08-20-2012, 05:59 PM
Azprc Wrote:Most of the grendel reamers are set for the 123 or the hunting bullet ogives, which means that the 108 has a longer jump to the rifling. This reamer sets the jump to .020 with a 2.295 coal, which also puts the base of the bullet at the shoulder instead of down in the powder column. This barrel has never shot a bad group, yet. Sub 1/2 moa at 300 yards and this target in the video is a hair over 1 moa and the misses were on me. Shot broke at bullet impact, which is the shooters fault.
There is only one Grendel reamer standard, and it has a compound throat angle, that is meant to handle a wide range of bullets. The .264 LBC reamers aren't standardized, so there is no industry pattern for that reamer, but my understanding is that it was first built around the 123gr SMK, then the 123gr AMAX.
When I have a custom barrel built for me, I have at least one bullet in mind that I think I know I'll be shooting, and the smith cuts the chamber based on that, which is what Azprc did here, with great results demonstrated on-target from a 20" pipe at over 1k, which is impressive for the Grendel.
The nose profile/ogive of the 108 Scenar is more of a VLD-type pill, which increases its BC for its weight, making it a great bullet for a case such as the Grendel, where powder capacity is limited. 8900 density altitude helps out a lot, compared to sea level, since there isn't much atmospheric pressure to resist bullet flight up there.
What mags did you use to get 2.295" COAL? I plan on using the PRI's.