Use real Black, problem solved.
If you hunt or have a finicky rifle like a Sharps or 61 Springfield get a nipple primer and use 4f to put a few grains inside the nipple to create a sure fire little "flash" in the channel.
I've been shooting original '61 Springfields in competition for 35 years and have found them to be every bit as reliable as a supository gun. I've had a half dozen cap (RWS) failures and the few other times the gun failed to go boom it was strictly my fault like not fully drying the bore when cleaning between relays and a couple of times I forgot that black stuff that makes smoke. I've had a higher FTF rate with .22s over a lifetime. I bought my wife and myself nipple primers, filled them with 4f and in 25 or more years neither of us has ever used one.