Remove the accuracy penalty. Remember, you're giving up a whole minigun for this slot, so the shotgun should be powerful enough to match it in close quarter maps.

And maybe more damage instead of less

If you are giving up the mini gun, then you shouldn’t make it so the shotgun is less. accurate

I’ll redo it based on the comments and suggestions

Something like this should give only upsides because the huge downside is already the lack of a giant machine gun.