Bullets with shorter bearing surfaces don’t result in as much friction against the bore, so they don’t build as much pressure.
No, there is no powder combination which could be safe in a short barrel but unsafe in a long barrel. The pressure peak happens very early in the bullet travel, that’s basic internal ballistics.
Custom barrels, for multiple reasons, can often yield higher velocities than rough and irregular hammer forged factory barrels. Whether it’s lower friction from bore smoothness (hand lapped), or greater consistency in bore diameter, or something as simple as how 5R type rifling engages the bullet, it’s a very common happenstance.
No, you do not need “high temp” primers for slow burning powders. Magnum primers are nice for spherical powders like Leverevolution, but not necessarily required, and it has absolutely nothing to do with the burn rate, but rather the form factor of the powder.
You’re missing a LOT of basic reloading knowledge to be making such unfounded presumptions.
Last edited by Nomercy448; 04-17-2018 at 08:39 PM.