Last weekend I tried Win 748. Same results, the powder was slower than predicted by QL (I think Win 748 and BL-C(2) are closely related if not the same powder with different names).
I plan to adjust the powder burn rate in QL to match the measured velocity, which my guess is will be below 40 kpsi. The heaviest load was filled to 105% of available case capacity, so time to move on to the next powder. Next, I think I am going to try H322. I am working my way up from slower powders to faster powders so I end up with the lowest pressure load that meets my performance goal.
I haven't mentioned this yet, but the first set of loads I made to scope the rifle in used RL-10X. I cooked up some loads with QL that had the case capacity filled to a little over 100%, but when I actually loaded the loads I could hear powder shaking around inside when I shook the case. This means that either the grain size or void volume assumed by QL was off.
When I took the rounds out to the range, they were slower than predicted. Normally I would adjust the burn rate in QL to match the batch of powder I have, then use the adjusted numbers to predict the pressure I was at. From there I adjust to get back up or down to my pressure goal with that particular batch. That cannot be done with this batch of RL-10 though, because both the geometry and burn rate are are variable
-JR
Last edited by JR_Maley; 07/22/10.
