Even though it was after the gun cooled and was swabbed, I was impressed by the duplex loads of homemade with only 5 grains of 777.
One question I have is about compression.
You said that you filled the cases 1/8" from the top.
After that, how deep is the bullet inserted and the amount of compression that results.
Wouldn't the [re-enactor] powder be compressed more than 1/16" - 1/8" after the 250 grain bullet is loaded?
I thought that one recommended amount of total compression was supposed to be 1/16" - 1/8".
Could that create some variation with the re-enactor powder and the 250 grain bullets if the powder is getting crushed instead of compacted?
I realize that powders can be compressed as much as a person wants, especially home made powder if it's fluffy, but could any extra compression with the re-enactor powder also create velocity variations?
Do you fill the case to the same height no matter which size bullet that your loading which affects the amount of compression?
I wonder how a duplex load would work with the re-enactor powder?
Have you ever used a filler or considered using one to obtain compression while loading slightly less powder due to the addition 777?
If a little bit of 777 can boost powder performance with less compression, then maybe the case can be topped off with a little bit of filler which would help conserve black powder.
And if more compression does help to increase velocity, then the filler would allow for some extra compression instead of using extra black powder to fill the case.
Every grain of filler that replaces black powder in favor of 777, might be cost savings if such a small amount of 777 can boost velocity.
I don't reload, but I figure that extra compression may be a two way street.
I'm not sure if it can create more variation, more velocity or both, depending on the powder and bullet or not.
But that must be the fun part of having a Chrony.
The same would apply with straight 777 cowboy loads which you said were hot, using filler with less powder could help to adjust the velocity and provide another option to always needing to rely on duplex loads in the future.