.240 Weatherby question

[chrisk]

I was looking through Weatherby’s rifles. Said that they are using 1:7.5 now. With the offering of ammo in 75, 80 and 100 is this twist too fast for these ammo offerings?

[fish4food]

I’ve not shot anything below 80 grain out my 6mm, but it’s just a plain Jane 1:7.5 twist 243.

At the Weatherby velocity, I’d think the 100 would be the lower end of their factory load. Curious if they plan on loading anything heavier.

a 115 D-Tac at 240 Weatherby velocity would be sick!

[M16]

Do muzzle velocity times 720 divided by the twist rate to calculate your rpm’s. You need to stay under 300,000 rpm’s for bullet stability and keeping the jacket from coming apart.

[Chase4556]

Do muzzle velocity times 720 divided by the twist rate to calculate your rpm’s. You need to stay under 300,000 rpm’s for bullet stability and keeping the jacket from coming apart.

Going by that, the 72gr Hammer bullet would be a 355,200 RPM.

Something tells me weatherby wouldn’t drop the twist rate to something that wouldn’t shoot the bullets they offer or cause issues. You gotta have Joe Schmoe be able to buy the rifle and buy whatever ammo he saw on the shelf and it shoot well. Otherwise they have a bunch of mad customers that didn’t know any better.

[M16]

Hammer bullets are a different animal. There’s no jacket to come apart. But Hammer recommends a 1-12 twist rate for their 6mm 71 grain bullet.

https://hammerbullets.com/product/243cal-71gr-shock-hammer/

[chrisk]

I believe it’s the Mark V and 307’s that changed their twist. The Vanguard rifles should still have 1:10. If I read it right.