My foray into Grendel, parts and notes as follows:
Mega Machine ambi receiver set
Proof Research 20" CF barrel
SLR 15" Ion UL HG
2A Ti gas block
LT MBT trigger
AA Bolt, Toolcraft carrier
BCM receiver extension
BCG Mod 3 grip
Carbine Buffer, 1 tungsten/2 steel weights, 3.8oz, (H1 weight)
Std carbine buffer spring
V7 Ti pins and lw fwd Asst
B5 SOPMOD stock (not pictured)
Geisele CH
Seekins ambi safety and oversized BHO
Bushnell 4.5-18x44 LRHSi
Badger Ordnance 20MOA, 1.4" mount
GA Recce 7 silencer (not pictured)
Build notes: The upper receiver was true and required no additional work; barrel has interference fit to receiver and set in loctite adhesive. Gas block was too close to HG so MLOK slot was relieved to eliminate contact. The gas block and HG contact caused initial accuracy issues which went away after material removal. The .850 GB and 1.30" ID HG are very close.
MBT trigger is heavier than I prefer, I like it's feel but I will probably change it out for an AR Gold trigger. It's a shame since the $99 MBT sale started this entire build.
Extractor gouged brass rims, I broke the corners but it still needs a bit more work. Ejector spring trimmed. The added Tungsten buffer weight is a little too much for initial load work up but probably perfect with the silencer. I am working on load dev and haven't shot it with the silencer yet. I didn't measure the gas port but it is perfect; brass piles up at 1 o'clock, -1' with H1 vs carbine buffers.
Initial Load Dev:
DA 3331, 55 deg, RH 35, 6mph
6.5gr Hornady Custom SST Factory
Avg 2458
ES 35.8
SD 13.85
DA 4030, 67deg, RH 21, 11mph
6.5gr Hornady Custom SST Factory
Avg 2464
ES 56.19
SD 22.44
123gr ELD-M 1.666" comp (touching inside mag)
H4895
27.4gr
Avg 2412
ES 33.56
SD 12.24
27.6
Avg 2430
ES 19.53
SD 8.48
27.8
Avg 2440 (3 shot group)
ERRor
28.0C
Avg 2465
ES 27.57
SD 10.67
IMR 8208XBR
27.4
Avg 2379
ES 20.09
SD 9.21
27.6
Avg 2407
ES 27.7
SD 10.44
27.8
Avg 2436
ES 32.20
SD 12.8
28.0
Avg 2444
ES 27.51
SD 11.53
Load dev notes: H4895 looks good on paper and has very consistent performance, however, it is bulky and I ran into pressure as soon as the charge became compressed. I want to love this powder but it is inappropriate for the 123gr ELD-M bullet. 8208 builds velocity even slower than H4895, both show pressure at 28.2 grains. The initial ladder for both had dented shoulders low in the work up. Accuracy for both powders was mediocre at best...moving on.
I did a single shot ladder of LeverEvolution from 29.2gr to 31.4C. The top of the ladder was 2574fps and just starting to show pressure (swipes). Half MOA nodes present. This powder is very fine and royal PITA in my throwers, I want to hate it but it looks like a performer.
Mega Machine ambi receiver set
Proof Research 20" CF barrel
SLR 15" Ion UL HG
2A Ti gas block
LT MBT trigger
AA Bolt, Toolcraft carrier
BCM receiver extension
BCG Mod 3 grip
Carbine Buffer, 1 tungsten/2 steel weights, 3.8oz, (H1 weight)
Std carbine buffer spring
V7 Ti pins and lw fwd Asst
B5 SOPMOD stock (not pictured)
Geisele CH
Seekins ambi safety and oversized BHO
Bushnell 4.5-18x44 LRHSi
Badger Ordnance 20MOA, 1.4" mount
GA Recce 7 silencer (not pictured)
Build notes: The upper receiver was true and required no additional work; barrel has interference fit to receiver and set in loctite adhesive. Gas block was too close to HG so MLOK slot was relieved to eliminate contact. The gas block and HG contact caused initial accuracy issues which went away after material removal. The .850 GB and 1.30" ID HG are very close.
MBT trigger is heavier than I prefer, I like it's feel but I will probably change it out for an AR Gold trigger. It's a shame since the $99 MBT sale started this entire build.
Extractor gouged brass rims, I broke the corners but it still needs a bit more work. Ejector spring trimmed. The added Tungsten buffer weight is a little too much for initial load work up but probably perfect with the silencer. I am working on load dev and haven't shot it with the silencer yet. I didn't measure the gas port but it is perfect; brass piles up at 1 o'clock, -1' with H1 vs carbine buffers.
Initial Load Dev:
DA 3331, 55 deg, RH 35, 6mph
6.5gr Hornady Custom SST Factory
Avg 2458
ES 35.8
SD 13.85
DA 4030, 67deg, RH 21, 11mph
6.5gr Hornady Custom SST Factory
Avg 2464
ES 56.19
SD 22.44
123gr ELD-M 1.666" comp (touching inside mag)
H4895
27.4gr
Avg 2412
ES 33.56
SD 12.24
27.6
Avg 2430
ES 19.53
SD 8.48
27.8
Avg 2440 (3 shot group)
ERRor
28.0C
Avg 2465
ES 27.57
SD 10.67
IMR 8208XBR
27.4
Avg 2379
ES 20.09
SD 9.21
27.6
Avg 2407
ES 27.7
SD 10.44
27.8
Avg 2436
ES 32.20
SD 12.8
28.0
Avg 2444
ES 27.51
SD 11.53
Load dev notes: H4895 looks good on paper and has very consistent performance, however, it is bulky and I ran into pressure as soon as the charge became compressed. I want to love this powder but it is inappropriate for the 123gr ELD-M bullet. 8208 builds velocity even slower than H4895, both show pressure at 28.2 grains. The initial ladder for both had dented shoulders low in the work up. Accuracy for both powders was mediocre at best...moving on.
I did a single shot ladder of LeverEvolution from 29.2gr to 31.4C. The top of the ladder was 2574fps and just starting to show pressure (swipes). Half MOA nodes present. This powder is very fine and royal PITA in my throwers, I want to hate it but it looks like a performer.
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