Yes - however there are limits as in velocity loss - to below the effective range.
For example, shooting 70gr. or 75gr. of 2F powder with an 80gr. measure of shot, will normally shoot better patterns than with equal measure full of shot and powder, that many people use.
Something else you can do to drop muzzle pressures is switching out the 2F for 3F - as in dropping the charge to 60gr. to 65gr. 3F. This can improve patterns over the 2F loads due to the lower muzzle pressure, yet the velocities will still be about the same and sufficient to kill the game - depending on range and what the game is and shot size used.
Something else than can be done - was tried and found worked in the 1880's with non-choked ctg. guns, was running a thread tap in the muzzle and down a 1/2" or more to rough it up to help hold or retain the wads somewhat. The cuts need not be deep.
With early breech loaders, the "thread's" would work for only a few shots then would fill with fouling and stop working to retard the wads. This was reported by W.W. Greener in "The Gun and it's Development" 9th edition.
For us to use this method in a ML, the "threads" would be kept quite clean just by loading from the muzzle - hence should work for every shot. As well, I cannot see this being detrimental to round ball shooting, at all.
