Shorten and re-thread Rem. 870 shotgun barrel... good idea?

[rockland]

MD yes I do like a SxS shotgun if it has a straight stock and I owned a Winchester 20" cylinder bore pump for many years but same drawback with most short barrel or sawn-offs... no choke.
For me the cylinder was fine on hares and possums out to 25 yards but anything beyond that was hit n miss. Same using buckshot vs. pigs and goats. A half or modified choke gets me out to 40 yd.
So I want to keep the interchokes if I shorten the barrel.

If I weren't left handed I'd just get the Benelli M2 21" and be happy