"On the inside, the replica, apart from the Hop-Up chamber and the magazine, is fully-compatible with a popular on the market VSR-10, which enables an easy power tuning and a broad availability of spare parts. The adjustment slide for the Hop-Up chamber is located on the replica chassis, which enables a very simple and quick setting of the BB spin."
^ From the product page on Gunfire.
Range and Accuracy is a result of a high quality finished barrel, a decent hop up bucking that can lift heavier BBs than you are using now.
Also increasing the FPS of the gun helps, though that is not as effective as sorting out the hop up.
I believe that the hop up chamber is proprietary in dimensions, I imagine its still a VSR style chamber, so I imagine you can use VSR buckings and barrels. But you cant replace it with an aftermarket chamber. You can probably TDC mod it and teflon tape the bucking to the barrel to improve airseal.