The Firing Line Forums - View Single Post

Bart B. · February 5, 2013, 03:12 PM

IMR4064's gonna meter within a 3/10ths grain spread in most measures using proper and consistant techniques. It does in my old Redding and RCBS ones. That's good enough for excellent accuracy through 600 yards as proved by Federal's Gold Medal Match .308 Win. ammo shooting well under 1 MOA at 600 yards.

As IMR4064 has less fps change per 1/10th grain charge weight change than others (IMR4895, for example), it seems to do well with a 3/10ths grain spread in the 40 to 50 grain charge range.

There's lots of evidence out there that metered charges of stick powder to a 3/10ths grain spread gives better accuracy than exact or 1/10th grain spreads of ball power charges. I've seen that myself. And Lake City ammo plant caught all sorts of flak when they changed their 7.62 match ammo's powder to a Winchester ball powder with less than half the charge weight spread as IMR4895 had previously. That ball powder charged stuff was often called "9 ring ammo" as that's the smallest scoring ring top shooters could count on for their fired shots to fall inside of.

February 5, 2013, 03:12 PM	#3
Bart B. Senior Member Join Date: February 15, 2009 Posts: 8,927	IMR4064's gonna meter within a 3/10ths grain spread in most measures using proper and consistant techniques. It does in my old Redding and RCBS ones. That's good enough for excellent accuracy through 600 yards as proved by Federal's Gold Medal Match .308 Win. ammo shooting well under 1 MOA at 600 yards. As IMR4064 has less fps change per 1/10th grain charge weight change than others (IMR4895, for example), it seems to do well with a 3/10ths grain spread in the 40 to 50 grain charge range. There's lots of evidence out there that metered charges of stick powder to a 3/10ths grain spread gives better accuracy than exact or 1/10th grain spreads of ball power charges. I've seen that myself. And Lake City ammo plant caught all sorts of flak when they changed their 7.62 match ammo's powder to a Winchester ball powder with less than half the charge weight spread as IMR4895 had previously. That ball powder charged stuff was often called "9 ring ammo" as that's the smallest scoring ring top shooters could count on for their fired shots to fall inside of. Last edited by Bart B.; February 5, 2013 at 03:20 PM.