Thank you both for your idea's on this. I think my next step will be to put one cartridge in and try to verify if it's hanging up on the front or the rear. I'll then add a second cartridge and see how the alignment of the top cartridge changes.

I didn't see any 220 grain ammo commercially available - just 180 grain Winchester and Remington. Hornady didn't have any 220 grain listed currently. I did, on deeper search, find two providers (Black Dog and Ventura Heritage) I'm unfamiliar with that offer 220 grain at premium prices.

If I become convinced that the problem is overall length, I'll probably 'live with it' as I don't plan on doing anything other than range shooting with this rifle. If it looks like it's a mechanical problem, I'll be more inclined to try to solve it.

Again, thank you both for your thoughts.