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Old October 2, 2012, 06:37 AM   #16
Bart B.
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Join Date: February 15, 2009
Posts: 4,435
Regarding metering of powders, I've metered a lot of Varget and IMR4895 (almost the same as H4895) and a small amount of RL15. Varget had the smallest spread in weight, IMR4895 was a close second and RL15 was a close third. They all would meter to no worse than a 3/10th spread in charge weight.

Some folks believe that best accuracy happens only with powder charges having the smallest spread in weight, they're either ignoring or not aware of the fact that benchresters meter all their powders for ranges up to 300 yards ('tis a waste of time to weigh each charge for ranges up to 400 yards if you use the right powder for your bullets in .308 cases). With the right powder and charge weight, accuracy of 5/8 MOA at 600 yards is easily attainable with metered charges dumping weight spreads as much as 3/10ths grain. Federal's Gold Medal .308 Win. match ammo is made that way and it performs as such in well built rifles. Military match ammo loaded on high speed metering of IMR4895 powder under Sierra's match bullets shoots that well or better in good bolt guns; at 100 yards no worse than 1/3 MOA.

For bullets 160 to 190 grains in the .308 Win. IMR4064 and one of the VV powders (I now forget, but it's got close to the same burn rate as 4064, maybe N140 or N540??) has the best track records for accuracy, but they don't meter too accurate from measures. You've got to weigh them to no worse than a 2/10ths grain spread.

Here's a link to a power burn rate table, one of the extruded ones between H4895 and IMR4064 is the best for .308 Win. use:

http://www.reloadbench.com/burn.html

Last edited by Bart B.; October 2, 2012 at 06:44 AM.
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