03-19-2020, 02:54 AM
Lawrence97,
I've been shooting AR15s & bolt rifles chambered for 6RAT for several years, although I don't recall shooting at 100yds for group with any of the heavier bullets. All but one of my bbls were 24" long (the exception being a Bartlein 28" on a match rifle upper), and most liked Berger 105VLDs better than S107MKs. Just reviewed chrono data, and even in the 28" bbl, best velocities/best accuracy were with H4895 at 2750fps. I ran as much as 30.1grs of RL15, but that gave obvious pressure signs, at an avg vel of 2840fps. I used this upper in XC Hi Power matches, so max range was 600yds, and this is the distance I normally tested all my heavy bullet loads at. Since 600yd stage is slow prone, all the heavy bullet loads for this upper were seated w/o regard for mag length limitations, and single loaded with a SLED.
I have had good shooting with S95MKs (not the poly-tipped version), seated to mag length, mostly out of a 24" Krieger 1-8tw bbl I contoured & chambered for a series of practical/tactical matches, where all ammunition was mag fed. RL15 & Wolf SRM primers gave VG accuracy at just under 2750fps; I've seen these bullets perform pretty well with other powders, but believe RL15 gave best accuracy. Downside is that RL15 is temp sensitive. Even in a Howa Mini bolt rifle with a 24" Bartlein, I'm not getting significantly higher velocities, although this little rifle has shot consistently better groups at 600yds than any of the several AR15 6RATs I've built & shot. As you're probably aware, the RAT has the body blown forward about .700", and with reduced body taper & 40* shoulder, probably has from 3.5 to 4grs more case capacity than your 6 Grendel, so this is hardly an apples-to-apples comparison. Just wanted to toss this out there to perhaps mitigate your apparent disappointment with lower velocities than expected, if that indeed is the case.
I've been shooting AR15s & bolt rifles chambered for 6RAT for several years, although I don't recall shooting at 100yds for group with any of the heavier bullets. All but one of my bbls were 24" long (the exception being a Bartlein 28" on a match rifle upper), and most liked Berger 105VLDs better than S107MKs. Just reviewed chrono data, and even in the 28" bbl, best velocities/best accuracy were with H4895 at 2750fps. I ran as much as 30.1grs of RL15, but that gave obvious pressure signs, at an avg vel of 2840fps. I used this upper in XC Hi Power matches, so max range was 600yds, and this is the distance I normally tested all my heavy bullet loads at. Since 600yd stage is slow prone, all the heavy bullet loads for this upper were seated w/o regard for mag length limitations, and single loaded with a SLED.
I have had good shooting with S95MKs (not the poly-tipped version), seated to mag length, mostly out of a 24" Krieger 1-8tw bbl I contoured & chambered for a series of practical/tactical matches, where all ammunition was mag fed. RL15 & Wolf SRM primers gave VG accuracy at just under 2750fps; I've seen these bullets perform pretty well with other powders, but believe RL15 gave best accuracy. Downside is that RL15 is temp sensitive. Even in a Howa Mini bolt rifle with a 24" Bartlein, I'm not getting significantly higher velocities, although this little rifle has shot consistently better groups at 600yds than any of the several AR15 6RATs I've built & shot. As you're probably aware, the RAT has the body blown forward about .700", and with reduced body taper & 40* shoulder, probably has from 3.5 to 4grs more case capacity than your 6 Grendel, so this is hardly an apples-to-apples comparison. Just wanted to toss this out there to perhaps mitigate your apparent disappointment with lower velocities than expected, if that indeed is the case.