H&R ultra slug 20 gauge misfire

Went to the range and had 3 of 10 rounds misfire. I have read that it's a manufacturing defect, any recommendations on a gunsmith in DFW that can get me squared away for my upcoming Iowa hunt?
Thanks to all

Doc's in Carrollton would be my 1st stop...just south of the Bush @ I-35E...then Larry Pockrus in Ponder north of TMS off of I-35W
Ron

I called manufacturer and they requested that I send it back. Stay tuned, hopefully they will resolve as any quality company would. Will post update when available.