Gtscotty
Member
- Joined
- Jul 2, 2007
- Messages
- 3,635
I recently finished a 6.5 Grendel AR build, and did a quick OCW-ish load development to get a useable hunting load before the end of antelope season.
I found a load that will work for this year, but along the way have run into some split groups where I'll basically have two fairly tight groups of 3+2 that have me scratching my head.
Here are pics of the workup:
I suppose that the vertical split groups could just be from a load between nodes, but it does seem odd to me that they tend to stack into two distinct groups instead of a string like I'm used to seeing.
In the past with bolt guns, I've traced split groups to:
-bedding
-gusty winds
-trigger control problems with light rifles
None of these seem to apply in this case. There was some wind, but not terrible, no bedding on an AR, the trigger is pretty good, and with my can mounted the AR is ~8lbs.
A few causes I've considered:
-CTR stock has some movement and isn't great off of bags, could be causing instability issues (kind of like a bedding problem).
-round, thin handguard torquing on the bags under recoil.
-maybe the split groups are just an illusion from the small sample size.
-bullet/powder combo isn't right for the rifle.
-crappy shooting.
Any input from the resident AR experts? Have you seen split groups with ARs before, any guesses at the cause?
I found a load that will work for this year, but along the way have run into some split groups where I'll basically have two fairly tight groups of 3+2 that have me scratching my head.
Here are pics of the workup:
I suppose that the vertical split groups could just be from a load between nodes, but it does seem odd to me that they tend to stack into two distinct groups instead of a string like I'm used to seeing.
In the past with bolt guns, I've traced split groups to:
-bedding
-gusty winds
-trigger control problems with light rifles
None of these seem to apply in this case. There was some wind, but not terrible, no bedding on an AR, the trigger is pretty good, and with my can mounted the AR is ~8lbs.
A few causes I've considered:
-CTR stock has some movement and isn't great off of bags, could be causing instability issues (kind of like a bedding problem).
-round, thin handguard torquing on the bags under recoil.
-maybe the split groups are just an illusion from the small sample size.
-bullet/powder combo isn't right for the rifle.
-crappy shooting.
Any input from the resident AR experts? Have you seen split groups with ARs before, any guesses at the cause?