PDA

View Full Version : Bushmaster Varminter


IdahoG36
July 16, 2007, 03:06 PM
I recently purchased a Bushmaster Varminter with a 24", 1/9 twist barrel. My question is this- How heavy of a bullet will the 1/9 rifling stabilize? I am wondering if 75 or 77 gr bullets will stabilize in this rifle for long range shooting.

FS2K
July 16, 2007, 04:46 PM
The 1:9" twist it ther happy nedium of AR15 barrel twist rates, and are able to stabilize anything from 45 gr. to 72 gr. though I think 72 gr. is the heaviest anyone can expect that twist rate to stabilize.

The majority of stuff I shoot (out of my 1:9 barrels) are M855's (62 gr.) That's not saying that I believe 62 gr to be the heaviest bullets for an AR with 1:9 twist, but I supposeI'd draw the line at 72 gr. Based on nothing but more than what I noticed while shooting. I have a couple of USGI magazines with 77 gr Sierra Match rounds for my FN FS2000 (1:7) I hope this helped.

Lexter
July 16, 2007, 07:58 PM
From The Ammo Oracle:

"At typical .223 velocities, a 1:9 twist will stabilize bullet lengths equivalent to lead-core bullets of 40 to 73 grains in weight."



Lex