The CP 1 Piece is a larger bore barrel, so it will fit most any paint. It is also an agter market barrel, and because of this, more effort has been put into its manufatureing. Its microhoned uber good, so theres less friction and the ball is lined up happier. The barrel is also ported so theres less noise. U could have a better stock barrel of u stuck a piece of pvc pipe on the front of the gun
porting, better honing, more customizable and the ability to choose bore sizes. CP sells these for money so more care are put into them then a barrel that is just thrown onto a gun in order for it to be completed and sold. cp's barrels are there bread and butter so they make them great.