i have used mag sparks and think they are great!
Pedersoli also makes an identical product that is better fit and finish
i do not know of any mag spark or similar device that is made to allow the clearance of a cap and ball revolver -
Funny how sometimes withoput ever having used or even seen something firsthand opinions are formed or judgement as to worthlessness is cast (I’ve heard tell of a new tangled product of smokeless powder in a self contained cartridge with projectile - but whatever the use for
)
Although I typically prefer black powder the mag spark 209 ignition allowed me to use blackhorn which also with a sealed and secure ignition provided IMHO advantages hunting in severe inclement winter weather (I am not afield hunting only in fair weather.
iv’e successfully hunted with them on a different muzzleloaders of mine; shotgun fowler, rifle, and rifled musket.
Just my 2 cents worth - your mileage may vary and not the first abomination I have altered (easily retrofitted and removed) my traditional and original arms including to accommodate my aging eyesight.
I Hope this does not step on too many toes - but my feet only get sore from tromping the woods and hills