05-12-2018, 08:43 PM
Welcom Msalm. So you would basically consider your 22 LBC to have a "standard" 22 LBC chamber / throat / leade? I am seriously contemplating ordering one from BHW in a 1:10 twist if they will do the 1:10 twist
I have a 20" BHW 556 barrel that was supposed to be 1:8 but its actually 1:9. Really had me ticked off at first since it won't shoot 77s for a damn, but it is shooting 55 grain NBTVs at 3150 lights out to 450 and as far as I can tell thus far, its holding to 550 (I have to go by 10" plate swing at 550 and they all seem center enough). Anyways, that's giving me 252k RPM for the thin jacketed varmint bullet and a quick and dirty calculation gives me the exact same 252k if they were 3500 out of a 1:10.
A 1:10 twist obviously limits the barrel to light bullets and my concern is that the bullets don't have too much jump and/or sit too high in the case given how relatively short the Grendel case is. I'm seating them at 2.255 in 223. I don't know what the jump is, but I did finally pick up a replacement modified case yesterday so I can check. It looks like seating the 55 gr NBTV with the bottom of the bearing surface at the bottom of the neck puts them at about 2.050 in a Grendel case. They look similar to the 53 gr VMAX. What are you seating those at and what's your jump? I'm pretty sure BHW uses PTG reamers (they do state in their FAQ that they use PTG Go and No Go Gauges) but I could always confirm that. Thanks!
I have a 20" BHW 556 barrel that was supposed to be 1:8 but its actually 1:9. Really had me ticked off at first since it won't shoot 77s for a damn, but it is shooting 55 grain NBTVs at 3150 lights out to 450 and as far as I can tell thus far, its holding to 550 (I have to go by 10" plate swing at 550 and they all seem center enough). Anyways, that's giving me 252k RPM for the thin jacketed varmint bullet and a quick and dirty calculation gives me the exact same 252k if they were 3500 out of a 1:10.
A 1:10 twist obviously limits the barrel to light bullets and my concern is that the bullets don't have too much jump and/or sit too high in the case given how relatively short the Grendel case is. I'm seating them at 2.255 in 223. I don't know what the jump is, but I did finally pick up a replacement modified case yesterday so I can check. It looks like seating the 55 gr NBTV with the bottom of the bearing surface at the bottom of the neck puts them at about 2.050 in a Grendel case. They look similar to the 53 gr VMAX. What are you seating those at and what's your jump? I'm pretty sure BHW uses PTG reamers (they do state in their FAQ that they use PTG Go and No Go Gauges) but I could always confirm that. Thanks!
Let's go Brandon!