Well I've always been told 5 gr increments.
.don't know why 5 gr but that's what I've always heard.
 I'll be doing some Chrono work, hopefully Saturday if the weather holds . Working up a load for my .45 auction gun.
 I'll try small changes and see if my old technology chrony can't tell the difference.
 I recently watched a video by lame beaver and he states BP is only about 45% efficient
Poking around the interweb seems to support that.
Kevin.
 

I like watching Mark?s videos on YouTube. He is always entertaining.

YAY for Beth Anney! - another year notched on yer gunstock! Hope you have a "bang up" birthday!

Per a viewer's request, I tried splitting a bowling ball using Swiss powder & then switched to Schuetzen powder.
I'm having entirely too much fun trying this experiment.

Most everything I've read about black powder claimed it was an inefficient burning powder. And I've read where chonographs cannot detect changes made by adding 1-4 grains of powder. So when working up a load for a rifle, I add or subtract in 5 grain increments. Am I correct in doing this or should I be adding or subtracting in 1-4 grain increments when tweaking a load. Everybody has an opinion, so lets hear what those opinions are.