Several things here. First, size a case properly. That does not mean size it all you can. Back off your sizing die about half a turn or better. Size the case and try it in the chamber. If it is tight, turn the die down a little. Try this until it goes with no effort. If this cannot happen, check the brass length. Trim length should be .010 under max. If it is not too long and it still will not chamber easily, even with the die set as far down as it will go, then you will probably need to try another sizer die. Sometimes one will not do enough with a particularly tight chamber.
Once that is done, use then longest bullet you have with a fairly blunt ogive. The amax is better than the vld, but use something even longer, if possible. If you still can not get rifling marks on the bullet, the lead must be either way too long, or burnt out. I can't imagine Pac-Nor making a chamber that long, that makes me think it is eroded so far it needs to be set back and re-chambered.
One other thing, make sure the expander ball is not pulling the shoulder of the case out upon sizing. If it sticks in the neck, it can do that. I once had trouble with a 243 that stuck badly and ruined several pieces of brass because I had not lubed the necks. I have found that simply using a plastic bore brush (not a bronze one, that makes it worse) in a drill does a good job cleaning the necks and make the expander ball pull through the neck easily. On the occasion that it is still a bit tough, I put a little lube on the brush and use it that way.
Try these things and let us know what you find. I am always curious with these things, and I like to learn.
