Front Cylinder Ring Necessary?

Mine didn't even have one, but I would test her out and see how it works. If it does not cause any problems, might not even have to worry about replacing it with anything.

Yes, you do. It works as a spacer so that you don't screw the outer barrel in too tight. It also reduces bolt pull, I have found.

A little thing that I did to a friend's was to carve grooves into it, then put grease in there, and it would regrease the cylinder every time you charged the rifle. Make sure the grooves are frim bolt to muzzle, so that nothing happens with the cylinder catching.

It also prevents the cylinder from tilting much, which is important to maintain proper sear engagement. I have even seen guns that were missing the ring slam fire until it was replaced.

I throw mine away and never use them, been running 2 years without one on my mb05 and probably over 5k bb's through it, and about 6 months and 1k through my mb08 without it.