I think you might just remove the factory spacer, mill a bit off it and replace it again. You may also have to "adjust" the bolt baffle to allow the bolt the additional rearward motion to cleanly pick up the longer cartridges. I just went through this on mine with 80gr Bergers and found that despite the "Wylde" chambering, I was limited to an OAL limit of 2.390" before the bullet would remain jammed in the throat when extracting an unfired cartridge. At least in my case with the 80gr it is the chamber that imposes the limit and not the magazine.

So before you run off and tweak the magazine, get your barrel installed and verify what the chamber will allow you to do.....