I got a very good condition QB78 carbine in today and have, of course, a few questions.
Firstly, the barrel moves up and down when grasped by the brake and llightly jiggled up and down. I see a barrel band, and a set screw near the breech. Are these the only two connection points, or are there screws under the stock that make the barrel tight? Anyone shim the barrel to make it stay in place?
The set screw near the breech comes above the surface of the receiver. Is that screw supposed to be flush or below the top of the rifle? And what size is that head? It seems to be between metric sizes. None of my hex keys fit properly.
Secondly, is there a metal replacement for the barrel band? The plastic seems soft and tightening that screw seems like a recipe for trouble. This rifle has a factory muzzle brake which would need to be removed to remove the barrel band easily, but I don't see any set screws on the brake that keep it on...I assume it is glued.
I'd like to put open sights on this gun to take barrel movement out of the equation, and to make it easier to load pellets. The scope is on the receiver (ie out of line with the barrel when it moves) and gets in the way of loading. The muzzle brake means that standard sights are out of the question. Anyone have a solution to keep my sighting system on the barrel?
Cheers!
Kris in NY
