Crosman Challenger shoots a pattern not a group? Is it me?

Just picked up this rifle and have put about 300 rds. through it. I cleaned the barrel with felt pellets before shooting it for the first time. Cleaned it again when it didn't group. Tried Crosman Premier 10.5 and regular, H&N Terminator, RWS Meisterkugeln and H&N Barracuda. Same 1 3/4" pattern at 33' regardless of pellet. I really want to like this rifle, what can I do? Costs around $60 shipping to sent the rifle back to the dealer. Is there anything I can check with out taking the gun apart? Thanks for the replies.
 
You should get 1 .22 hole at 20 yards with that gun. Clean with patch worm and put 30-40 rounds in to season it. Don’t clean it too often because it’s really not needed. Brown box domed pellet would be most accurate and then 7.4 grain pointed are really accurate out it too. Mine came with this card and it is that accurate. 
13EF8A58-42C6-491D-9A94-FA247DFDF029.1613855951.jpeg

 
I'd definitely recommend trying JSBs also. In general find them being most accurate out of all my guns. The JSB Simply wadcutters are very accurate out of my 1701P at 10yds like same hole with red dot. And price wise there same price as Crosman pellets in the tins which my 1701P also likes. Haven't tried my 1720T yet but assuming it will likely do well with them also. They have the same LW barrels as the Challenger just shorter lengths so something seems off to me if yours cant do better than that at 33ft.
 
The reason I asked about how fast is because I have a couple .177’s that have definitive speed thresholds. The moment I go over 900fps the groups open up. If I have the gun set to shoot anything over 10 grains, I can’t even shoot anything lighter unless I turn the gun down.




the challenger factory tune is 550fps so portably not going too fast.
 
The reason I asked about how fast is because I have a couple .177’s that have definitive speed thresholds. The moment I go over 900fps the groups open up. If I have the gun set to shoot anything over 10 grains, I can’t even shoot anything lighter unless I turn the gun down.




the challenger factory tune is 550fps so portably not going too fast.

Oh ok. That name rang a bell now I think I know the gun. Aren’t they like a 10m training rifle or something? Should be very accurate as long as you don’t stretch it out too far. Sorry peep, should have thought more about your gun. I have Fortitude on the brain for some reason.