Originally Posted by
darkker
Unfortunately primers aren't reliable reporters at all. If you look at my recent post of pressure testing in the Creedmoor I have pictures of the same load shot with small rifle primers and large. All the pressures were recorded with a strain gauge pressure system, you'll see the rifle was running essentially identical pressures; but the primers were radically different. Even if you stick with all Idendical, when we pressure tested in the 308 a few years ago, the primers don't show "signs" until well beyond 70,000 psi. I'm not saying they are worthless, but don't use them for what they are not.
The point I after with the data(which I wasn't concise with), was that powder isn't a fixed thing. Looking at the referenced Nosler data against the online Hodgy data, even though the charges vary substantially, the velocities are very similar. Powder lots do vary by quite a large margin at times. Neither source will tell you what the lot numbers tested were, when the data was tested. Without being able to measure pressures accurately, the better route to go(if you want to stay within SAAMI pressure limits) is to focus on the chrono. If you start low and work up, then how fast you are relative to book speeds, at a given charge weight; will give you an idea of how your burning rate compares to what was tested. Mass produced rifles, even with magical aftermarket barrels, have looser tollerances than SAAMI min spec test fixtures, so will always be slightly slower at the same pressure. If you exceed book velocity, you exceeded book pressure.
The last I knew, yes, the Dogtowns were being produced by Nosler. They have had different mfgrs over time, but believe them to currently be from Nosler.
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