It depends on your intended use for the shortened barrel. Of course, shortening the barrel will eliminate the adjustable chokes (if that is what you have). If it is a fixed-choke barrel, you will get rid of most or all of the bore taper, by shortening (thereby eliminating any choke effect). If you are making a slug barrel of this.... it will do just fine. I made a slug barrel of a vent-rib, Rem. 870 barrel (shortened to 21")...and it worked very well. This is because you generally do not want any choke for a slug barrel.

If you are talking about having the barrel re-choked when shortened (a new, adjustable choke system installed)...then you will be able to get similar performance to the original barrel... with one proviso. Generally, you will have to use the next tightest choke size (below the one you normally would use), in order to keep about the same patterns. I.E., if you normally used a modified choke for a certain type of shooting....then, to keep the same pattern-size, you'll likely have to use at least a super-modified....or even full choke. But, if this is taken into consideration, the shortened barrel can be made to work well.

Whether you do the shortening yourself....or have a gunsmith do it... do pay attention to properly re-crowning the muzzle. By this, I mean that the muzzle end should be exactly perpendicular to the barrel. If not, this will throw off slug accuracy....and very likely, shot patterns, as well. Many people think that this doesn't matter with a smooth-bore barrel....but it DOES. I know this, from personal experience.