I am new to the Grendel so I am trying to develop an accurate load for my new Grendel built.
I ve had a 6.8 SPC for a few years now so I already had some Hodgdon Benchmark and IMR8208XBR and I decided to try these ones first.
Load and range data:
Powders:
IMR8208XBR from 27 to 29 gr in 0.5 increments
Benchmark from 27 to 27.5 gr
Cases: are Hornady new, resized, trimmed to 1.513 inch
Primer: CCI41
Bullet: Hornady A-max 123 gr.
COAL: 2.302 inch.
Crimp: light crimp with the Lee factory crimp.
Velocities: (see chart for details)
XBR: from 2443 to 2617 fps
Benchmark: from 2501 to 2544 fps
Temperature: 88F
Altitude: 800ft
Caldwell Chronograph at 10 feet away
5 rounds of each load
Barrel: 6.5 Grendel II 24 inch 5R, rifle length gas, no muzzle device installed.
Notes:
These are loaded long, but they feed nicely both in my PRI and ASC magazines (I am using 6.8 SPC mags hat I had already)
I made a home-made distance to lands COAL guage to see how much jump I will have with this COAL and I measured 2.356 inch COAL when the bullet touches the lands giving me about 0.05 inch jump to lands.
The result of the long COAL was that up to 28.5 gr I could hear powder rattling in the case, but not at 29 gr which means that at this COAL about 28.5 grains is the case 100% capacity for this bullet.
As expected Benchmark was very accurate, but it's probably too fast for this round. XBR did well, but didn't impress me.
image.jpeg
Distance to lands COAL guage
image.png
Summary of hand loads. On the chart I listed the two loads, velocities and std, group size. Red means too hot, don't try.
image.jpeg
Best group target
I was surprised and impressed how much faster the factory A-max load was in my Rifle: I registered 2648 fps 10 shot average with 36 std 1.25 inch at 200 yards. I would love to replicate this round!
Now this is the first time I shoot this brand new barrel, so this was my breakin. Results might change in the future.r
I know 28.5 gr XBR is the favorite load of many here on this forum. Is there a powder that can do better that I should try? I was thinking A2520, Hodgdon Varget or LVR?
Here are my requirements:
I need a powder that is slow enough but not too slow for a 24 inch barrel that is safe enough to fill 100% the case for COAL 2.302 inch, probably 29 gr extruded or 29.5 ball that is stable in the temperature range I shoot: 25F to 100F. Do you guys have any suggestions?
I ve had a 6.8 SPC for a few years now so I already had some Hodgdon Benchmark and IMR8208XBR and I decided to try these ones first.
Load and range data:
Powders:
IMR8208XBR from 27 to 29 gr in 0.5 increments
Benchmark from 27 to 27.5 gr
Cases: are Hornady new, resized, trimmed to 1.513 inch
Primer: CCI41
Bullet: Hornady A-max 123 gr.
COAL: 2.302 inch.
Crimp: light crimp with the Lee factory crimp.
Velocities: (see chart for details)
XBR: from 2443 to 2617 fps
Benchmark: from 2501 to 2544 fps
Temperature: 88F
Altitude: 800ft
Caldwell Chronograph at 10 feet away
5 rounds of each load
Barrel: 6.5 Grendel II 24 inch 5R, rifle length gas, no muzzle device installed.
Notes:
These are loaded long, but they feed nicely both in my PRI and ASC magazines (I am using 6.8 SPC mags hat I had already)
I made a home-made distance to lands COAL guage to see how much jump I will have with this COAL and I measured 2.356 inch COAL when the bullet touches the lands giving me about 0.05 inch jump to lands.
The result of the long COAL was that up to 28.5 gr I could hear powder rattling in the case, but not at 29 gr which means that at this COAL about 28.5 grains is the case 100% capacity for this bullet.
As expected Benchmark was very accurate, but it's probably too fast for this round. XBR did well, but didn't impress me.
image.jpeg
Distance to lands COAL guage
image.png
Summary of hand loads. On the chart I listed the two loads, velocities and std, group size. Red means too hot, don't try.
image.jpeg
Best group target
I was surprised and impressed how much faster the factory A-max load was in my Rifle: I registered 2648 fps 10 shot average with 36 std 1.25 inch at 200 yards. I would love to replicate this round!
Now this is the first time I shoot this brand new barrel, so this was my breakin. Results might change in the future.r
I know 28.5 gr XBR is the favorite load of many here on this forum. Is there a powder that can do better that I should try? I was thinking A2520, Hodgdon Varget or LVR?
Here are my requirements:
I need a powder that is slow enough but not too slow for a 24 inch barrel that is safe enough to fill 100% the case for COAL 2.302 inch, probably 29 gr extruded or 29.5 ball that is stable in the temperature range I shoot: 25F to 100F. Do you guys have any suggestions?
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