The only way I can think of to make it not as awful is to make it so it retains its charge level until you release M1.
You charge it up to 135, and it will always hit for 135 as long as your holding your fire button, and will reset to 45 when you let go. (if this is even possible)
Cuz right now it's entire ammo pool is outdone by a few shots from every other rifle.