bullet wieght vs barrel twist

lizard0017

lizard0017

New member
whats the deal with bullet weight vs twist of barrel, i guess what im asking is what bullet weight for certain twist rates, 1-8, 1-9, and 1-12, oh yeah its for 223, ive heard heavier bullets need less twist and lighter bullets need more twist is that true, and if it is, to what extint is it true /ubbthreads/images/graemlins/confused1.gif
 
Quote:
whats the deal with bullet weight vs twist of barrel, i guess what im asking is what bullet weight for certain twist rates, 1-8, 1-9, and 1-12, oh yeah its for 223, ive heard heavier bullets need less twist and lighter bullets need more twist is that true, and if it is, to what extint is it true /ubbthreads/images/graemlins/confused1.gif



It's the other way around - heaver bullets need faster twist, and a slower twist need lighter bullets.

Light bullets CAN be shot in a fast twist rifle, though not always to best results.


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ok so would it be to my advantage to get a fast twist or slow twist, my first deer was shot with an original Colt AR 15, at 70 yards with a iron sight when i was 13, so im used to just putting bullets in the dam thing and shooting, so as far as store bought ammo from 45 gr up what twist would be better, and FYI my dad has a FFL so he had one that was automatic, oh yes, it was fun, to bad im 27 now and hes not had it for about 10 years, it would through the lead.
 
Decide on how long(heavy) a bullet you will shoot and we can tell you what twist you need. Lighter(shorter) bullets should shoot fine.

Jack
 
"whats the deal with bullet weight vs twist of barrel"

It is actually the length not the weigh, but obviously weight will follow the length.

The mathematical formula, known as the Greenhills formula is:
T= 150 X D/R



Where: T is the twist required (number of inches for one revolution),
D is the bullet diameter (in inches)

R is the bullet length to diameter ratio, (length divided by diameter)

Conversely, to find out what length bullet will be stabilized in a given twist, use:



L = 150 x D x D
-----
T





(that is, 150 x D squared divided by T

where L= bullet length
The number 150 is a constant used by Greenhill and works well at velocities in the vicinity of 1500 fps or greater. At 2800 fps the constant can be changed to 180 with good results.

Note that it is bullet LENGTH, not weight that is important. Greenhill works well with all lead/lead-alloys commonly used for bullets
 
Quote:
If you use a 1 in 9 and you won't have to worry about the rest. It will stabilize heavy and light bullets



Yeah this is my advice as well. I have a 1x9 Stevens Savage that likes 45's al the way to 55's(Ihaven't tried anything heavier).

I also have a 1x8 AR barrell that has shot the 40's all the way to 60's just fine. I have shot 7 different weight of bullets and 5 different brands and they stabilized just fine.
 


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