Having trouble sizing 10 gauge hulls

[Cory Rams]

I tapped hull number 2 into my barrel. I had to trim it approx an 1/8” or so to get it to flush. I figured since I trimmed the other to approx 2 3/4” I would make them all the same length and trimmed number two down to equal length of the first shell. After tapping and removing shell number 2 from the barrel several times it still had to pushed in with force and tapped out. I ended up running it through my sizer several times, sanding with 320 grit sandpaper on the high spots and polishing. Kept rotating all the steps for a good hour or so till till shell number two would drop into either chambers loosely. What was weird is the first shell I sized yesterday grew to the point it chambered with force again. I repeated the process till both shells dropped into both chambers with a loose fit. Good thing I only have four shells total or I would have quit while I was behind. Two more to go. I plan on pin tumbling them when I’m done sizing them. I’m hoping tumbling will smooth out the surface and aid in chambering.