I'm aware of the diagram describing issues you may have with an AR platform rifle based on where your spent brass lands. So....here is what I'm seeing.
I've tried 3 brands of powder (CFE 223, Benchmark, & A2230-S Data). I'll focus on the 123 gr A-Max bullet for this example. Brass is brand new Lapua with a COAL of 2.250".
1. With all powders EXCEPT CFE 223, the brass lands about 10' out, in the 3:30 to 5:00 zone. The velocities are hitting around 2550 to 2600 FPS.
2. With CFE 223, the brass drops into a nice neat pile at about 1:00 to 1:30, some 8' away.
I'm seeing no indications of excessive pressure with the CFE 223 loads. The group, using 31.2 grains, is sub-MOA, @ 2600 FPS, with an SD of 10.0 FPS. I'm using a CCI 450 mag primer.
According to the diagram and my brass landing between noon and 3:00, I'm seeing an over gassed situation. I'm using an Alexander Arms 24" Overwatch upper.
According to Hodgdon's own burn rate chart, Benchmark is quite a bit faster than CFE 223. I've also used BL-C2, but didn't comment in my range notes where the brass was landing so won't include it in this discussion. I don't recall it being in the same landing spot as the CFE 223 brass but can't swear to it.
Anybody got an explanation as to why this is happening? This is not a one time thing....I see this every time I use CFE 223 in the Grendel.
I've tried 3 brands of powder (CFE 223, Benchmark, & A2230-S Data). I'll focus on the 123 gr A-Max bullet for this example. Brass is brand new Lapua with a COAL of 2.250".
1. With all powders EXCEPT CFE 223, the brass lands about 10' out, in the 3:30 to 5:00 zone. The velocities are hitting around 2550 to 2600 FPS.
2. With CFE 223, the brass drops into a nice neat pile at about 1:00 to 1:30, some 8' away.
I'm seeing no indications of excessive pressure with the CFE 223 loads. The group, using 31.2 grains, is sub-MOA, @ 2600 FPS, with an SD of 10.0 FPS. I'm using a CCI 450 mag primer.
According to the diagram and my brass landing between noon and 3:00, I'm seeing an over gassed situation. I'm using an Alexander Arms 24" Overwatch upper.
According to Hodgdon's own burn rate chart, Benchmark is quite a bit faster than CFE 223. I've also used BL-C2, but didn't comment in my range notes where the brass was landing so won't include it in this discussion. I don't recall it being in the same landing spot as the CFE 223 brass but can't swear to it.
Anybody got an explanation as to why this is happening? This is not a one time thing....I see this every time I use CFE 223 in the Grendel.
Comment