AR Comp

[Chucker]

Hey guys,

There seems to be very little data out there on this powder so I'm throwing up my initial results. I've never used this powder before. Observations: I was very surprised how well it metered considering it is a coarse stick type powder (at least compared to TAC which I am more familiar with). For me it metered just as well as TAC. It seems you can get higher velocities out of this powder for a given charge with less pressure. I was using case deformation and primer flattening to determine the pressure observation but I know that's not scientific nor absolute. Also, I was using Wolf's harder 5.56 primers so that may have something to do with it. Samples sizes are small but the SD's were very low from my experience. Other details:

62 gr FMJ

Mixed brass

Wolf 5.56 primers

2.25" OAL

Lee Factory crimp

64 F, 53% RH, partly cloudy

23.0 gr AR Comp, out of 16" bbl:

2826 2869 2845 2842 2849 2831 2810

23.7 gr AR Comp, 16" bbl:

2904 2935 2941 2926 2923 2902 2923 2909 2924 2888

24.4 gr AR Comp, 16" bbl: *

3011 3031 3026 2995 3019 3012 3047 3009 3002 3017

* - I got one flattened primer and a slight bulge at the bottom of my first case (3011 fps reading). I almost decided not to continue but I fired another one and didn't get any bulging or flattening and the rest were the same. Regardless, due to the high velocities and the fact I did see one case with pressure signs, I would probably NOT select 24.4 gr as a go to load.

I am not an accuracy guy and I load for bulk practice but the 23.0 gr load gave me the 'best' accuracy out of the three loadings out of my rifle (AR type, 16" midlength). It was interesting to me to see the resulting velocities from such relatively light charges. For reference, I would have to throw 25+ grains of TAC to get around 2800 fps out of the same barrel. This may be a common phenomina for those more experienced but it was interesting to me.

[Steve RA]

I think if you would not use mixed brass the results would be much better. Different brands - especially mil brass - has quite a difference in case capacity which makes a lot of deviation in velocities, pressure and accuracy.

If nothing else, sort by brand and use all the same in batches.

[Chucker]

I think if you would not use mixed brass the results would be much better.

Ha! Shows you how much I know. I actually thought the standard deviations looked great!