Bolt Action shottys have a lot going for them IMO. The down side seem to be that the bolt adds to the length making them pretty long. I reckon a short barrel would make them handier. Balistically shottys only need about 20 inches if I recall correctly.
Its a long ass gun thats for sure, reason i didn’t chop the barrel was for velocity, thinking a longer barrel may lend itself to long distance, maybe all the powers burnt by the time it gets up there i’m not to sure now you mention it, i was eyeing off a short version in a local shop but missed out 
In my limited experience you get more range out of a longer barrel, my 16 & 20 inch shoties spit huge fire balls, which is all just wasted velocity.
That is not always true. In the case of slow burning powder a longer barrel will provide more velocity because it needs that length to fully expend all of the energy during combustion. However if it’s a fast burning powder, and most shotgun powders are, then all of the energy is developed in a shorter time. Therefore a shorter barrel will achieve close to Max velocity. After max velocity is achieved then friction will start slowing down the payload,
That’s true mate, shotgun powders are generally fast but some are slower than others.
I still see massive fireballs spit from my shorter barrels and if its still burning its still expanding. That says to me that I’m wasting energy and possible velocity, but I might be wrong as I have not tested any loads with a chrony.
Its observable in the field though I reckon, I can drop bunnies at greater distances with my Winchester 37A than I can with the 16in Russian doorbell. I know pattern size will be a factor too, will have to test it at plinkfest if Brett brings his chrony down.
There are a lot of variables. To me the question is,
4-6" off a bolt action shotgun significantly reduce its range?
I don’t think it would be a hell of a lot.
Oh, don’t forget the balls are pretty inefficient projectiles, so they slow down pretty fast no matter what speed they start at. E.g. the faster they start the faster they slow down. Or you quickly lose most of the velocity advantage.