Originally Posted by Supertrucker
I shoot 7STW and 280 Ackley. RL 22 shoots with both accuracy and speed, but I have read that the "H" extreme powders are better for long range accuracy because they are more temperment to temp changes. H1000 shoots awesome in my 7STW, but is at least 100 fps slower than the RL22. H4831sc shoots great in my 280AI, but is also slower in velocity. If both the RL22 and the H powders shoot for the same accuracy, would I be better off to forget about the 100 or so fps loss?
Velocity is related to pressure. so if one load is faster then pressure is higher and burn rate is
probably faster with the same powder charge.
Also primers can effect the way different powders react.
Most powders show little velocity change at lower temps (O to 50 degrees) but from 50 to 100
degrees they change a great deal. where they get bad is from 80 to 120 degrees.
This is where the extream powders make a difference .
Some of my loads will change velocity as much as 150 ft/sec using ball powder and non extream
powders over a temp range of 20 to 100 degrees F . one of my pet loads for the 7/08 uses
H414 (ball powder) and will go from 3010 ft/sec @ 30 degrees to 3158 @ 100 degrees.
The same pressure load with Varget only changes 18 ft/sec over this range of temperatures
so I don't have to worry about keeping my amo warm or cool.
Some rifles prefer other powders and I end up dealing with them but only if I can't make
the extream powders work.
J E CUSTOM