This is a drop-in part for Remington 700 Hunter stock. Shooters can use detachable magazines with this part installed. It takes AICS pattern short action magazine. The part comes with one Magpul PMAG 5 7.62 AC
https://www.magpul.com/products/bolt-action-magazine-well-%E2%80%93-hunter-700-stock
Price: $69.95
PMAG 5 7.62 AC takes 5 rounds, but follwer can be modified for one more round. Price is $34.95
https://www.magpul.com/products/pmag-5-762-ac
From: Magpul