1/10 vs 1/11 in 308

[TiroFijo]

Thanks a lot, KevinB

Is this 1:11 twist suitable for all normal barrel lenghts too (say, 14.5" to 20"+ in a 308)?

How is transonic stability with these barrels? Can you tell us if there are any loads that can go subsonic and maintain good/decent accuracy? If so, which ones (M118 LR, etc.)?

TIA

[Pappabear]

Does anyone have a good explanation for why LMT went with 1/10? Does it have anything to do with 16" or CL?

pb

[rsilvers]

Use the Miller twist formula and look for values 1.50 or more under typical conditions or 1.2 or more under extreme conditions (-20 degrees F and average velocity-(3*standard deviation).

[KevinB]

Thanks a lot, KevinB

Is this 1:11 twist suitable for all normal barrel lenghts too (say, 14.5" to 20"+ in a 308)?

How is transonic stability with these barrels? Can you tell us if there are any loads that can go subsonic and maintain good/decent accuracy? If so, which ones (M118 LR, etc.)?

TIA

We no longer do 14.5" and I have not shot them past 100m. However the 1:11 16" does submoa to 800m, and likley past though I have not personally seen.

This is with both M118LR, and Lapua (167, 170 and 185gr)

[rsilvers]

1:11 in a 16 inch barrel should be able to make stable any supersonic ammo you would shoot from that kind of rifle. I ran the Miller formula for the 175 M118LR and for the Lapua 185 and the values were always over 1.4 - even at cold temps.

For subsonic 1:11 twist, round nose bullets are shorter for their weight, and so you can use heavier ones than if you use pointy bullets. I would look into the 150 - 180 range for round-nose bullets and 150 for pointy bullets.

If I were building a bolt rifle to shoot Sierra 240s subsonic, I would pick 1:6 - 1:7 twist.

I have a 1:4 twist barrel on order, and I will shoot 110s from it and see if they blow up.

[Ring]

1-4?... dam.. who makes it?

[rsilvers]

http://www.pac-nor.com/barrels/

[Thomas M-4]

You can get any twist you want from these guys and its accurate down to +.0001/-.0000
http://www.bartleinbarrels.com/

8-12 month waiting list.