Try Ronnie Sunshines, it is primarily airguns and clothing but I got a very good rifle case from him for £26, semi rigid due to the foam lining canvas quality. I can get a Remmy varmint with bi-pod and T8 fitted in it and opened up it acts as a very good mat on the fireing point.
Aim field sports do what is becoming exepted as the best bags of this type. The Guy who designed them is a mad keen rifleman, they are built like - well you won't break the connection points and smash up your gun.and i seriously doubt you could wear one out period !
Its designed around the Army's L96 AI so loads of room. In fact if I'm stalking light I just fill the pockets up and wear it like a rucksack. Its also less noticable worn like that when people are about.