I have suffered long and hard from barrel burn out. The remorse lingers longer than one would think.
In as much as barrel life decreases with the number of bullets down the bore the idea would be to minimize the number of shots not shot at game, if its a hunting rig. If its a competition rig you do what's. necessary to win with little or no regard for barrel life.
I have to form each case used in the rig. Cases last maybe 6 firings. I avoid down loading a 270 Allen Mag to 270 WSM performance. Why have a Lamborghini with a Briggs & Stratton engine?
The best option, though most expensive, would be to have some one, or even yourself in another dummy barreled action chambered with the same reamed used on your chamber.
The more practical approach would be to do initial fire forming without passing bullets down the bore. Using a fast powder such as Unique and cream of wheat or corn meal on top of the filler, to the base of the neck. A single square, or less, of TP (unused of course) to plug the neck.
Be careful with the powder and charge! Very high pressures are achievable!
Note also that the barrel can become too heated. Pacing forming shots is prudent.e
This method will result in a "nearly" fully fire formed case. The shoulder may not be 'perfectly' formed but is ready for a full tilt load for sight-in, load development and drop chart development and hunting.
I have found, as have others, that when the smith does his job properly, there is very little or no difference (acceptable for me and i'm particular) in performance between the first post fire form load and subsequent shots.
