Maximum pressure should not be that hard to keep within limits with a powder like Longshot. The problem with those loads I am told is that the pressure curve is elongated, meaning that the pressure down the bore is higher than other loads. So if load one produces 8K psi with pressure dropping to 2K by 9" and load two produces only 7.5K psi with pressure dropping to 4K at 9" you get in effect a 100% increase of pressure at 9". Pressure and distance are for example purposes, only so you get the point.
We have been told repeatedly that the pressure drops rapidly away from the chamber but what if it does not? Or not fast enough? You want to shoot a gun with marginal barrels that are .020 or so thick? I would not. Just another case of buyer beware.
