Shooting 140 grain projectiles?

Has anyone had experience with barrels from Lawton Machine in
Dillon, MT?

Dan makes a good tube. Check his reference for your requested info.

http://www.riflebarrels.com/products/caliber_twist_rates.htm

Good luck, welcome to the Fire.

Also, I have no experience with Lawton Machine.

Thanks for the link, I had gone to their website but I had failed to scroll down to the bottom chart! Thanks... 10 seems to be the answer.

I've noted that some 7mm cartriages have 9 inch twists for the best stability w/ the longer 175 gr. bullets.
I'm told that a 10 inch twist may stabilize those bullets in a .280, or it may not. E

Have had a number of 280's and shot out two. Go with the 9 twist for the 140's.

I have a 7-MM Rem. mag. it has a Shilen #2 contour and a 9 twist. This gun will shoot 140s just fine.

Ive got a 7mm-08 that tack drives 140 grainers and is a 1:10 twist rate.............

A 9 or 10 twist is probably the best bet, but on the campfire, it won't shoot unless it's an 8 twist

My only 7mm is a 7-08 and it has a Shilen 10 twist and it shot everything up to and including 168 Sierras just fine.

The 7mm-08 is normally about 1:9 ( 1 revolution in 9 inches)

The .280 Remington normally is 1:9.25, but the range is from 9 to 12. 1:10, just like a .270 Win or .30-06, works fine with a wide range of bullets.

The 7x64mm, which is about the same as a .280 Remington is 1:8.66, but it originally was designed for the 175-gr spitzer bullets.

The 7x57 originally was 1:8 for 175-gr bullets, because its forward speed was slower, and needed more rotational velocity to stabilize the bullets of its day. You cannot just extrapolate any 7mm cartridge to another one. A 7mm STW might do better with a 1:12 rate.

A 1 in 10 should work fine for most 140s. But longer ones like the berger just might be better off with a 1-9.5. On hunting rifles it is always better to err on the fast side so 1-9 would be my choice, and then your good for everything up to the 180s. People trying to get the last fps might go the other way like a 1-11 or even 12 but I wouldn't recommend it.

Some people theorize that a faster twist increases terminal performance-straight line penetration, more destructive, faster expansion etc. etc. all of which is almost impossible to verify.

A 1-10 will work easily. I have had a 7mm-08 and a 284, both with 10 twists. They were both very accurate with 162 Hornady BTSP's, so 140's are easy.

That said, a 9 twist may be even more of a good thing. My present 280AI and 7Rem Mag are both 9 twists, and both are very accurate with 120-162 grain bullets. The 280AI in particular will positively stack 140 accubonds at 3150 fps.

9 or 10, either is fine.

Will a 1-10 be OK for a 7x57AI w/160gr Partitions.Thinking about taking mine on an elk trip. powdr

powdr..if you have barrel twisted as such 1 in 10..just take it to the range w/160gr partions and see for yourself..it could be just fine

1:9 twist is great in the 280 Rem...

Just ordered a Hart in 280AI two days ago. Hart recommended 9" twist for bullets above 140 grain. If velocity of the 7x57 AI is lower than the 280 AI 10" twist may work. There seem to be no rules for what will work every time.

1:10 will easily stabilize the 140 gr .284 bullet. If you ever
plan on shooting 160-175 grs, you may wish to look at a 1:9 rate
of twist. Of couse, it does matter which bullets you shoot.
For instance, a Barnes TSX 150-gr bullet is as long as a Hdy
175-gr bullet. Obviously, 160 & 175-gr Barnes TSX bullets are
longer yet. The additional length, depending on velocity, may
or may not stabilize w/1:10 rate of twist. Frankly, I've not
experienced any problems with the 160-gr TSX or the 168 VLD
bullets in my 7x57 that has a 1:10 twist. OTOH, my 280 Rem has
a 1:9 twist. Both rifles are tack drivers and produce sub-MOA.

If you're shooting Berger 180-gr VLD bullets, you might want to
consider a 1:9 twist.

As a side note, both my 7mm barrels (7mmTCU & 7-30) for my T/C contender have a 1:9 rate of twist probably due to the lower velocity.