I responded to a recoil spring question by rkramer and it set the gears to turning again on something I've been wondering about for a while. Will using the heavier recoil springs increase the velocity of the round? Since the Mak is a straight blow back gun going from a stock 17 lb. spring to the 21 lb. spring would mean a 4 lb. increase in spring pressure for the slide to overcome before starting to move. Would that not cause a rise in the chamber pressure and give a slightly higher bullet velocity? NB's the resident 9x18 expert and has done a lot of chrony work on mak rounds maybe we can talk him into running some test to see. I think I have a new unused set of Wolf springs I'd be willing to kick in for the testing. What do others think on this?