You were hesitating because you didn't know enough to evaluate the risks. Smart man. You asked here (not the best resource on firearms, but some of us actually have experience and knowledge worth picking our brains - a dedicated muzzleloader site probably would have been better), and got a lot of advice. You thought about it, and decided it was worth the risk to try it.
Only other thing you might have tried short of taking it apart or pulling the bullet would be to bench rest the gun, sand bag it to keep it from moving, run a string to the trigger and pull the trigger from behind a protective barrier just in case you had a catastrophic barrel failure. My father had a jig with a long sting setup that he clamped his black powder pistol creations in, double or triple charged them, and fired them to test.