There are so many different directions you could go with your current platform.

You could just swap in another 5.56 barrel, maybe a different twist or length or gas system.

You could change caliber, just use a 300 blackout barrel and muzzle device and everything else stays the same except the 300 BLK ammo.

Or you could add a 6.5 grendel barrel with muzzle device and swap out your bolt with a 6.5 bolt and now you looking at hitting targets from 600-1200 yards.

There are many things you could do....

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M&P15 sport II, Retired Army