You should get way better performance out of a comp-n-choke , they are expensive but worth the money, the ulti-full choke will do ok out to 35 yards, but then it will drop off. I've found out the hard way and bought all of the cheaper chokes and spent over 300.00 over the years. I should have bought a comp-n-choke right off the bat. There are about 60.00 for a choke tube, the good thing is that thay will let you send back the choke for a refund or another choke that will work for you after you shoot it. So you can eliminate the restriction sizes one by one with only paying for one choke, all you have to do is pay shipping. I would start with a .660 if your barrel is 24in and go higher to a .665 if your barrel is 26 or 28in long. Since the barrel is shorter you need a tighter choke to keep it together at longer ranges. A little more open for longer barrels. As for shot, go right to X-tended ranges 3 1/2 6's they will blow you existing pattern away by 50 plus pellets at 40 yards, let me know how you do.