Thanks, What does the 2860 BAR mean? Thanks. Also, there is discussion on using reduced modern powder loads with less pressure and velocity. Opinion?
2850 BAR is about 44,000psi. That's the pressure the proof house says is safe. That being said, I would be leery of a black powder gun being proofed to a nitro powder load of a full nitro express. Think of it as being three guns we're talking about here:
Gun 1 - A .577 BPE (Black Powder Express)
Gun 2 - A .577 Nitro for Black powder
Gun 3 - A .577 Nitro Express
Gun 1 might only weigh 9lbs. It was meant to handle black powder pressures and velocities.
Gun 2 might weigh 9lbs, or maybe 10lbs. It was made for blackpowder, OR nitrocellulous powder (cordite) of EQUAL PRESSURE AND VELOCITY.
Gun 3 might weight 13-14lbs to endure the full force recoil of the significantly more powerful Nitro Express loading. That includes heavier bullets, more powerful powders, much heavier barrels and stock.
The loading of a blackpowder gun with equal pressure and velocity in an nitro-for-black load is possible, but there are hazards. Using the wrong powder can create barrel damage due to too much space in the case, or powder shifting, or many other reasons. It requires expert research and due care to make sure the loads built are correct for the BPE or Nitro-for-Black application. At any rate, the gun won't regulate correctly if you don't have similar speeds and pressure because the sights and barrel wedge were regulated for say 1600fps with a 500 grain bullet, yet the full nitro load is calling for a much heavier charge and a heavier bullet at higher velocities. Beyond safety, that just isn't going to work for regulation.
Be careful. Research heavily. Do not use a .577NE load in a gun designed for .577 black powder express.