Change Discovery Barrel

Has anyone tried to get a Maximus barrel to put on the Discovery? Will the barrels interchange and will Crosman sell the Maximus barrels?

I'm running out of ideas to get the Discovery to shoot accurately. I've cleaned the barrel several times, re-crowned the barrel checked for burrs on port and lead in the rear of barrel, played with barrel band position, etc. First two Discoverys I had shot very well but developed leaks and Crosman replaced the guns. This 3rd Discovery has never been accurate. It's out of warranty, so won't go back to Crosman. Tried about 20 different pellets, also.

I have M-rod, P-rod, 1322's, 2240's a 2289 and all shoot very well. But this Discovery is not accurate. Thought maybe a new barrel will be in order. I have over 40 airguns, and every one of the others will shoot circles around this Discovery. If I had any hair, I'd be pulling it out. 

I tried 4 or 5 different scopes also. The scope on the gun right now came off my M-rod and was very accurate on the M-rod, so don't feel I have a scope problem.
 
Running in the mid 700's to a little over 800 depending on hammer spring installed.

I won't even bother to measure the groups, they are so bad. At 25 yards, a golf ball would not cover a 5 shot group. At 25 feet in my shop, a quarter will cover 5 shots. That is with a scope taken off the Marauder .25 when I changed the Marauder scope to higher power. The scope on the Marauder did very well. I just went from a 3-12x AO scope to a 4-16x AO scope on the Marauder. I have two 2240's and a Crosman Mark 1 with open sights and shooting over a rest in the shop that will out shoot the Discovery with the scope.

Everything I have tried has convinced me the Discovery barrel is trash. One .22 Superdome pellet just fell through the length of the barrel by it's own weight. A check with 6 to 8 other pellets, they will slide through the length of the barrel by just the weight of the cleaning rod if the barrel is held vertically.

I've tried two barrel bands, three barrel bands with one of them inletted into the stock just past the air gauge, front sight installed, front sight off, TKO installed, TKO off. Just running out of ideas. I even considered buying a .177 barrel to replace the .22 barrel. I just really prefer .22s over .177s.
 
I'm in the exact same boat here. I got the Disco as my first PCP and have never been happy about its accuracy. Same thing, moved the barrel band around, TKO on and off, etc. I wish I waited for the Maximus due to the better shot string and just overall nice upgrades. I think I'm going to try to get a Maximum barrel and hope that fixes it. It is still barely within warranty, should I send it back to Crosman? Is worth the time and money or should I just get the new barrel?