Duplexing WC860

[curator]

Finding Reloder22 to feed my 6.5X55 Swede has not gone well this past year. I have had good accuracy using WC860 but disliked the unburned granules left in bore and chamber even using Buckshot's "860-flick." Recently I tried a "kicker" load of 3 grains of SR4759 (Lee dipper .3CC) under the full case of WC860 with the 140 grain bullet providing a tiny amount of compression. WoW! No more unburned powder, great accuracy, plus an extra 200 fps over what I was getting without the kicker. Primers show the same low pressure I have come to expect using this very slow powder

With this success under my belt, I tried the same approach with my .40-65 BPCR using 380 grain cast. 3 grains of SR4759 under 42 grains of WC860, card wad and seat bullet on top with light crimp. Great accuracy, clean burn, same POI as 60 grains of Goex FFg without the cleaning of gun and brass. No high pressure signs judging buy the rounded primers. Other than the extra step in the loading process, it appears this will make using my store of WC860 more enjoyable.

[bruce drake]

Good bit of information to know since its the only surplus powder I see for sale a lot of times now.

Would 2 grains of Red Dot or Unique be an ok substitute for SR4759 in 8x57 and 30-06 cases?

[curator]

Bruce Drake:

I don't know abut using Red Dot or Unique to duplex WC860. I have seen others post that they have used W231 (!) and IMR4227 as a "booster" when loading WC860. I chose SR4759 in part because I have some experience using it to duplex black powder loads in various cartridges like .40-65, and .45-70 to get a cleaner burn. Perhaps others on this forum have experience to share. With these "Cap'n Kirk" loads (to boldly go where no man has gone before) go slow and use a strong gun and relatively new brass.

[Jailer]

The possible issue with using flake type powders is with them mixing in with the rather coarse ball powder even with a compressed powder column. Using a fast stick rifle powder helps keep it over the primer and do it's job of acting like a large primer.

I use a small charge of 4198 with my WC 867 duplex loads in my 45-70. It's a nice mild shooting and very accurate, consistent load.

[waksupi]

I've used various slow rifle powders for kickers with WC 860. Worked fine.

[bruce drake]

I've got plenty of 4064 to use as a kicker then. Thanks for the introduction to this.

[madsenshooter]

I've used Blue Dot, and I tried VV 10B101. The 10B101 didn't work well, sensitive to compression and I could tell from the cases that there was a lot of pressure down at the bottom where the flakes of it were at. In theory, one should be able to use a fast burning powder and get the pressure up to the level that the 860 is meant to burn at. The fast powder would simulate the much larger primer that the 860 is usually ignited with. Someone started working on that theory at one time, then had to stop. I used Blue Dot in the 6x45 at 17% of the total charge. That got me 2300fps, single digit SDs, and some pretty good accuracy out of the caseful of powder.

[curator]

Madsenshooter:

You make a good point about the larger primer WC860 would be ignited with in the 50BMG cartridge. I tried Federal 215 Magnum primers and got a little better burn but still had a LOT of unburned powder in the bore.

[cga]

Fascinating information!

I would love to try some duplex loads in a 1895/45-70, with 405g. cast. I also have SR4759, along with various pistol powders that could be used for the booster. What would be a starting charge for imr5010 or wc860. IMR 5010 is what I have the most of. I also have H50bmg, 867, 872, aa8700.

Any information would be greatly appreciated.

[madsenshooter]

I'd start with a 3-5gr booster of the fastest burning powder you have (better for simulating the flash of the larger primer) and fill the case with 860 enough to compress the powder column with the bullet just a tad. Work upward with the booster from there until you get what you want. In straight walled cases, most of the guys with more experience using them, use the booster as a way to get the 860 up to where the load can be compressed. Either way will work. Fast burning, hmm, maybe I've finally found a use for that blank powder.

[MUSTANG]

Here is a table I made a year ago or two ago that includes flake powders as a Booster in Duplex Loads using wc860 in .223/5.56's. I do not have chrono results, but have recently been using a 3.0 grain kicker of Hi-Skor 700X in my .223/5.56 loads. I prefer Unique in this application, but have difficulties in locating it.






I have also had food results when loading .308's with WC860; but 5 Grains of Unique. All my loads using WC860 (or WC870 or WC867) plus a kicker are compressed loads. No pressure loads with these, and accuracy is fair with several different cast boolits sized for specific rifles.

[madsenshooter]

That's the fellow who was working on it!

[cga]

Thank you madsenshooter and MUSTANG for responding.

So if I'm reading this correctly, the charge of wc860 does not increase from slightly compressed, just the booster charge does. Use the fastest powder I have for the booster charge. (That would be Nitro100) What do you think about imr5010? Kernels too large to keep the booster charge from migrating into the main charge? Or the compression should hold it in place.

Also, in MUSTANG'S chart, shot #5 under Green Dot, shows a jump of over 200 fps from the previous 4 shots! Should that be 2256 fps?
24g. of wc860 and swaged bullets is almost shooting for free.

Anyways, I'm off tomorrow and will try this out.

[madsenshooter]

Right, the charge of 860 decreases the same amount you increase the booster, maintaining a bit of compression. I've never worked with 5010, can't comment. I figured the big, somewhat flattened balls of 860 would hold the flakes of Blue Dot I used in place, they tend to orient themselves in a flat pile. I also have no idea about the granule size of Nitro 100. You'll have to be the judge of whether or not the combination will work for you. Maybe you have a plastic tube around somewhere you could experiment with. You could also take care in handling the ammo if you thought you needed to, keep it base down until you load. If you're going to try it, be especially careful not to double charge with the kicker.

[cga]

I think N100 is just a little faster than Bullseye, and is a flat/disc shape, like blue Dot, Unique and Bullseye.

[cga]

Well, I tried a few loads. CCI std. large rifle primers, nickle Starline brass with a good crimp. 405g. cast w/gas check (.461) Lyman 50/50 lube.
Rifle - Marlin S/S Guide gun. Mold - RCBS 45/405/fn.

(1)50g. WC860 with 4g. AA Nitro 100

(2)45g. IMR 5010 with 4g. Nitro 100

(3)50g. IMR 5010 with 3g. Nitro 100

(4)50g. US869 with 4g. Nitro 100

(5)50g. WC868 with 4g. Nitro 100

Load 1,2 and 4 recoiled like 25g. of 2400 with a CCImag. primer, my standard load.
Load 5, slightly more recoil than loads 1, 2 and 4.
Load 3, to much 5010 for lite compression of powder, and heavier recoil, but not excessive.

Stopped with load #5, I didn't see the need to test H50bmg, WC872 or V.V.20n29.
The primers were not flattened, the brass expanded like my normal load of 2400, and no un-burnt powder left in the barrel.


Many thanks to madsenshooter and MUSTANG for your help.
Cliff.

[cowboybart]

Great Thread!!
Can the same theory be applied to larger cases/high pressure rounds?? I'm thinking 338-06AI and 264 Win Mag.

[madsenshooter]

An overbore cartridge like the 264WM won't need a whole lot of booster, one can get near jacketed velocities using straight 860 in the 6.5x55, for example. But in general, starting low with the booster and working up should work. At some point, you're going to get the 860 burning at the pressure it was designed to burn at. A chronograph would be very helpful in developing the loads. I think it best to use shotgun powders in this application as they aren't sensitive to compression. I can use the same amount of Blue Dot as I do 10B101 without getting the pressure signs 10B101 gives me, though the powders burn at about the same rate. Perhaps there's a difference in the nitroglycerine content or some other parameter.

[Nobade]

I wonder if anyone has tried duplexing 860 with black powder? Artillery often uses black as a kicker charge.

-Nobade

[William Yanda]

Not to hijack, but... Since a major concern with duplexing is powder migration, has anyone tried a layer of toilet tissue over the kicker charge to prevent said migration?
Bill