PD260,
My understanding when you say "hard to seat" you mean it is hard push them deep enough so they are below the case head. Is this what you are talking about? Or are you saying it is hard to press them into the primer pocket opening due to a tight fit between the primer's outside diameter and primer pocket inside diameter?
If you are having a hard time seating them use a primer pocket uniformer to get the pockets deep enough for proper seating. I had an issue with several lots of different chamberings with Norma cases. You could encounter the same thing with Lapua brass.
I used a RCBS uniformer tool and had to make a cut then remove brass to remove material and repeat as much as three times. In addition to that the side of the uniformer was a tight fit. Had to use a tiny bit of water to lube sides of uniformer so it wasn't so difficult. All this was done with an electric power drill with uniformer chucked up and on a low speed.