My omega will not shoot tight groups with any of the crushrib sabots for some reason about 2.5" at best but most much worst. With very tight sabots it will shoot 1.5" 5 shot groups with 100 grs BH powder and the yellow sabot that comes with the barnes 285gr spitfire. My bore was very tight as well but after several hundred shots seems to load easier now I use to think I was going to break the rod loading some of the sabots but now they go down much easier! My gun likes the 250gr Shockwave as well. I use the standard w209 primer with the BH and have never had a hangfire. No blowback in my omega. Love the gun!
100g of BH209, 250g Shockwave, Harvester High Pressure EZ load sabot (aka Harvester Short Black), Fed209A primer. Consistent 1" groups at 100 yds in my dads Omega. 110g & 120g also shot well but 100g is a little easier on the shoulder and the wallet.