What is the best method to match a bullet to a rifle twist? Using Miller's formula, Greenhill's formula, or just matching grain to twist?
- Thread starter CodenameFatBoy
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Matching wouldn't be a term I'd use. The only science involved is having enough twist to stabilize bullets of a maximum length. For cup and core bullets (lead core) that's defined using a weight range for a given twist with the recommended max weight for a given twist rate. The only way to match a bullet to a barrel is shoot it.
I've shot flat base bullets with an Sg of 1.1 at 1K yds. in competition. I set an accuracy record that stood for 7 or 8 years before it was broken. So there are general guidelines that we follow but not many absolutes. The target tells all.
I've shot flat base bullets with an Sg of 1.1 at 1K yds. in competition. I set an accuracy record that stood for 7 or 8 years before it was broken. So there are general guidelines that we follow but not many absolutes. The target tells all.
Thank you for your reply. I am completely new to precision shooting. I appreciate any information and corrections given. What would be the most efficient and practical way of finding what my rifle likes to shoot?
How precise do you want/need to be?
I pick a bullet that suits my needs (BC, weight, expansion if hunting, etc...) and almost always you can vary powder charges with a 0.010-0.025" jump to the rifling and can get sub 1/2 MOA with a "match" barrel in a bolt gun. Very rare exception that I have to change bullet brand/model to get it to shoot well.
You can burn up half a barrel's life trying every little variable out to see what's "best". I go for 1/2 MOA elevation spread @ 300 or 400yd and call it good.
I pick a bullet that suits my needs (BC, weight, expansion if hunting, etc...) and almost always you can vary powder charges with a 0.010-0.025" jump to the rifling and can get sub 1/2 MOA with a "match" barrel in a bolt gun. Very rare exception that I have to change bullet brand/model to get it to shoot well.
You can burn up half a barrel's life trying every little variable out to see what's "best". I go for 1/2 MOA elevation spread @ 300 or 400yd and call it good.
Just choosing a good bullet and crossing your fingers.
http://www.bergerbullets.com/twist-rate-calculator/
http://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi
Those calculators are a good tool to use to see stability, they arent the bible or rule of law but they are good baselines for initial insights. I usually go to hodgdons website http://www.hodgdonreloading.com/data/rifle to see what amounts of which powder would be used for a given weight bullet and then use the velocity from the low starting charge to see if it would be stable, if it isnt stable with the low end velocities its not something Im risking spending cash on to test myself.
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