Two piece bases = 2 holes per base. I bought a lot of Mausers that had been drilled and tapped for one piece bases. So, only one hole in the rear bridge and that hole isn't in the right spot for an off the shelf rear base. I used a lot of Leupolds because they have narrower hole spacing. Or, made or modified existing bases to work. And of course, added that second hole to the bridge.
