i read somewhere that elmer keith (?) had experimented with 50 bmg brass that was modified to have a tube from the primer pocket to the top of the powder charge. I believe this was done in an effort to increase velocity. I'm not sure how it would accomplish this with standard loads. I do wonder if benefit's might be realized as far as barrel life, or even layering differnet burn rate powders in an effort to maximize velocity (flattened pressure curve). I think these might be accomplished by the thought (mind you not theory) that the powder would burn from the front of the case to the rear instead of being blown out into the barrel.

I realize that this would be very labor intensive to develop brass with said tube, hotter primers would be required to ignite the powder, it might be very hard on brass, the space required for the tube might negate any theoritcal gains, etc. but i wondered if it wouldn't allow for much hotter loads due to flattening (not lowering) the pressure curve. in other words, keeping the peak pressure for longer periods of time as the bullet passes down the barrel.