01-27-2022, 09:50 AM
(This post was last modified: 01-27-2022, 09:59 AM by r.tenorio671.)
...finally got out to test the build and get some chrony data for Nosler 70gn Vgdon w/8208XBR. Only chronied the max charge weight I tested, the lower charges were primarily just to put rounds down the tube and adjust the gas block.
Pertinent build info: 18" BA w/RLGS, 1:7 twist, standard carbine buffer, tube & spring, SLR Sentry 7 AGB. No muzzle device used, thread protector only. Arken SH4 Gen2 4-16X50 on Arken 20MOA mount.
Testing ambient air temp 85F, 79% Humidity, 590 ft altitude, chrony measured at 15 ft forward of muzzle, chrony type=Chrony Beta Master.
Load info: Virgin Starline 6.5G converted to 6ARC, brass annealed before sizing in Hornady sizing die. CCI 400 primers, 30.0gns 8208XBR, Nosler 70VG FB seated at CBTO 1.6415", COAL 2.1215" (avg) . AVG VELOCITY = 3076 FPS
No pressure signs, no ejector smears, no extractor rim damage, primers very slight flattening but still have a little rounded edge.
Surprisingly, it was definitely well under a MOA grouping for all of the 5 charges tested and I wasn't shooting for groups, just needed a consistent aiming point so bullets would pass over the chrony sensors correctly. Due to getting out late, didn't get data on the 105 RDF's w/748...sunlight angle was low so 1st 2 rounds errored out so I stopped, will pick up next time. The main objective was to test build function and zero scope, both accomplished so I'm glad for that.
My data presented here is uniiqe to and safe in MY build, YMMV so work up your loads in a safe manner.
Pertinent build info: 18" BA w/RLGS, 1:7 twist, standard carbine buffer, tube & spring, SLR Sentry 7 AGB. No muzzle device used, thread protector only. Arken SH4 Gen2 4-16X50 on Arken 20MOA mount.
Testing ambient air temp 85F, 79% Humidity, 590 ft altitude, chrony measured at 15 ft forward of muzzle, chrony type=Chrony Beta Master.
Load info: Virgin Starline 6.5G converted to 6ARC, brass annealed before sizing in Hornady sizing die. CCI 400 primers, 30.0gns 8208XBR, Nosler 70VG FB seated at CBTO 1.6415", COAL 2.1215" (avg) . AVG VELOCITY = 3076 FPS
No pressure signs, no ejector smears, no extractor rim damage, primers very slight flattening but still have a little rounded edge.
Surprisingly, it was definitely well under a MOA grouping for all of the 5 charges tested and I wasn't shooting for groups, just needed a consistent aiming point so bullets would pass over the chrony sensors correctly. Due to getting out late, didn't get data on the 105 RDF's w/748...sunlight angle was low so 1st 2 rounds errored out so I stopped, will pick up next time. The main objective was to test build function and zero scope, both accomplished so I'm glad for that.
My data presented here is uniiqe to and safe in MY build, YMMV so work up your loads in a safe manner.