I have a buttload of H867 (sorry, it's not WC870, I missed a number in the OP) I picked up for $5.00 a pound and would like to work up 4570 duplex loads using Red Dot for the kicker under 405gr HB and the 500gr 3R in my H&R Buffalo Classic.
(First off, please dont reply if you are a "safety nazi" or panic person, the ever dying nay-sayer or the negative-Nancy sort, I understand the risks, I have 35 years of reloading behind me without one accident and I am willing to do the work to run long ladders looking for pressure issues.)
Why Red Dot? Red Dot is not pressure dependent, it has large flakes and will not migrate through the H867, it creates known pressures per volume and has a long history in reloading. Yes, I can use 2400, 335, 110, 296, 4198 and others if need be but I want to get your experiences using smokless duplex loads and real, boots on the ground data if it exists.
One of the benefits is that this powder (20mm Vulcan pull) cannot overcharge a 4570, worse case, it will come out like a Dragon Fire shell and light the yard on fire (well, not this spring, I have standing water over the range due to the 8" of snow that fell this week) so it's all good. I would love some speculation and if you have it, some workups through the reloading software out there if it allows for duplex workups.
Motivation? Current BP prices are $10.00-$15.00 lb, smokless is unobtanium around me right now and I have time on my hands to play around with this for a week before SWMBO figures out what I am doing and gets me back on the "honey-do-list". Lets see what you got!