Home Forums Hunting & Shooting BPCR Duplex loads

Curious about experiences with this, particularly with the .45-70.

It is a decent way to use up old stocks of Elephant powder....
Never replace more than 10% of the blackpowder load and don't compress the charge in the case.

Can you expand on the no compression caution?

Yup don't compress the powder charge at all, not even when seating the bullet.

Understood that, wondering why?

Pressure, most smokeless don't take kindly to compression. You've already dumped a 1/3 or more of the smokeless maximum charge in the case, and then finish filling the case with black. Which the black by it's own self would be running very nearly maximum pressure.
Duplexing is an interesting concept, but with no real practical application anymore. NRA rules prohibit any smokeless in bpcr/bptr matches, and if attending a gong match, and don't want to shoot the black, then just shoot smokeless.. Cause even with duplexing you still have to clean the gun and the cases.
Besides all that there have been some that swore that shooting duplex was a sure indication of that persons only prom date being their mom's baby sister....

Roger that. Is for a hunting gun, not competition in any case. Mom didn't have a baby sis, no experience with that.

I'ld still scrap the duplexing. Either work a blackpowder load that will shoot dirty, or just load smokeless.

I can do that too. Thanks.

Duplexing is just one of those things that are neither fish nor foul.
Interesting how duplexing became twisted totally backwards from how it began.
In the early days of smokeless, the primers that worked so well with black(they were much weaker than primers we know today) would not give a consistent ignition with smokeless, so what is a shooter with a thousand berdan primers to do? He dumps 2-3 gr. of black in the case and then finishes charging with the new fangled white powder. And hallaluah, he's back in the shooting business with his trusted old rifle and the new stuff some of the cool kids on the block are using.

IIRC, the primer manufacturers even marketed BP primers separately from the "new" smokeless primers.

I still haven't figured out why folks use a magnum rifle primer when shooting .45-100 & .45-120 when BP is so much easier to light.

Ed

The magnum primer thing pretty much came into vogue by misdirected attempt to replicate the original loads. The flash hole was drilled out in an effort to replicate the amount of spark that would of been directed to the powder. But the big mistake came from using the magnum primer.
A great number of folks that regularly shoot very good scores are using either a pistol primer , or a paper wad between the primer or the powder.

Sorta like they loaded the old battle wagon guns, hey? BP initiator and then the other stuff...recollection has it they weren't too accurate beyond 25 klicks.

A 16" gun putting a round within a 100 yard circle from 22 miles out qualifies it as the most accurate varmint gun around!

Ed

'cuz a book told us to

It did work, but Federal 215's aren't easy to find anymore, so I'll happily stick to std rifle match primers.

My load for a Rem RB 45-70 with Numrich barrel was 5 gr of DuPont shotgun bulk smokeless, 55 grains of DuPont Ffg, a milk carton disc, a lubed 1/4" felt and another disc. Seated the pure lead 457124 into the rifling.
Shot clean all day, 1 1/4 @ 100, 3 5/16 @ 200. Three patch cleanup.
Used alox lube from javelina.

I dabbled around with duplexing some time back but I never got the accuracy I got with just straight black. Yes it leaves a shiny bore but I did not stick with it to get a good load worked up doing it.
I tried RL 7, 3031, ball-C2 and H-380. I used a .22 LR case full of H-380 for a dipper and that gave me a very clean bore.
But for a hunting load just straight blk. and a none bore riding bullet I don't think can be beat. I can use many follow up shots using a flat nosed bullet with out a bore riding ogive.