Test for barrel choke by pushing a tight fitting ball down the bore. If it runs with even pressure all the way thru, or gets slightly tighter at the muzzle, you are in luck. If the ball suddenly pushes easily as you get to the muzzle, cut that section off.
It's easy to make a mark on the rod where the loose spot begins, then pull the rod out, lay it on the bbl to mark the bbl.
One should always check their barrels before making ANY cuts, before inletting. Sometimes there is a tear in the rifling or terrible loose spot. If you discover this soon after you purchase it, you can return for a refund or exchange. If you've inlet bbl, and cut tenons, or shortened the bbl, or a bunch of time goes by before you discover the bad spot, it's MUCH harder to make good on it.