Twist Rate

11 August 2002, 11:35

<AVMcGee>

Twist Rate

Will a 1-10" twist be fine for shooting a 130gr. .308 bullet at 4000fps? Or would a 1-12" or 1-14" twist be necessary? Thanks.

11 August 2002, 11:39

DB Bill

About the only .30 caliber that I know of that will blow a 130gr bullet that fast is the Lazzeroni WarBird...suggest you give John Lazzeroni a call and ask him. Check out his web-site at www.lazzeroni.com as it may have rates of twist for his rifles on that.

11 August 2002, 18:10

<DLS>

That sure is quick.

I had Hart rebarrel a 308 for me a couple of years ago for 150-165 grain bullets and they reccomended a 1 in 12, and it works great for me. I haven't tried anything lighter than 150's though.

11 August 2002, 22:24

RIP

I recall that Lazzeroni used a 12" twist on the Warbird. And they used a 130 grain bullet in it with good results approaching 3900 fps, IIRC. Anyway, a 12" twist would be O.K. with those heavier bullets at high speed as well as the light stuff, more than likely.

What ever happen to the .375 caliber Lazzeroni Saturn? Or, who cares?

12 August 2002, 05:16

Bill Leeper

130s would be easily stabilized with a 15 or maybe even 16 inch twist. You would however, then have a single purpose barrel.It would not stabilize heavier bullets. A 14 will work for up to 168s a 12 twist will stabilize anything you are likely to shoot with the exception of the 220MK. A twist that is faster than necessary may work fine. A twist that is too slow for the bullet will not. Regards, Bill

12 August 2002, 08:56

<AVMcGee>

Thanks for the information.While reading the input here and on the Lazzeroni site another question comes to mind.

Will a 1-14" twist allow higher velocities than a 1-10" twist while using a 130gr. bullet?

12 August 2002, 12:38

<.>

quote:
Originally posted by AVMcGee:
Thanks for the information.While reading the input here and on the Lazzeroni site another question comes to mind.

Will a 1-14" twist allow higher velocities than a 1-10" twist while using a 130gr. bullet?

According to PO Ackley, about 35% of your energy goes into spinning the bullet in the bore. Velocity freaks running extreme loads use smooth bores to get maximum velocity.

Seemingly, a tighter rifling would slow the velocity, but it's hard to predict how much. Sometimes the increased back pressure resulting from a tighter rifling actually results in higher working pressures and velocities.

But you're building something that I don't have any hands on experience with. So it's all armchair speculation on this end.

13 August 2002, 13:05

<AVMcGee>

I talked to John Lazzeroni today. He uses 1-14" twist in his custom rifles. The Sako has a 1-12" twist.

He also told me that a 1-14" would allow more velocity than a 1-10" twist in my situation.

Thanks everyone for your imput.

13 August 2002, 16:38

RIP

Thanks for the info. 14" twist in the Lazzeroni made Warbird. I must have been confused by the Sako TRGS in Warbird having a 12" twist. Sometimers disease strikes again.