perrytrails
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Just purchased a Rem 700, 308 with a 1 in 11 1/4 twist. What bullet weights would stablize the best for this twist rate?
Reloading 308 questions
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rockstar.esq
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I'm going to take a stab and say that 168 grain and below will be happy times for you. But honestly I'd bet that anything from 150 to 180 will work just fine. I shoot a 1 in ten with 168 grain Sierra HPBTs that will group sub 1/4 MOA on occassion. If you haven't tried IMR 4895 in this caliber you might find as I did that it's a great match because velocities are fairly consistent across powder charges so you can really make gains in accuracy there.
perrytrails
Member
Thanks, I'll give them a try.
rbernie
Contributing Member
150gr-155gr will likely work best.
jaimeshawn
Member
from over in snipercountry:
"Gunsmiths generally use the Greenhill Formula to determine the optimal twist for a given bullet. The formula is T=150(d/r) for velocities from about 1500 to 2800 fps. Substitute 180 for the 150 value for velocities exceeding 2800 fps. "T" is the twist rate. "d" is the bullet diameter. "r" is the bullet length to diameter ratio (length of bullet divided by diameter). In .308, it works out fairly well. Sierra 168 grain Matchking is 0.308 inches in diameter. Bullet length is about 1.210 inches so we have a length to diameter ratio of 3.929. Plugging this value into the formula and using the 150 constant (the proven best velocity for the 168 grain MK is 2550 - 2600 fps), we get T=150 x (.308/3.929); T=150 x 0.078; T=11.76 inches or 11 3/4 inch twist …. One rotation of the bullet for every 11.76 inches of barrel traveled.."
http://www.snipercountry.com/hottips/TwistRate.htm
A faster twist rate like my Ruger M77 (1:10) really sings with heavy bullets.
It likes the 200gr Sierra Matchkings - It's a very very good bullet.
"Gunsmiths generally use the Greenhill Formula to determine the optimal twist for a given bullet. The formula is T=150(d/r) for velocities from about 1500 to 2800 fps. Substitute 180 for the 150 value for velocities exceeding 2800 fps. "T" is the twist rate. "d" is the bullet diameter. "r" is the bullet length to diameter ratio (length of bullet divided by diameter). In .308, it works out fairly well. Sierra 168 grain Matchking is 0.308 inches in diameter. Bullet length is about 1.210 inches so we have a length to diameter ratio of 3.929. Plugging this value into the formula and using the 150 constant (the proven best velocity for the 168 grain MK is 2550 - 2600 fps), we get T=150 x (.308/3.929); T=150 x 0.078; T=11.76 inches or 11 3/4 inch twist …. One rotation of the bullet for every 11.76 inches of barrel traveled.."
http://www.snipercountry.com/hottips/TwistRate.htm
A faster twist rate like my Ruger M77 (1:10) really sings with heavy bullets.
It likes the 200gr Sierra Matchkings - It's a very very good bullet.
Zak Smith
Member
I have shot 125's to 210's in my 1:12 24" 308. They all shot sub-MOA.
If you are shooting 1000 yards, the 168gr SMK is not the best choice. Consider the 155 Lapua Scenar, the 175 Sierra MatchKing, or one of the Berger VLDs 168gr or heavier.
If you are shooting 1000 yards, the 168gr SMK is not the best choice. Consider the 155 Lapua Scenar, the 175 Sierra MatchKing, or one of the Berger VLDs 168gr or heavier.
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