There are three excellent buys going on at Bass Pro right now. One is the H & R Sidekick for $149-- another is theKnight Disc Elite 45-cal for $199/$249 & last is the T/C Omega for $299. The Firebolt you are looking at is a discontinued model. There's very little difference in shot-groups/distances having both barrels. Accuracy can be suspect & the action creates excessive blowback & fouling that impedes movement quickly.
Just my opinion based onowner replies/troubleshooting threads on boards like this one.
http://www.basspro.com/servlet/catalog.SubClass?hvarDept=400&hvarEvent=&h varClassCode=3&hvarSubCode=1&cmid=HULN_OS_ BLACKPOWDER_BLACKPOWDERGUNS