no-lead bullet?

[moooose102]

i just had a thought, that i do not know the answer to. a no-lead bullet, like barnes's x-bullet, or any other one for that matter, is going to be longer for the same weight than a jacketed lead bullet will be. will that extra length require a different twist rate than a standard bullet? i like to use fairly heavy bullets, so a solid alloy bullet would be pretty long compared to a standard bullet. (22-243-25-30-45 calibers) i kind of get the twist rate to bullet weight thing for standard bullets, i was just wondering if the same holds true for alloy bullets or not with their extra length? or if the twist rate is strictly designated to weight rather than length.

 

[Jim Watson]

Twist rate is dependent on length, not weight. Assuming bullets of the same caliber and weight, a boattail spitzer needs a faster twist than a roundnose; a copper bullet needs a faster twist than lead core, the tin core Varmint Grenades are long for weight and need faster twist than lead core.

 

[moooose102]

thanks Jim.

 

[sneedb82]

I didn't think that was necessarily true considering a 55gr .223 will require a 1/12 twist (originally), but can be used in a 1/7, 1/8, 1/9 twists whether it's a lead or solid metal bullet. Have I been misinformed (this is just one particular bullet example, as I own a 1/12 twist .223). They are different sizes now due to the metal vs. lead argument.

 

[moooose102]

imo, the 22 cal is by far the most finicky in the twist rate problem. from what i understand, it is ok to go with a faster twist rate (unless it gets so fast it litterally spins the bullet apart) but not a slower. when i tried shooting hornady 75 grainers out of my handi-rifle (1 in 12) they were keyholling all over the place. i have gone as light as 40 grains, with no problems. actually, until i had the keyhole problem, i did not even know about the twist rate variances. of course, i was never all that much into guns until the last 4 or 5 years. i have been shooting for over 40 years, but it was just casually, for fun. nowdays, i take a much more deliberate, applied approach to it. i have probably shot more in the last 5 years than i have in all of the rest of my life combined. that by no means makes me an expert about any of this. but i am learning, and want to continue to.

 

[Jim Watson]

sneed,

It is true that you can use a bullet in a faster twist than necessary.

The 12" twist was adopted by the military to stabilize a 55 grain boattail FMJ in cold dense air. For many years the standard .22 centerfire twist had been 14" because nobody wanted to shoot anything heavier or longer than a 55 grain flatbase varmint bullet or 52 grain boattail target bullet. When the army and service rifle target shooters got in the act, twists got faster and faster to shoot heavier (longer) bullets at longer ranges. I have a 6.5 twist barrel made to shoot 90 grain VLDs, for example.