stcspiderman
OK... let me start off by saying right up front I am way biased... The Omega, even the Z5, is one of the best ML out there. In the past they have have had minimal problems, excluding a run of non-concentric alignment of the QLA with the bore.
Mechanically they are very simple rifle. There are a couple of things you can do to make them fundementally better very easily. Some stock work and a switch to a 25 ACP breech plug, even the conversion of the existing plug with a Lehigh Vent liner. But none of that is an immediate need.
Couple of thoughts for you, if you go with this change, which I would in a heart beat... you might also think about switching projectiles, maybe going to a .452/250 grain Speer Gold Dot/Deep Curl and a sabot. Right now I would suggest a Harvester 'Crush Rib' until you find out how tight your bore might be. Even cleaning and polishing the bore will help a bunch - actually shooting PB out it will polish the barrel.
Most Omega's will shoot just about anything you put down the bore other than in some cases conicals.
Both of mine, a regular Stainless with thumbhole and a blued Z5 shot great with a 110 grains of T7-2f and either a 250 grain or 300 grain bullet... Shoot I forgot they shot 40cal 200 grain bullets lights out.
Remember I am biased but totally positive about the Omega especially compared to a CVA...