Wanted to learn about what others are trying and share my experience so far:
Build:
Goal:
It would be fun to have a relatively light weight AR-15 platformed rifle that can consistently shoot at or under .5 MOA from 100 to 1000 yards.
Testing:
From prone using Joy-Pod bipod, Bigfoot rear bag and NF 5.5-22X50 optic. All rounds loaded to 2.26 COAL.
First steps:
Using the lathe, I modified some 6.5 Grendel dies by shaving off .040 from the base and replacing the neck sizing bushing. I set the dies up in a Forster Coax press and using annealed 6.5 Grendel brass, sized the necks down and pushed the shoulders back to the SAAMI specs. I also used a Sinclair carbide expander mandrel before loading.
First firing:
I was lazy, and using known data from the 6mm AR, I loaded 27.5 grains of H4895 under a 105 Berger Hybrid Target. This was way over pressure yielding speeds in the 2730 FPS range, heavy ejector swipes and unusably expanded primer pockets. Groups were all in the 1 to 1.5 MOA range at 100 yards. SDs were in the low single digits, however! Bad test - bad approach and dangerous. I know better and am lucky to re-learn that lesson without the pain that often accompanies such learnings.
Second firing:
Testing from 26.0 grains of H4895 up to 26.5 grains showed better results. The best results were the 26.5 grain charges with speeds of 2594 but SDs in the 17 FPS range. 100 yard groups were in the mid .5 MOA range. The groups got worse as the the powder charge decreased. No pressure signs, swipes or ejector marks at this charge range. It is, however, over pressure according to Quickload.
Changing gears:
I received some Hornady 105 grain Black factory ammunition that shot poorly in my barrel. Speed was good at 2640 FPS and SDs were a reasonable 11.4 FPS. Group sizes at 100 yards were terrible at 1.9 MOA.
I also tried some VARGET under the Hornady 108 ELD-M. 27 grains yielded 2554 FPS with a 5.5 SD and very repeatable .5 - .52 MOA at 100. I took these out to 700 and 900 yards on a windless day with the same .4 to .5 MOA results. The lack of wind is unusual but was welcomed. There were no pressure signs at this charge weight, however, Quickload estimates that this is 3900 PSI over SAAMI pressure.
Learning so far:
Fired by not resized converted 6.5 Grendel brass holds 34.74 grains of water and fired but not resized factory 6mm ARC cases holds 34.58 grains of water. In Quickload I edited a 6 PPC case for case length and case capacity and now get estimated MV within 2-4 FPS of what I have measured using the Labradar.
Disclaimer:
All of the above hand loads are above 52000 PSI, and, as such, I am obligated to warn everyone from trying them. If you do so, you are doing it at your own risk.
Next Steps:
It looks like the 27 grain VARGET and 108 ELD-M combo is very close to a predicted OBT node. .2 to .3 more grains is what I am going to test next.
Additionally, I don’t want to give up on H4895. I want to test this powder with both the 108 ELD-M and the 105 Hybrid Target.
Request:
There is already a big thread in progress discussing the merits of this cartridge which is interesting but not the intent of this one. Would like to keep this thread focused on practical experience and suggestions to optimize safe hand loads for this cartridge in semi-auto gas rifles.
Hope this helps someone,
Henryrifle
Build:
- 20” 1:7 twist 416 SS DMR Profile Ballistic Advantage barrel
- Vltor upper and lower
- Ballistic Advantage bolt in PSA premium bolt carrier
- Adjustable gas block
- TBAC Ultra-9 suppressor
- Geissele SSA-E trigger
Goal:
It would be fun to have a relatively light weight AR-15 platformed rifle that can consistently shoot at or under .5 MOA from 100 to 1000 yards.
Testing:
From prone using Joy-Pod bipod, Bigfoot rear bag and NF 5.5-22X50 optic. All rounds loaded to 2.26 COAL.
First steps:
Using the lathe, I modified some 6.5 Grendel dies by shaving off .040 from the base and replacing the neck sizing bushing. I set the dies up in a Forster Coax press and using annealed 6.5 Grendel brass, sized the necks down and pushed the shoulders back to the SAAMI specs. I also used a Sinclair carbide expander mandrel before loading.
First firing:
I was lazy, and using known data from the 6mm AR, I loaded 27.5 grains of H4895 under a 105 Berger Hybrid Target. This was way over pressure yielding speeds in the 2730 FPS range, heavy ejector swipes and unusably expanded primer pockets. Groups were all in the 1 to 1.5 MOA range at 100 yards. SDs were in the low single digits, however! Bad test - bad approach and dangerous. I know better and am lucky to re-learn that lesson without the pain that often accompanies such learnings.
Second firing:
Testing from 26.0 grains of H4895 up to 26.5 grains showed better results. The best results were the 26.5 grain charges with speeds of 2594 but SDs in the 17 FPS range. 100 yard groups were in the mid .5 MOA range. The groups got worse as the the powder charge decreased. No pressure signs, swipes or ejector marks at this charge range. It is, however, over pressure according to Quickload.
Changing gears:
I received some Hornady 105 grain Black factory ammunition that shot poorly in my barrel. Speed was good at 2640 FPS and SDs were a reasonable 11.4 FPS. Group sizes at 100 yards were terrible at 1.9 MOA.
I also tried some VARGET under the Hornady 108 ELD-M. 27 grains yielded 2554 FPS with a 5.5 SD and very repeatable .5 - .52 MOA at 100. I took these out to 700 and 900 yards on a windless day with the same .4 to .5 MOA results. The lack of wind is unusual but was welcomed. There were no pressure signs at this charge weight, however, Quickload estimates that this is 3900 PSI over SAAMI pressure.
Learning so far:
Fired by not resized converted 6.5 Grendel brass holds 34.74 grains of water and fired but not resized factory 6mm ARC cases holds 34.58 grains of water. In Quickload I edited a 6 PPC case for case length and case capacity and now get estimated MV within 2-4 FPS of what I have measured using the Labradar.
Disclaimer:
All of the above hand loads are above 52000 PSI, and, as such, I am obligated to warn everyone from trying them. If you do so, you are doing it at your own risk.
Next Steps:
It looks like the 27 grain VARGET and 108 ELD-M combo is very close to a predicted OBT node. .2 to .3 more grains is what I am going to test next.
Additionally, I don’t want to give up on H4895. I want to test this powder with both the 108 ELD-M and the 105 Hybrid Target.
- Will try 26.6 H4895 with 108 ELD-M expecting 2608 FPS out of my barrel.
- Will also try 26.5 H4895 with 105 Hybrid Target expecting 2635 FPS out of my barrel.
Request:
There is already a big thread in progress discussing the merits of this cartridge which is interesting but not the intent of this one. Would like to keep this thread focused on practical experience and suggestions to optimize safe hand loads for this cartridge in semi-auto gas rifles.
Hope this helps someone,
Henryrifle
