mdbrown
MC-Don - that is not as far as thought you might be.... spent a lot of time in that area when I was younger. I am in Moscow now - came here to go to school in the 60's and ever have left - The plan was to return to Boise - but it got to big... Hey if you come noth bring yer gun and we will go do some shooten...
Suggestion.... Call Dave at No Excuse... order a box of his No Excuse conicals and give them a shot. I use 90 grains of T7-3f in my GM-LRH-SS sidehamer which is a 1/28 twist and in the other sidehammers i use 80 grains (1/48 twist).
http://members.aol.com/nebullets/
Since you are limited percusson cap ignition - I would suggest the 3f powder as it is a lot easier to ignite, oops forgot you were using a pyro so that should not be a problem.
hope you get something to work for you.... As much as I dislike the PB the 2.75 group of 405 grain is not all that bad with open sites @ 100 - they will work just fine... most often when shooting pure lead - big lead is the way to go...