The bh209 breech plug will ignite it 100% of the time,the stock one won't. A good starting sabot and bullet would be a harvester crush rib sabot and a hornady 300gr non mag xto. Your better off buying both separate as it's much cheaper the buy pre packaged. I've been a stainless fan but seems the industry is going towards a coating like nitride. I do believe people are adjusting the firing pin bushing to get a perfect crush fit on the primer. If I'm not mistaking they sell a shim kit too. Good luck, make some smoke !!
https://www.harvestermuzzleloading.com/products/crush-rib-sabots
https://www.hornady.com/bullets/handgun/45-cal-452-300-gr-xtp#!/