Author Topic: Formula for best bullet weight ? (Read 666 times)

Doe · « **on:** January 21, 2006, 02:06:44 AM »

Now I know there's a FORMULA for optimum bullet weight for a given rifle twist. ANYBODY?

cattleskinner · « **Reply #1 on:** January 21, 2006, 07:01:57 AM »

Doe,

Here's one site that I found that might be worthwhile to check out. If that doesn't do it for you, do a Google search for "Greenhill formula". Have a good'un

.

http://www.loadammo.com/Topics/July01.htm

~~~Amos

mountainview · « **Reply #2 on:** January 21, 2006, 08:36:47 AM »

Doe, not trying to be facetious but there are a lot of variables that go into determining the best bullet weight for ones gun. The rules of thumb are good starting points but the best way (and most fun) to determine the "best" bullet weight is testing by shooting at the bench.

Don Fischer · « **Reply #3 on:** January 21, 2006, 10:43:10 AM »

What mountainview say's is very true. But I have also found that certain cartridges, indeed certain barrels like different bullet's. My 308 like's the mid range bullets best, 165gr and 180gr. Won't shoot 150gr well for some reason. My 25-06 likes the heavier end, 6.5-06 mid range. Generally I've found mid range to work best unless it's a magnum.

I had a 7mm Rem Mag that thrived on 160 gr bullets but didn't shoot 140, 145, 150 class or 175gr bullets other than acceptable. Then it shot 115 gr bullet's like they were made for it.

A 7X57 didn't shoot anything real well everything around 1 1/2" untill I tried 154 gr round nose bullet's. 1" group the norm but it wouldn't shoot 154 gr spire point's. Go figure, that's what makes this so interesting!

Slamfire · « **Reply #4 on:** January 21, 2006, 04:19:26 PM »

I think one would be better off choosing the optimum bullet for the game he hunts, then selectin' the twist to best suit the bullet.

killdeer · « **Reply #5 on:** January 23, 2006, 04:10:26 AM »

Doe,
it's mostly bullet length.
If your contemplating a rifle purchase, I can see how shooting at the bench wouldn't be practical.
Rifling twist rates can and do vary from manufacturer to manufacturer, and even from model to model.
Generally speaking, faster twist rates are used to stabilise heavier (IE longer) bullets.
If you have a specific example of what you are trying to decide, I am sure someone here can help. :-)

PA-Joe · « **Reply #6 on:** January 23, 2006, 04:55:09 AM »

It also has a lot to do with the twist rate of your barrel. 223s for example come with twist rates of 1/14 1/12 1/9 and 1/7. 1/14 like <50 grain points and 1/7 >68 grain points.