I have two double rifles both .50 muzzleloaders but lots of fun .One is a Kodiak the other is a cva express rifle.I put double express sites on both of them and small rifle primer adapters that make them go off as fast as a smokeless hammer gun .I always wanted a 405 win double rifle but it was never in my budget. I WILL probably sell these two soon I can't shoot over 25 yards anymore with open sites. I USE TO be able to hit clay targets at 75 yards with both of these .I learned alot from these two rifles alot of work but easy to regulate with the double adjustable sites .

I have a Cva 50 sxs with 12 ga barrels as well. Only one sight, took me a long time to figure the right load, bullet, etc. Each barrel shoots well on their own. Got it down to about minute of grapefruit at 50 yds. Great fun. Had a number of doubles from 30-30 to 500-415. Once you've been bit, it's over.
Cheers
Rick