You could get the Raven cylinder and get a new spring and piston for it, but the Raven cylinder is about £100 and the only part of the set I'd want would be the cylinder and the cylinder head, the spring, piston and guide it come with would be dead to me, so spending so much for 2 out of a 5 part set just seems stupid. I thought I'd made that relatively clear in my last comment.
I have a twist barrel cut for an L96 which fit fine and worked as it should. So any other L96 cut barrel ought to also fit.
Unless the person you were talking to on the sniper forums owns the gun and has tried fitting the barrel they're on about, I think it stands to reason that they're not a good source of info. The notches on the barrel are for the hop rubber, they don't lock into the barrel in anyway. The Hop grabs the barrel and then the hop unit grabs the rubber. They're the only retention pieces acting on the inner barrel.
Things I know are VSR compatible have been listed above in past comments;
Piston
Spring
Spring guide
Piston sear
Hop rubber
Hop arm
Everything else (trigger unit, trigger sear, spring guide stopper, the actual hop unit itself) with the exception of the PDI cylinder set, either has no alternatives available, or in the case of the barrel, is TM L96 compatible.
