Re: Which DBM require no fitting?
The HS Precision DBM is a drop-in for the Remington 700P & LTR with HS Precision stock.
It's generally considered inferior to the systems that use AICS magazines, but they're not drop-in.
I don't know if they do it anymore, but years ago GA Precision would inlet your stock for the Badger M5 / AICS magazines for a nominal fee and had a great price on the Badger M5 bottom-metal.