*H870 Duplex Loads in the 4570*

[jonp]

I've had good luck with 4759 and similar as a kicker. Also 2400 seems to work in the larger cases. I started with 1 gr and worked up from there making sure to separate the loads with a little tissue to prevent migration. Main powder is either Black with the 43 Spanish or 870 Clone from Jeff Bartlett.

[john.k]

I actually question if its necessary to keep the powders segregated .I do duplex loads into a separate container before tipping into the case .....I see this as a foolproof way of ensuring both components are used,instead of batchloading powderA,then repeating for powderB.

[Dapaki]

I actually question if its necessary to keep the powders segregated......

That's a very good question, one that I don't think I will be testing this round but if the hypothesis is that a faster powder is needed to assist the slower powder in getting a complete burn, does it make more sense to put it behind the main load in hopes that the flame would spread far enough to light all of the slower powder or would the overall burn be more complete if it's intermixed?

I am going to guess that most will speak to the point of the kicker being the easy to light powder and is use as a barrel and fouling cleaner when placed behind the main load. So far, this has proven true in my testing in the 350 LGD using W296 as a kicker yesterday. The barrel was clean but for a few scatter grains on the WC867, a departure from the all 867 load used as an analog, it was so fouled in a single shot that I could not push a patch down the bore and had to drip Hoppe's 9 down the bore and brush it all out.

[Dapaki]

I actually question if its necessary to keep the powders segregated ......

Yes John, yest it is. I am working on the 350 LGD today and threw your idea into the pot and stirred. Mind you, this is an AR in 350LGD so for me, cycling is imperative. The first shot was great! The action felt smooth, recoil was a little less but not much, the boolit hit a little high but very close to zero. The problem was that there was masses of unburnt powder everywhere! The second round would not cycle, the bolt would not close, the magazine release has powder under the arm and would not latch the mag for the 2nd shot. It was an over all mess!

Maybe in a 45-70 where you can run a swab down the barrel after every shot but you are getting a very powder fouled barrel with WC867 if you mix the duplex.

[john.k]

I would never use 296 ,its in my hard to light category.....in fact Ive been using 296 mixed 50/50 with trailboss as a light load in big cases ....accuracy is good ,but havent chrono'ed anything yet.Seems like if its important to keep the fast powder at the base,the slow powder might be moving as a solid slug ,burning at the rear.....which would eject any unburnt ,same as blackpowder does.

[rbuck351]

I have done a little work with 5010 and a kicker in a 358N. First I filled the case to the base of the neck with 5010( 76 gr) which compressed the powder slightly using a 200gr boolit. This left a lot of unburned powder. Next was to drop 3grs of 5010 and add a 3gr Kicker of AA9. This cleaned to bore a bit so worked up AA9 1gr at a time dropping the 5010 1 gr at a time until I got to 9grs of AA9. This cleaned the bore nicely but pressure and velocity were both climbing more than I wanted so I dropped back to 7grs of AA9 and 65grs of 5010. This load shoots fairly clean at a velocity of 2365fp. I tried a couple of other cartridges but haven't done a lot of work with any but here are some results with a 416 Rem

1 case full of 5010 84grs and a cast 365gr 1459

2 80grs 5010 + 4grs of W231 on top of the powder 1833fps

3 78grs 5010 +6grs of W231 on top 1937fps

4 76grs 5010 +8grs of W231 on top 2024fps

I did not test for accuracy but wanted to see where powder burn cleaned up and velocity. Also wanted to see what would happen with fast powder on top.

I have not tried it in m 45/70 yet but intend to when time allows. In my limited experiments it appears that the 5010 starts to burn fairly well at about
or 6grs of kicker. Also it doesn't seem to make much difference if it's over the primer or on top of the 5010.

I tried some smaller cases (22h, 223, 308) but didn't have good results also have been meaning to mix the two to see what happens.

Please continue with your experiments and post results. I have a lot of 5010 and don't plan on throwing it out.

[Dapaki]

*Update* The 350 Legend duplex was successful, 4gr Silhouette under 25gr of WC867 gave me 1600 fps with a 200gr cast boolit and a group of 3" with no gas check. I am sure I will tighten it up with some base work.

[indian joe]

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.

Nothing specially bold or brave about a duplex load with smokeless under black - I use a little 4227 as the kicker 5 grains in 38/40 (3 would proly do it but works ok) and 7 grains in 45/70.

[indian joe]

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!

got nothing to offer but interested - I have a heap of red dot and no use for it - duplex under blackpowder is my interest.
At present using 4227 as kicker and that works really well - if you can get a little compression in the load I cant see any of these kicker powders "migrating" in the load - certainly doesnt happen with my black duplex rounds. Only thing I would be a little leery of red dots potential to generate pressure - five grains would be a good place to stop I reckon. Anyways please post results - should be interesting and useful.
I also have a large can of WST - thought about it too.

[M-Tecs]

Nothing specially bold or brave about a duplex load with smokeless under black - I use a little 4227 as the kicker 5 grains in 38/40 (3 would proly do it but works ok) and 7 grains in 45/70.

Not only nothing special or bold about using smokeless as a kicker under black it is also as long a semi-smokeless and smokeless. The Rowland/Pope record is a good example.

[Wayne Smith]

Consider another variable. The US Army, back in the day, realized they had to crimp the 405gr boolit when they did not have to crimp the 520gr boolit. Not enough mass to allow the powder to all ignite, and they needed to retard the movement of the lighter boolit.

Same thing with loading duplex loads of slow powder. Consider boolit weight (mass/inertia) and crimp and manipulating those when you see unburned powder.

[earlmck]

got nothing to offer but interested - I have a heap of red dot and no use for it - duplex under blackpowder is my interest.
At present using 4227 as kicker and that works really well - if you can get a little compression in the load I cant see any of these kicker powders "migrating" in the load - certainly doesnt happen with my black duplex rounds. Only thing I would be a little leery of red dots potential to generate pressure - five grains would be a good place to stop I reckon. Anyways please post results - should be interesting and useful.
I also have a large can of WST - thought about it too.

I have had a bad experience using fast powder as the kicker for my duplex with black. 6 grains of WW244 under 69 grains black and 500 grain Lee. Case separated half and inch above the base and blew on up a couple inches into the barrel. Took a little persuasion to get the case back out of there as you can imagine. (I plugged barrel above case and filled with molten lead and then drove her out with a steel rod from the muzzle). Thinking this was some kind of a fluke involving a faulty case I proceeded to do more shooting and had it happen a second time (slow learner). I've seen warnings not to use real fast powders with duplexing with the black but no reasons given. I'm betting this "blowing a piece of the case into the riflings" is the reason for the warning. I now use 5744 or 4198 for my duplexing and don't use as much compression (that problem load used a lot of compression). Anyway, that's my story on why I'll stay away from black powder duplexing with something as fast as Red Dot.

And no, I have not had any such thing happen when duplexing with smokeless (I have gobs of 860 I use as a "combustible filler" for some of my cast loads). My kicker powder for 860 has been Universal, which is about the same as Unique for burning speed. Never a problem.

[indian joe]

I have had a bad experience using fast powder as the kicker for my duplex with black. 6 grains of WW244 under 69 grains black and 500 grain Lee. Case separated half and inch above the base and blew on up a couple inches into the barrel. Took a little persuasion to get the case back out of there as you can imagine. (I plugged barrel above case and filled with molten lead and then drove her out with a steel rod from the muzzle). Thinking this was some kind of a fluke involving a faulty case I proceeded to do more shooting and had it happen a second time (slow learner). I've seen warnings not to use real fast powders with duplexing with the black but no reasons given. I'm betting this "blowing a piece of the case into the riflings" is the reason for the warning. I now use 5744 or 4198 for my duplexing and don't use as much compression (that problem load used a lot of compression). Anyway, that's my story on why I'll stay away from black powder duplexing with something as fast as Red Dot.

And no, I have not had any such thing happen when duplexing with smokeless (I have gobs of 860 I use as a "combustible filler" for some of my cast loads). My kicker powder for 860 has been Universal, which is about the same as Unique for burning speed. Never a problem.

thanks for posting this ------I had a different bad experience with red dot which is why its still in the can at my place............awaiting further advice

[Dapaki]

I have yet to do the write-up on my findings but so far, I too find that Red Dot gives poor performance at lower charges then gets to energetic too fast using larger charges. I have used 4198 with great success but have found a surprise in RAM Silhouette (more on that in the write-up) giving me a clean burn, clean barrel, good speeds and no signs of high pressure.

Thanks all for your experiences, it helps a lot with load ideas.