My old Winchester lever action of 1928 vintage has developed a problem; or maybe had it all along. So about one in 3 of my cast load (lee 170) won’t chamber fully; the lever won’t gonall the way home and put the rifle in battery. So I grabbed a very old box of federal 170 grain soft points and one of the 4 wouldn’t chamber fully. So I fished out some of my plinking unique loads and 1 in 3 wouldn’t chamber fully didn’t matter if I worked the lever smooth, slow, like I was trying to rip it off the frame; seems there is some type of obstruction as some the rounds that wouldn’t chamber have a dent in the boolit just above the case mouth. I can’t see any obvious thing wrong; and the action and barrel are inspection clean. Any thoughts?