Echo 1 M4 TC (Tactical Carbine)

I just bought this and I don't like the accuracy. My friend was standing about 75 feet away and the BB's hit everything but him. So I wanted to buy a suppressor and then a new inner barrel. I found what I wanted (Matrix inner barrel), but couldn't decide on length. The two that was undecided on were a 470mm tightbore (110mm Suppressor) and a 510mm tightbore (190mm Suppressor).The 190mm Suppressor is $10 more, and the inner barrels are the same, so is it worth $10 to get the extra 40mm? Thanks.

its all really preference, id go with the longest inner barrel possible then accomidate that with the right silencer.