Consider building a "ramp" to the front of the magazine.
If you check out some of the Mauser conversions to .308 (or 7.62X51), they reduced the length of the mag follower and installed a "ramp" so the nose of the bullet does not free float too long. Go the full depth of the magazine.
"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
Life Member NRA
Life Member NAHC