M40 barrel twist

[Ted Harte]

Looking to build up a M40 Clone, and would like to use it for longer ranges 500 plus.
.308 of course, 24 " but what twist rate ?
1/10 or 1/12 ?

 

[fdkay]

Looking to build up a M40 Clone, and would like to use it for longer ranges 500 plus.
.308 of course, 24 " but what twist rate ?
1/10 or 1/12 ?

Depends.
Original M40 from remington had a 1-10 twist, once they began to transition to M40A1 they changed to 1-12.
Either is sufficient to stabilize the 175 class of bullets.

 

[Ted Harte]

I'm guessing with handloads either will shoot fine.
Any known reason to change to 1/12 with the a1 ?

 

[Wilderness]

My clone is 1/12, buts that due to the factory sps varmint action/barrel. Haven’t shot at 500, but it does work at 2.

 

[FrontSight79]

Looking to build up a M40 Clone, and would like to use it for longer ranges 500 plus.
.308 of course, 24 " but what twist rate ?
1/10 or 1/12 ?

Found this... not sure the twist but it’s original and bore is supposed to be great... outta my $$$ range.

GunBroker.com - Error

 

[fdkay]

Found this... not sure the twist but it’s original and bore is supposed to be great... outta my $$$ range.

GunBroker.com - Error

Just purchase a good quality 1-10 twist M40 profile, Schnieder is what they went with for the A1.

 

[m1marty]

Just purchase a good quality 1-10 twist M40 profile, Schnieder is what they went with for the A1.

Schneider was very late in the game for the a1. Others such as Hart, Atkinson and HSP were also used.