Either. You can remove metal from the bolt face, you can remove metal from the breach face of the barrel, or you can opt for shorter links. Removing the metal and keeping the breach face or bolt face square will require some skill with tools and yes, the cartridge guide lug at the bottom of the bolt face can be problematic. That is why I suggested you contact Pioneer Gunworks for custom links, once you know what the head space is ..... or isn't.
If you elect to DIY, be very careful. Especially if you elect to pull the barrel. If you warp the receiver, you'll have a very expensive 3 dimensional wall decoration, suitable for framing