Twist rate + 458 Lott

[Andrew NOLA]

I am considering rebarreling a 458 WM to 458 Lott. I would use primarily 450 and 500 grain copper bullets in it - Barnes TSX and North Forth Cup point solids

I know they come in 14 twist but I am considering a 12 twist Lilja for the longer copper bullets to help with stabilization and accuracy.

10 twist is also available.

What have others tried and what were the results?

Thanks very much

 

[USMA84DAB]

Art Alphin spec'ed the .495 A-Square at 1:10. The higher the spin, the more momentum to remain stable/the more difficult it is to de-stabilize the bullet as it penetrates. He was convinced that the higher spin rate would get straighter penetration/less propensity to curve off the line of penetration.

 

[Andrew NOLA]

I have found some more articles on here (Thanks, Micheal458). In the light of day, it seems that going from 458WM to 458 Lott today is not really much gain.

I might revisit this but am going to work on handloads and see what results I will get with the WM. I would like a faster twist exactly for the reasons stated above, but dont know that the squeeze would be worth the juice

 

[Hunter4752001]

If you're set on using monos then going with Lott is a better answer. The all copper projectiles are much longer than equivalent weight and therefore take up much more space in the case.

As far as twist rate goes I don't think you'll have a problem with the standard 1:14" twist. I use 450g monos and have no issues with stability. However if you need reassurance, get the specs for the projectiles you want and put them into any of the stability calculaors available on-line.

 

[skydiver386]

To much is better for stability than not enough, both for accuracy and terminal penetration when the bullets strike flesh. The standard 1/14 twist is fine for lead core bullets, but I think a faster twist is nearly always better for Barnes X and other mono bullets. I'd go with the 1/12.

 

[cajunchefray]

I have found some more articles on here (Thanks, Micheal458). In the light of day, it seems that going from 458WM to 458 Lott today is not really much gain.

I might revisit this but am going to work on handloads and see what results I will get with the WM. I would like a faster twist exactly for the reasons stated above, but dont know that the squeeze would be worth the juice

Pierre van der Walt has a nice discussion about twists rates and terminal performance in his book , African Dangerous Game Cartridges. Faster twist rate is better for terminal performance.
I conjecture that is one reason that the 416 Taylor, with 1:10 twist rate was considered effective.

The physical science he explains is detailed, but the concept is simple, run the drill bit faster and easier to get a straight hole.

 

[Nhoro]

I have a 458 win mag reamed to Lott and use Peregrine copper 515 gr solids and softs. No problems with stability. That is in a standard CZ 550. The Lott case allows me a bit more space and a larger variety of powder because of it. But I have used the win mag cases with bullets loaded out to longer OAL. The monometal bullets allow it quite easily with their driving bands.in addition, the 450 gr bullets are excellent in THE win mag. No real need to re barrel for faster twist or any real née for more penetration than you already get. They already penetrate more than the Nitro Express calibres of old.