Favorite combo:
Ghost Rounds
Quad Barrel
Any Full-Auto trigger or the 5 Burst Trigger
Any Grip
Bullet Canister
Any stock
I got to level 401 before I got bored
dang bro your crazy good to get to 400 but I like
nukes
quadbarrel
5 burst (or full auto)
bounce grip if you can
low-key there's so many good ammo options it doesn't matter
reverse stock
you shoot 4x nukes behind you too and they bounce back forward cuz of bounce grip, (your things good too obviously you got to 400 but idk this is just what I like)