By "silicon ring", you mean the rubber o-ring?
That leaves the metal gas rings.
Late model 1100s and 1187s use a so-called "one piece" gas ring. It's actually two gas rings. They are interlocked together. Be sure to reinstall them with the gaps on opposite sides to prevent pressure bleed off. The flat end goes towards the breech, and the stepped end towards the muzzle.
These can be readily replaced with the older two-piece rings. I've never found a need to do so, but some guns run better with the older rings. I suspect the owners were not paying attention to the gap alignment of the new rings in many cases.