shortening a barrel question...?

[DirtNap647]

i have a bps 10 that has a 28" vent. rib barrel on it, I would really just like a 24" barrel having the barrel cut off and then rethreaded for the choke does this have any effects, i was wondering if the barrel is still the same dimensions or does it taper so cutting it may make it more open ...anyone have it done,  any input would be appreciated...?