Wouldn't that also push the shoulder back by pushing the brass further into the die?
I would be sure you do some measuring before you do too many or fire them. Don't just rely on the case gauge, you can't see where the shoulder sits inside there, they'll fit as long as it's short enough.
I would buy another shell holder to use after you've fired them once as well. You don't want/need to be pushing things around that much once they're fire formed.
Sounds like a small base die (if available) would be a better solution.
I would check if they'll chamber without modifying the shell holder, let the chamber smooth out the bump at the base when you fire them (if they'll chamber).
To anyone buying brass.
After reloading for semi autos for a number of years now I've learned that they're very hard on your brass so spending big bucks on Lapua is just not cost effective, the difference in group sizes from cheap brass to Lapua is only fractions of an inch (if you do everything else perfectly), you don't gain enough for the cost when you're ruining it in half the loadings (or less) a bolt gun would get. Plus you're way more likely to lose those shiny $2 things with a semi.
Good luck