7mm 140-gr twist rate

[hemiford]

Thinking about buying a 7mm barrel for my 7RM to be dedicated
to only lighter 140-grain bullets. I believe in this case that the
common 1:9 or 1:9.25 twists are not necessary.
While I think 1:10 would work, what about 1:11 ?
Some barrelmakers even offer 1:12. What 7mm bullets would one
shoot using a 1:11 or 1:12 twist ?

 

[EricL]

Check out berger twist rate calculator.

 

[Alaska2006]

Yup, what Eric said or any barrel builder will tell you what twist for your desired projectile weight.

 

[MudRunner2005]

I know this might sound strange coming from me, since I'm a huge 7mm fan, but you would actually get better performance from a .264 WinMag shooting 140's, than you would shooting a 7mm with 140's. You can also reuse your 7mmRM brass, as they utilize the same case.

And if you ever plan to shoot heavier, Matrix makes a 160gr 6.5mm bullet that I have heard is excellent for hunting and target. You will need a 1:8 twist.

 

[hemiford]

Mudrunner,
I think your idea on the 264 is an excellent one, I didn't think
along those lines. If I'm buying a new barrel anyway, it could
be in 264Win. Only possible drawback would be getting into
an additional caliber to keep inventory for.

I was just reading the thread on the Nosler 120-gr red tip 7mm
bullets. People seem to be having good results with those, they
would have less B.C. and distance potential than 140's of course.

I'll chew on it for a while, but I'm gravitating towards keeping
to the 7mm over the 264. I have another 7-RM with a long barrel
that gets 168 and 175 grain bullets, and a 7-STW in the works.

*************

Berger's calculator likes 1:10 for their 140-gr hunting VLD.

 

[Predator 22]

I inherited a 7x61 Schultz & larson from my dad that has a 1:12 twist rate. It will stabilize up to 150grn flat base bullets.

 

[Bart B]

I'd stick with the 7 RM as it has about 30% more barrel life than a 264 WM.

A 1:11 twist would probably be most accurate with 140's.

 

[MudRunner2005]

I'd stick with the 7 RM as it has about 30% more barrel life than a 264 WM.

A 1:11 twist would probably be most accurate with 140's.

If he's pushing the same weight bullet to nearly identical speeds out of the same case, and the only difference is 0.020" in diameter, I highly doubt he will see remotely near a 30% barrel life increase.

Now, if you were comparing 168-180gr bullets out of a 7mmRM going much slower than a 130-140 out of a .264 WinMag, sure, I would agree that there is probably a 30% increase in barrel life there, but not when you're comparing similar weights and cases, and only difference is .020" in bore diameter.

 

[7stwnut]

I have a STW with 26" Shilen 1 in 11 twist and it loves the 140 interbonds and Berger 140's it does not shoot the 168 Bergers worth a hoot. Good luck!