Have you found any issues with the CCI magnum primers? I purchased a box and had several misfires and hang fires. I mentioned this to the retailer and he said another customer had recently made the same complaint. Might have just been a bad batch?
Hey Mercer, I may be the other customer. Couldn't use the CCI Magnum Primers with BH 209 without misfires. One solution that works would be to buy the "special breech plug" suited for BH Powder with these primers (approx. $25). Instead I tried Federal Shotshell 209A Primers using BH209 and the original breech plug and absolutely no issues.
Just sighted the ML in last week and used Federal #209A Shotshell, 90 gr. of BH209 and Hornady 50 cal sabot .300 gr. Worked like a charm - accurate and no misfires, etc. btw I'm hanging on to the CCI Magnum primers in case I buy the BH 209 primer down the road.
PM me if you want more info.