*H870 Duplex Loads in the 4570*

[Dapaki]

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!

[Nobade]

I've seen pressure issues using red dot as a kicker. I much prefer something like 4227 or RE7. But if you must, I'd start at maybe 4 grains and work up until you get a clean burn.

[Dapaki]

Yupper, I have 4227 and can try that. I do think it will migrate into the H870 though.

[Texas by God]

I hope it goes Sha-boom instead of Ka-boom! Be careful and good luck.

Sent from my SAMSUNG-SM-G930A using Tapatalk

[Hamish]

What was common knowledge just a few years ago now brings the Nellie's screaming,,,,,

I know several personally and have read many posts on this forum of 4198 being preferred. Me, I'm a big sissy, no kicker needed.

Typically, 5 grains seems to be about max needed.

[MT Gianni]

I agree with fast rifle powder over slow pistol powder. 4198, 3031 ranges are better for what I have used but never in 45-70.

[Dapaki]

What was common knowledge just a few years ago now brings the Nellie's screaming,,,,,

I know several personally and have read many posts on this forum of 4198 being preferred. Me, I'm a big sissy, no kicker needed.

Typically, 5 grains seems to be about max needed.

I KNOW I have read about complex duplex and triplex loads decades back, I even belonged to the now defunct Buffalo Classic BBS back in the day and we spend weeks working loads for the 405 but I never grabbed any of the data as I was super happy making BP and mopping the bore. Now I want to spend the time working on something new, find out what this pull powder will and will not do, so I greatly appreciate any and all offerings (positive) including the reminder of 4198 being a good go too! Thanks for the reminder.

[Dapaki]

I agree with fast rifle powder over slow pistol powder. 4198, 3031 ranges are better for what I have used but never in 45-70.

What chamberings did you use it for? I am hungry for all data.

[Maven]

Dapaki, Maybe look up Ross Seyfried and his writings about duplex loads?

[Dapaki]

Dapaki, Maybe look up Ross Seyfried and his writings about duplex loads?

Thank you Maven, I came up empty except for reference to his writings, do you have any links or text I could peruse?

[DonMountain]

I tried developing loads of 5 grains of Red Dot under a case full of a similar 5070 powder. Even after filling the case up to and slightly compressing the combination, I found that a lot of the 5070 powder just blew out the end of the barrel unburned. There just wasn't enough pressure in the case to make it burn properly. And accuracy was very poor as in 3' diameter patterns at 100 yards as opposed to 2" at 100 yards in my normal loads in my 45-70. Even burning it in my 338 Win Mag with 250 grain jacketed bullets didn't make it burn very well and I got poor accuracy. It takes more pressure then what a straight case and lead bullets can provide.

[MT Gianni]

What chamberings did you use it for? I am hungry for all data.

30-06, there is or was data on Castpics under surplus powders.

[Maven]

Sorry, but I didn't come up with a specific link either, Dapaki.

[Dapaki]

Thanks all, at least I have some hints and nudgings, I will report back on what I came up with and my results.

[Dapaki]

FYI- I did get some hits from MUSTANG's old posts on duplexing. I have lots of ideas, I just wish I could write as well as he does!

[Rapidrob]

I've used three grains of 5744 and a slightly compressed charge of H870, Magnum primer, flash hole slightly enlarged one drill bit size, in a .40-65-400 and got good results.

[richhodg66]

I did what you're talking about with my .458, heeding Nobade's advice, I used slower powders for the kicker, seems like I used 5744. Honestly, my accuracy was better without the kicker. I used magnum large rifle primers, the Lyman 500 grain round nose and loaded what is a slightly compressed load and then crimped a little more than I would have normally for a bolt gun. Accuracy was good. I did get some unburnt powder, but not much and it wasn't a problem.

As to the safety thing, at least without the kicker charge, I doubt you could fit enough of that stuff in a case to be dangerous. That load of mine gave no extraction problems and the primers looked very nice. No idea what the velocity was and I don't care. I wish that stuff was still available dirt cheap like it used to be, fun stuff to mess with.

[MT Gianni]

http://www.castpics.net/LoadData/Surplus/default.html
With surplus powder the rates of WC 860 and WC872 were both extremely close to 870 powder.

[FLHTC]

All you guys have bigger stones than I do. I met an older gentleman one time about 10 years ago who was selling off all of his reloading equipment and ammunition. He had about 500 rounds of 4570 loaded up with duplex loads. I can’t recall the grain weight but he was using 4350 and black powder. All I could picture was looking down at my hands and seeing nothing but a pinky left. I’m not trying to be a powder Nazi or any of that. I guess when it comes to this, I could not run with the big dogs I’ll be the first to admit it.

[flounderman]

I talked to a man on the North Dakota border with Canada. They were using the surplus wc 860 and 5 grains of red dot