Re: .284 win?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sandwarrior</div><div class="ubbcode-body">Well, I've tested it from +103 deg to -18 deg. And I say it's not.
It's about the only Alliant powder that is not temp sensitive. What were their loads/cartridges? </div></div>
Would love to hear details on this. Care to elaborate?</div></div>
Because of how it's made.
First understand burn speed is determined by size of kernel/ball/flake. The smaller the faster the burn. Bigger=slower burn. Pressure is determined by formulation. How much of this gets added, less of that, etc.
RE-17 is the first, and only (so far as I know, others probably exist), powder to have the burn retardant formulated to be mixed integrally with it while making the kernels. As most (all) double based powders are more temp sensitive because the nitro-glycerin added (which makes it a double base) slow down their burn in the winter. However, just because it's a single base doesn't mean it's naturally less temp sensitive. IMR powders remain uncoated, except for 4064. That and the Hodgdon Extreme powders have the burn retardant sprayed on after the kernels are formed. If you will notice the H-Extreme powders now have much smaller kernels. What Hodgdon did was reduce the size of the kernels and decrease the burn speed by upping the burn retardant.
A burn retardant works chemically by snuffing the burn. If it gets too hot, or too much pressure, free radicals spin off and the burn slows. Doing this can also extend the burn length down the barrel.
Anyhow, because of the retardant being mixed into the powder instead of on it, it gives better control. A reminder though that in order for the powder to be at peak performance retardant still needs to be limited. So, when you get charges too high it uses up the chemical capacity of the retardant. Once that happens, any coated/mixed powder is going to act just like it was uncoated. You get big bad pressure signs.
As far as temperature testing it, I've tested it here in Minnesota in the .22-250, .243, 6mm Rem, .257 Rob, .257 Wby, 6.5x55, .270 Win, 7mm-08, 7x57, 7WSM, .280AI, .308, 7.5x55, 30-06, 300 WSM and .300 WM. In +90 down to -10. Extreme cases being +103 down to -18 (I have tested powders up here in -26 but not RE-17). The results, I've found are that it generally takes a little bit less of it than H4530X in comparable loadings. But, remains right around +/- 50fps in those temps. It favors the smaller cases but works very well with the appropriate bullet weights in '06 capacity cases. One caveat to that was MontanaMarine was getting excellent results in his 30-06 with it, pushing 208 A-max's (?). I can't say where he was at in the pressure curve with it. It won't show overloads until quite a ways over where it is supposed to operate.
Does that help?