Again with the twist rate

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RegForce

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Hi, I have two new precision rifles one being a Remington 700 sps .223 1 in 12 twist the other a Savage 10FP .308 1 in 10 Twist. I would like to know if anyone has thoughts on max bullet weight for either. The .223 ive been using 55gr with fair success but at 300m the drift is so much that i would like to go up in weight to limit this. I have heard and read numerous things. the 223 for example not to go past 55gr at all but on the other hand 62-65gr are fine. I was looking for clarification on this.
Thanx in advance
 
Best thing to do is buy a box and try them. The investment for 100 bullets (if you reload) to find if it will shoot them is negligible in comparison to knowing for certain whether they will or will not shoot.

Standard is though that 55 is max for the 1:12. Bullet weight has no bearing but the length of the bearing surface. That being said, a heavier bullet in one caliber will be longer since it cannot be wider.


As with 1:9 twist barrels, some will shoot 75grn bullets and some wont.
 
Don't be scared to go, to higher bullet weight. 1 in 14" twist in 223 will stabilise even 70gr semi-spitzer, acording to Speer reloading manual #9. Otherwise they wouldn't post data! In 1-12" twist in 223, regular 60gr spitzers should be no problem. Try to avoid 69gr VLD & BT though. Recent fad for tight twists, would you belive that you need 1-7" twist to stabilise 50 grainers! I shoot 50gr Barnes in my 1-14" twist 22 K-Hornet, and getting round holes at 200 yds.
 
Ok right on, so hopefully the 1 in 12 will be able to shoot a 62gr a-max or match point and if not o well. Now any thoughts on the 308?
 
First of all, twist rate determines how long a bullet can be stabilized. As a rule, the longer the bullet the heavier it is, so generally a 55gr. bullet is shorter than a 60, as well as lighter, so will stabilize in a slower twist. There are exceptions to this. Some of the lighter, but sleaker bullets are longer than the heavier, blunter bullets, and require more twist to stabilize them. Example. 64 gr. winchester powerpoint is heavier, but blunter than a 55 Sierra blitzking. I've had 1-14" barrels that would stabilize the 64 PP, but not the 55 Sierra. Same goes for the 70 Speer. Yeah, it's 70 gr., but it's a squat hunting bullet that is short and can be stabilized by a barrel that wouldn't do at all well w/ a 69 Sierra matchking, or 68 Hornady HPBT.
When it comes to optimizing downrange performcane out of a 1-12" .223, think 60 Vmax, or 50 vmax. If you want to knock over a bigger critters, try a 64 powerpoint, but don't expect to do it at 350 yards in a crosswind.

your 1-10" .308 will stabilize pretty much whatever you care to shoot out of it- that's lots of twist for .30 cal bullets.
 
RegForce said:
Ok right on, so hopefully the 1 in 12 will be able to shoot a 62gr a-max or match point and if not o well. Now any thoughts on the 308?
Click to expand...

How long is the 62gr Amax? Run Greenill, or tell me the length and I will, and you can have an idea if it's even worth trying.

(A 62gr Amax will be much longer than a 60-65 grain hunting bullet - see mpwolf's post for more info on why this matters).
 
Most twist rates are - in practice far far more than you need. If you can network with other people to try a sampling of different bullets, you will find that most rifles are capable of stabilizing a huge variety of bullet weights over short to medium distances. The hard and fast rules of what will and will not stabilize are few.

most non VLD 223 bullets are generally meant to feed from magazines and thus their weights in relation to their length are not necessarily contiguous. As Matt Says, it is length, not weight that determines twist requirement.
 
I've got a 1-14" .22-250 that does well w/ 60 gr. hornady sp's and hps, as well as the 64 winchester, but won't do the 60 vmax or 55 blitzking. A definate no go w/ 62 TSX.

Never seen or heard of a 62 amax...

For the price of a box of bullets you can try in your own barrel. Use those that don't work as trade bait to try others. You could probably get folks here to put 10 of whatever they have on the shelf into a padded envelope for the price of postage.
 
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