I have a 1924 Ithaca Flues 16ga. Only after firing the gun is hard to breech. Top lever is to the right on lockup. No slack or wiggle when open or closed. Opens simply by moving top lever to the right when unfired. Floating firing pins but don't seam to be sticking. Cocking plunger (as i have seen in pics) hump is now flat. i am not sure wheather or not if this could be the problem or it lies elsewhere. Any help?