Thread: 6.5x55 SE Sanity Check

Originally Posted by Magnetite

I finally found a place to do some testing.

I've only tested the 2209 so far. I stopped at 45.5gr which was doing 2842fps from a 580mm barrel with suppressor. This matches up with the ADI max load and .260 Rem speeds. If anyone's interested here's the results (4 shots each charge):

Grains fps SD ES
42.5 2693 23.3 52
43.0 2726 12.6 28
43.5 2750 10.4 19 (only 3 shots)
44.0 2761 16.8 39
44.5 2780 9.9 24
45.0 2805 9.5 22
45.5 2842 21.8 43

~43.3gr and ~44.8gr will be worth looking at. I'm not sure if it's worthwhile testing lower loads. I didn't get any pressure signs but it seems like testing higher loads would be asking for trouble. Thanks everyone's suggestions.

Greetings Magnetite,
Looks like your rifle gives a little more velocity than mine with your selection of components. I note that you are using a suppressor which some suggest gives more velocity so perhaps this is part of it. Low standard deviation and extreme spread don't always result in greater accuracy so testing for accuracy is probably the next step. To me 45 grains and 45.5 grains looks like a good place to start. Your velocity is in line with the .260 Rem so your pressures should be a little lower. John Barsness suggested that the 6.5 x 55 needs about 2 grains more powder to equal the .260 Rem velocity at about the same pressure (probably a little less) so I think you are in safe country with either 45.0 or 45.5 grains of AR2209. I wouldn't bother with the lighter loads. Both the 129 grain Hornady Interlock and SST are pretty soft projectiles so don't run the pressures up as much as some of the harder projectiles, especially the Barnes.
Regards Grandpamac.