I need some advice on my Remington 870 . It came with a rifled slug barrel but I'm getting poor groups at 75 yds . I'm looking at sending it to Tar-Hunt to have it worked on . The cost is a bit steep (around $ 500.00) I have also looked at Hastings barrels , but don't know alott about them . Does anyone have any advice ?? I would like to shoot 1 to 2'' groups at 100 yds