With the cp barrel you will be able to pick up different sized backs and build a little kit for different sized paint. My lapco shoots great but is a little loud. I actually covered the porting with tape and use it as a rain barrel. After about a year of trying a ton of different barrels here are my personal thoughts. They all shoot about the same (I should have listened). My hammerhead shoots crappy paint a little better than a smoothbore, not $120 better, not $60 better, but I paid $20 so its cool to have. Crappy paint still shoots like crappy paint. My favorite barrel is a 16" All American, not because its better, because the outer bore of it is smooth without waves or divits or odd shaped barrel breaks. It seems to help line up a shot better having a clean smooth line to point with. Underbore works, overbore works, matched bore still kinda works. At the end of the day, pick what looks coolest to you.
Autocockers are not more accurate, I'm just more accurate when I shoot autocockers.