Thoughts on duplex load

[BBerguson]

I use to feel that way and I think I have posts on this board saying that. I guess I still feel that way about powders that are vastly different in burn speeds. Like a Bullseye-Lilgun combination. The duplex loads I’m talking about are basically the same burn speed powder but one (Lilgun) seems harder to ignite than the other (IMR 4227). This is in a 450 Bushmaster case with a small primer pocket so I thinks the primer is struggling to ignite the charge.

I haven’t done this yet. Still listening to opinions and researching. I do appreciate all of the feedback, it’s the reason I asked here.

 

[RBHarter]

Ackley's hand book has duplex data for the 45 Mag (later known as 454 ) .

 

[fiver]

it was also known as the 450 express magnum.
it didn't need more than one powder to work.
BTW i have 50 NAA factory rounds if anyone has deep pockets and wants them.
i also have maybe 50 home made cases [some still loaded] if anyone needs them.

i did get a good history lesson from Dick when i mentioned having the revolver.

anyway the key to duplexing is to use a minimal amount of a much faster powder to get the slower powder going properly.
i'd use like 3grs. of red-dot and a slow enough powder to 100% the case.
anything other than that... and it won't work properly.
the fast powder is just there to ''up the brisance'' of the primer [bring the initial pressure up] and insure ignition.

 

[John]

I have successfully duplexed WC872 and 860 with 30-06 based cartridges. max was with 6 gr of fast rifle powder. I think your case is too small and your powder too fast for this.