Jay Christopherson
Not An Admin
Just thought I would drop a line about the testing I have been doing with 8208 XBR and my 6 Dasher. This was all done with CCI 450 primers and 107SMK's.
The long and short of it is that I was able to achieve excellent accuracy (some in the 1's at 200 yards), but was not able to achieve the velocity that I was looking for.
I tested from 30.6 grains all the way up to 32.1 at which point I began to see visible signs of pressure in terms of flattened primers and "sticky" bolt lift.
I did find a nice accuracy node at 31.8 grains, but my velocity at that load was only around 2937 fps avg. I would guess that there is an OBT at that charge weight (big fan of OBT), but it's hard to confirm without real data in QL. If I go by my adjusted Accurate 2460 (see below), 31.8 grains puts me nearly dead on an OBT node.
Here's the actual data I collected. I shot these round robin style, 5 shots at each weight:
LOAD AVG. V. GROUP(MOA)
30.6gr: 2846 fps .109
30.9gr: 2869 fps .651
31.2gr: 2892 fps .338
31.5gr: 2915 fps .345
31.8gr: 2937 fps .155
32.1gr: 2960 fps .290
My rifle has a Barnard Model P action, 29" Broughton 5C in 1:8. I did record E.S. and S.D. for these as well. I can post if you like, but they were very small so I felt like I had clean loads.
While accuracy was pretty good, at least on a par with my normal RL-15 loads @ 34.1gr, velocity was about 55 fps down from what I get with RL-15. I get more velocity with less pressure (subjectively) with RL-15. The XBR did burned quite a bit cleaner though IMO. Much less powder fouling at the end, after 30 shots compared to what I am used to seeing with RL-15. I expect that I will go back to RL-15 for now. I have an order of 108BIB's coming in that I am going to test next and I may break out the XBR for a couple of tests with those. I can trade a little velocity for accuracy if it ends up significantly better.
One last note was that I was able to get a good matchup in QL with Accurate 2460 by adjusting the Ba to .4789 (opposed to Accurate's normal listing of .4880). I ONLY used this to predict velocities- I don't trust any of the other numbers (pressure, etc..), they being two entirely different powders. YMMV.
The long and short of it is that I was able to achieve excellent accuracy (some in the 1's at 200 yards), but was not able to achieve the velocity that I was looking for.
I tested from 30.6 grains all the way up to 32.1 at which point I began to see visible signs of pressure in terms of flattened primers and "sticky" bolt lift.
I did find a nice accuracy node at 31.8 grains, but my velocity at that load was only around 2937 fps avg. I would guess that there is an OBT at that charge weight (big fan of OBT), but it's hard to confirm without real data in QL. If I go by my adjusted Accurate 2460 (see below), 31.8 grains puts me nearly dead on an OBT node.
Here's the actual data I collected. I shot these round robin style, 5 shots at each weight:
LOAD AVG. V. GROUP(MOA)
30.6gr: 2846 fps .109
30.9gr: 2869 fps .651
31.2gr: 2892 fps .338
31.5gr: 2915 fps .345
31.8gr: 2937 fps .155
32.1gr: 2960 fps .290
My rifle has a Barnard Model P action, 29" Broughton 5C in 1:8. I did record E.S. and S.D. for these as well. I can post if you like, but they were very small so I felt like I had clean loads.
While accuracy was pretty good, at least on a par with my normal RL-15 loads @ 34.1gr, velocity was about 55 fps down from what I get with RL-15. I get more velocity with less pressure (subjectively) with RL-15. The XBR did burned quite a bit cleaner though IMO. Much less powder fouling at the end, after 30 shots compared to what I am used to seeing with RL-15. I expect that I will go back to RL-15 for now. I have an order of 108BIB's coming in that I am going to test next and I may break out the XBR for a couple of tests with those. I can trade a little velocity for accuracy if it ends up significantly better.
One last note was that I was able to get a good matchup in QL with Accurate 2460 by adjusting the Ba to .4789 (opposed to Accurate's normal listing of .4880). I ONLY used this to predict velocities- I don't trust any of the other numbers (pressure, etc..), they being two entirely different powders. YMMV.
