I was looking around on the Blackhorn site and noticed this

"No. #11 and musket caps do not provide sufficient ignition for Blackhorn. However, a priming charge of 5 grains of black powder may be used prior to loading Blackhorn 209 that will provide reliable ignition."

I remember MD posting about duplexing and it went on about the safety issuses.

They cant seem to decide on their recommendations

http://www.blackhorn209.com/specs/primers/

So i guess you can but it is not recommended. After watching a primer come apart in a non recommended plug, i will play it safe until its well tested.

BTW it seems like they are finally publishing what many of us have known for awhile now about breach plug designs and proper primer head spacing.

http://www.blackhorn209.com/specs/ignition-guidelines/

i got the thumbs up from blackhorn, there was NO safety issues with using a 5 grain booster charge of jim shockeys gold to help boost the blackhorn.
http://www.youtube.com/watch?v=g5lmjSHJNxk

I see no issues with duplexing powders,it's been done for years in smoke poles.as long as the person is experienced and doesn't get carried away with the booster charge. for a hunting load it isn't very practical, especially if a second shot presents it's self. MD did you ever do any testing with the Shockeys gold super powder? Ray

no i didnt, i cant find it at any stores.

http://www.prairiearms.com/ Thought you had tested it already is why i asked! Ray

I find that my definitions do differ some what with some of the usage. to me there is a big difference between a duplex load and a primer charge. A primer charge simply ignites the main charge like any other kind of primer. A duplex load is a mixture of smokeless powders.

I think you are correct there pal.

Duplex loads--Keep upping the charge until just before the barrel explodes,then back off 1/4 grain.Not recomended for the faint of heart.LOL

Charlie