I have two older (2002-2003) Omegas that are not particularly tight-bored like I hear the newer Omegas are so bear that in mind...
Omega #1 was bought new in 2003 and has well over 1000 rounds through it.
The best group it has ever shot was with 100 grns. of 777 3F and Barnes 285 grn. Spitfires--3 shots touching, under 3/4" center to center.
The most consistent load is 2 777 50 grn pellets and Hornady .430 300 grn. XTP's in Harvester Green sabots--many groups under an inch and about a dozen dead deer killed from 15 yds to 170 yds. It's a great hunting bullet.
This rifle also shoots Sierra .4515 300 grn bullets in MMP HPH12 sabots with 777 very well, but I hunt with the Hornadies.
Omega #2 I just bought this past winter from a friend who wanted to get a Triumph. The Omega was originally bought in December 2002, but was only fired about 50 times. I have been shooting only Blackhorn 209 in this rifle and so far, after about 180 rounds, it likes:
Hornady 250 grain SST's in MMP HPH12 sabots and 100 to 110 grains of BH209 with a Fed or Win 209.
This load stays within 1" to 1 1/2" consistently.