Twist rates for various calibers?

[mark5pt56]

http://www.riflebarrels.com/products...wist_rates.htm

[Positive Displacement]

Is the bullet key holing past 300 yards or oval hits? This will tell you if the bullet is being spun to slow.

If the bullet is spun to slow you will see key holing. To fast and the bullet will spin across the lands, shearing the bullet. To fast and you will see larger amounts of copper deposits in the barrel and larger groups down range. In your case you are not spinning the bullet to fast.

Due to air density the 223 has a very poor BC to begin with. Sorry, but the 223 was not designed to be a long range caliber. The environment exhibits a lot of havoc on the bullet once it leaves the barrel due to the 223 aerodynamic qualities.

Can longer ranges be achieved with the 223? Yes, but it will be more susceptible to the environment making it much more difficult to accurately hit.

The ideal range for the 223 is around the 300 - 400 yard mark. The 1:12 twist is fine for the caliber You can go to a faster twist to get to longer ranges but the 223 just does not have the BC to play at longer ranges consistently.

If you want to play out past 500 yards, accurately, I would say go to a larger caliber with a better BC.

I agree with the above, I would love to be able to go 600 yds. It's not key holed at 300 yds. Seems that with the investment though I could just step up to a .308. I really appreciate the response, I think my decision is made to just keep it stock.

[geo351]

Looking thru the info here i see nothing on the 300 win I have a 20in 1in 11 twist i shoot Premium 185 grain to 400 in a silver dollar grouping. on another site a guy out of texas recommends a 208 to 210 grain to reach out and drop my moa, any suggestion would be appreciated, leupold 9-32 with 50 mm optics.

[68shooter]

I'd stick with 69's and quit worrying about it. You get better velocity and I can't tell much of a difference in drift when shooting steel. Good luck finding bullets, powder or ammo. I bought it all and buried it in my back yard.

[BruceLeroy]

There some interesting new theories out there on twist rates. Todd Hodnett thinks we should/can twist faster for the heavier bullets. I tend to agree. I just ordered a 1/8 twist barrel for my .308 for some heavy rounds. Will be an interesting test to say the least.

Be bold, order a barrel and see what it does.

[markm]

I just ordered a 1/8 twist barrel for my .308 for some heavy rounds. Will be an interesting test to say the least.

How heavy?

Good grief... A 1/11 will stabilize any reasonable length bullet for .308.

[Alpha Sierra]

Due to air density the 223 has a very poor BC to begin with. Sorry, but the 223 was not designed to be a long range caliber. The environment exhibits a lot of havoc on the bullet once it leaves the barrel due to the 223 aerodynamic qualities.

Can longer ranges be achieved with the 223? Yes, but it will be more susceptible to the environment making it much more difficult to accurately hit.

The ideal range for the 223 is around the 300 - 400 yard mark. The 1:12 twist is fine for the caliber You can go to a faster twist to get to longer ranges but the 223 just does not have the BC to play at longer ranges consistently.

If you want to play out past 500 yards, accurately, I would say go to a larger caliber with a better BC.

This is complete nonsense.

Air density has absolutely nothing to do with the ballistic coefficient of a bullet.

Also, bullets of equal BC behave aerodynamically EXACTLY the same when they are launched at the same speed.

There are plenty of .224" match bullets in weights between 75 and 90 grains that have BCs between .435 and .480 that will absolutely run with any .308 at any distance.

This is no theory. I have plenty of personal experience sending .224" bullets into the 10 and X ring at 600 yards out of 20" ARs with 1/8 and 1/7 twists.

[CRT2]

Savage 12FTR (Target Rifle Series) has a 1:7 twist rate. http://savagearms.com/firearms/models/

[DocGKR]

I have become a firm believer of faster twist rates, especially on shorter barrels. 1/8 is a good rate for 16" .308's.

[Alpha Sierra]

It's a question of simple math why shorter barrels benefit from a faster twist rate to maintain stability despite their lower muzzle velocities.

A bullet needs a certain rotational velocity to remain stable thoughtout its flight.

I'm going to extremely oversimplify the physics because I am going to assume the bullet reaches full MV essentially as it leaves the cartridge.

In that case, the bullet's rotational velocity in revolutions/second is simply the product of the rifling rate (expressed in revolutions/inch) and muzzle velocity (in inches/second).