06-30-2020, 08:54 PM
(This post was last modified: 06-30-2020, 09:08 PM by Happy2Shoot.)
there are a lot of powders in the burn range to support 175gr. match bullets in the 308 Win i.e. M118LR.
as you can imagine capturing an ammunition component contract for the US military can result in large volume production, and prestige also.
another one of the newer powders in that burn rate range that i'm working with is IMR-4166 which is turning in some pretty low SDs, is supposed to be quite temp stable, and has a decoppering agent. RL-16 is supposed to have those features as well, but i haven't had the time, particularly now, to give that one a try yet. i'd like to try 4166 with some of the 130gr. bullets, but will have to wait until range time can resume.
if i recall the Navy contract for their 308 Sniper ammo featured IMR-4064.
if the Grendel had a scooch more case capacity i think it'd fall squarely in the middle of the powder burn rate that the 308 with heavy match bullets requires. as it is, varget, 4064, RL15 and RL16 etc. are on the slow side of the burn rate selection for the Grendel i think. maybe more usable with heavier bullets in the Grendel (130+) and for sure too slow for the 100gr. and less bullets for peak velocity. but if that's what you have on hand, many cases that's what gets used.
i saved this excerpt from a web search, but forgot to keep the source reference too, so i apologize for that : "The result, when it was standardized as the MK316 Mod 0 cartridge, was a Federal modified case (Drawing number 8347636), Federal match primer, Sierra 175 grain Matchking and 41.75 grains of IMR 4064 powder. According to the published sources this load will produce a muzzle velocity of 2640 fps out of a 24 inch barrel. The load as produced by Federal is claimed to produce under 1 MOA out to 1000 yards from an appropriate rifle. With the IMR powder the shift in velocity is only 20 fps from 0 to 100 Deg C, with the Standard deviation in velocity over 40 rounds being 15 fps or less."
anyway, these powders for the 308 Win with the heavier match bullets seem just a wee bit too slow for the Grendel with 123-130 gr. bullets to me, and definitely with bullets < 120gr. that is if you're after peak velocity. i'm sure if you decide you like varget with 90gr. TNT it will go bang. might be quite accurate, but you'll likely be giving up some fps to a more appropriate burn rate for that weight bullet.
-tdbru
as you can imagine capturing an ammunition component contract for the US military can result in large volume production, and prestige also.
another one of the newer powders in that burn rate range that i'm working with is IMR-4166 which is turning in some pretty low SDs, is supposed to be quite temp stable, and has a decoppering agent. RL-16 is supposed to have those features as well, but i haven't had the time, particularly now, to give that one a try yet. i'd like to try 4166 with some of the 130gr. bullets, but will have to wait until range time can resume.
if i recall the Navy contract for their 308 Sniper ammo featured IMR-4064.
if the Grendel had a scooch more case capacity i think it'd fall squarely in the middle of the powder burn rate that the 308 with heavy match bullets requires. as it is, varget, 4064, RL15 and RL16 etc. are on the slow side of the burn rate selection for the Grendel i think. maybe more usable with heavier bullets in the Grendel (130+) and for sure too slow for the 100gr. and less bullets for peak velocity. but if that's what you have on hand, many cases that's what gets used.
i saved this excerpt from a web search, but forgot to keep the source reference too, so i apologize for that : "The result, when it was standardized as the MK316 Mod 0 cartridge, was a Federal modified case (Drawing number 8347636), Federal match primer, Sierra 175 grain Matchking and 41.75 grains of IMR 4064 powder. According to the published sources this load will produce a muzzle velocity of 2640 fps out of a 24 inch barrel. The load as produced by Federal is claimed to produce under 1 MOA out to 1000 yards from an appropriate rifle. With the IMR powder the shift in velocity is only 20 fps from 0 to 100 Deg C, with the Standard deviation in velocity over 40 rounds being 15 fps or less."
anyway, these powders for the 308 Win with the heavier match bullets seem just a wee bit too slow for the Grendel with 123-130 gr. bullets to me, and definitely with bullets < 120gr. that is if you're after peak velocity. i'm sure if you decide you like varget with 90gr. TNT it will go bang. might be quite accurate, but you'll likely be giving up some fps to a more appropriate burn rate for that weight bullet.
-tdbru