Most any firearm will make somewhat odd sounds during the break-in period, which I suggest you enhance with a thorough cleaning before doing too much shooting.
After adding a Limbsaver #10402 to the Nova, plus Mercury Filled Recoil Reduction Kit to the rear stock, and a 2nd Mercury Filled Recoil Reducer in the forend (takes the place of the hunting plug), my 3 1/2" camo Nova shoots like a dream.
Getting great results with a Benelli Nova pump and HS Strut Undertaker .665 and .675 turkey chokes (only $19.99) shooting Winchester Supreme High Velocity 3 1/2" shells (2-oz. #5 shot).
IMHO:
The Rhino chokes at $99 and the $39 Primos Jelly Head chokes are probably a little better; budget minded shooters should give the Undertaker a hard look.
Steve
P.S. Also bought .675 and .700 Undertakers for waterfowl.
....and www.HeviShot.com and Remington both state on their website FAQ's that the best / tightest patterns with Hevi-Shot come from .675 extended chokes.
HS Strut's Extended Undertaker Turkey Chokes come in .655 and .665 constrictions.
I just bought the following from them:
* Turkey - .665
* Waterfowl - .675 and .700