I'll echo what others have said...

You can, in fact, shoot a shotshell out of a rifled barrel. Your results however, well.....inconclusive. Certainly not good enough to do the job ethically.

You can get aftermarket barrels though (assuming yours is rifled). You can look for a rifle-sighted camo model with Rem Chokes. Expect to pay bw $200 and $300 for it though.