Oops, already posted above. Sorry.
So i will add a true story.
Was sitting about 60 yards away from the shooting benches, BSing with the guys.
Guy at benches fires a shot. Sounded strange. The 2nd shot , same hollow sound.
So i walk over to see what hes shooting. M94 30-30, a common round, as we all know. We talk.
Hes reloading his ammo with a 150 gr bullet. Normal. Then i ask what powder? He said IMR4350. As soon as he said it, i knew it, wrong powder.
I told him , wrong powder. He said " been loading it for years, not going to change now"
Yes, there are better powders.
HODGDON-
DOES MY SHORTER BARRELED RIFLE REQUIRE DIFFERENT RELOAD DATA?
https://www.hodgdonreloading.com/re...-barreled-rifle-require-different-reload-data
"
The chamber dimension determines the pressure. So, the pressure is the same when fired in that chamber in a rifle or a handgun. The barrel length has no impact on the chamber pressure and hence the reloading data (powder charge and pressure).
The length of the barrel will change the actual velocity you observe. In general as the barrel gets shorter than standard the velocity will lower, and as the barrel gets longer than standard the velocity will increase. This does not change the reload data (powder charge and pressure), just the velocity."