmthtr]

I am using a 65 br in an XP 100 for IHMSA shooting. I am using a 8 twist for the 140 SMK. Shoots way better than I can do justice for.

Mike

 

[Johnsmith]

I have a 6.5mm BR with a Krieger 1 in 8 twist barrel, 28 in long. I have not shot it a great deal but it seems to be shapeing up well. I am using Lapua 123 gn boat tail projectiles and I would think 2800 fps is acheiveable. If so I would stick with this projectile as a 140 gn bullet needs to achieve 2700 fps to perform at a higher level. That velocity may push the enveloppe a bit too much on the 6.5 BR
To further clarify an answer to your question, I think that a 1 in 8 twist barrel would be neccessary considering the lower velocity of the 6.5 BR
John

 

[olympian]

I would not bother trying anything other than a 1-8" twist if you intend on shooting 140gr boattails. The 1-9" or 1-10" would be great if you stick to 120gr and less bullets.

 

[RickB]

I agree with the recommendations to stick with the eight twist barrel if you want to attempt shooting 140 grain class bullets. I do think that 2,800 fps is a rather overly optimistic velocity goal for a 6.5 BR though. I can not readily think of anyone I know shooting one in a rifle length barrel who has mentioned a velocity approaching 2,800 fps. I tried one variation on an improved 6.5 BR briefly, but it did not achieve my expectations for velocity. One person I know has shot a 6.5 BR given the Ackley treatment who reported achieving velocities between 2,750 fps and 2,800 fps, but he is known to shoot loads that are sometimes one the warm side of things.

All who have shot the 6.5 BR with whom I have spoken were pleased with its accuracy. If 2,800 fps is essential for what you have in mind you may want to explore some larger capacity cases.