JPK
(.375 member)
30/12/08 05:46 PM
Re: 500/416 experience's

On the M16, I had a nice long response regarding the current 1:7" twist, as you note required by the tracer ammo designed to compliment the Belgian developed Nato ammo. It was lost to the "no longer valid" deamon that appears when you take too long to post.

Suffice to say that the original 1:12" stabilized the original bullet in air, in moderate and hot temps. But it was short stabilization in arctic cold conditions, I suppose because the ammo was slower in really cold conditions, lowering rotation speed. (Recall that velocity directly effects rotational speed and stabilization, with greater velocity producing greater rotational rate and more stabilization and less velocity the opposite.) It's apparenty marginal stabilization in other conditions lead to rapid tumbling in denser mediums than air. Also leading to the complaints regarding penetration limitations in all mediums, with special concern regarding body armour.

The Belgian ammo Nato adopted now faces complaints of penciling, or too straight line, over penetraion because it is over stabilized.

I'll provide cites if you want them. I think a review of the fast twist = greater penetration threads gets us to the same place. That being sufficient but marginal stabilzation in air = poor penetration and tumbling in denser mediums and greater stabilization, even "over stabilization", leads to reduced early bullet yaw as well as to greater penetration independent of early yaw considerations. The latter point regarding greater penetration being open to some debate. I'm a beleiver though.

JPK

JPK



Contact Us NitroExpress.com

Powered by UBB.threads™ 6.5.5


Home | Ezine | Forums | Links | Contact


Copyright 2003 to 2011 - all rights reserved