Posted: 4/27/2007 12:28:51 PM EDT
| I just ordered a A-4 Varmint with the 20" barrel. I see that it is a 1 in 8 twist. What bullet weight will be the best ? ( for longer distances ) thanks |
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Steve, Has RRA done any extensive research on what bullet weight works best in their rifles? I know this topic has all sorts of opinions, but any chance RRA has some numbers to validate what works the best in the various barrel lengths? (I'm most interested in a .223 carbine, 1 in 9 twist) thanks, Dan |
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Dan. No extensive independent testing as the caliber, twist rate, bullet weight numbers are all subject to the same laws of physics, regardless of brand and when the numbers were run. In general terms, the faster the twist rate (in a given bore diameter) the longer the bullet it will stabilize. The opposite holds true also. The faster twists will not stabilize a shorter bullet as well, and can actually destabilize it. Also, the faster the rate of twist, the greater the RPM of the projectile. This comes into play with lighter bullets with thinner jackets. A thin-skinned bullet may shed that jacket in flight and the bullet itself can "vaporize"...generally out of a barrel with a twist rate that is too fast for that projectile. Powder type, load, and projectile velocity will also effect overall performance as well. So, two projectiles of the same mass are not necessarily equal in terms of what barrel they will shoot through with the best accuracy. That's why manufacturers of barrels (and uppers and rifles) and bullets, will generally provide a range of bullet weights for a given bore and twist, and why powder manufacturers list a range of loads with different powders...many specifying appropriate twist rates for a particular load. Hope that helps. Steve/RRA |