WC 860 in my SKS with a ~162gr. C.E. Harris designed CB

[Maven]

In this time of powder scarcity, and wanting to test my "as issued" Type 56 SKS with something other than RL-7 (which I have very little of), I thought about trying an "inappropriate" propellant. My thoughts turned to WC 860, which I have quite a lot of. Slower propellants such as IMR 7383 + LR magnum primers work OK in my SKS with the ~162gr. Harris designed CB (accurate, extract more gently than RL-7), so I thought I'd give WC 860 a test drive today. Using a fired 7.62 x 39mm case whose neck I partially removed, I was able to determine how much of 860 would fill the case with a bit of compression: 22grs. will, but 23.6grs. are better. I set my Lee Perfect Powder Measure to throw that amount (after much weighing of course) and came up with 23.5gr. - 23.8gr. WC 860 + WLR magnum primers. Once I charged the cases (2x fired + annealed), I seated the CB's a tad deeper than usual, i.e. 2.1" v. 2.125", so I could crimp those CB's in the proper place: I was hoping for a cleaner burn by crimping them. Btw, the bore of my SKS is on the large side so my CB's are sized to .316". The mould is from NOE and casts nicely.

Results: As you can see from the attached target, my load hit low, but I was able to change the sight picture a bit to get higher hits @ 50 yd. The 23.5 - 23.8gr. load was accurate enough even with a crimp, but wouldn't eject the cases. In fact, it sounded almost like a suppressed rifle. Surprisingly enough, it wasn't very dirty and there was nary a trace of leading with the GC'd CB's swished around in Lar's Liquid Xlox. Although I'd like to increase this load to 24.0gr 860with a booster charge of some sort, but I'm not certain which of these would be the better choice: 3gr. Hodgdon's Clays or 3gr. FFFFg (smallest Lee dipper for either)? What say ye?

 

[Spindrift]

I say success!
Thanks for the report. I can’t offer any opinions on neither the powder (no US surplus powders in Norway) or booster charges (never tried), however. Good luck, Maven!

 

[Maven]

Thank you Spin....! WC 860 is a very slow surplus ball powder originally used in the .50cal BMG I think. The only reason we even considered using it back in the day was that it was inexpensive. Perhaps a false economy since there was often quite a bit of it left behind in the bbl. and just fired cartridge. As an example, I used to use 48gr. WC 860 with 175gr. - 200gr. CB's in my .30-06 and got good accuracy, but unburned powder (and heavy recoil!). By way of comparison, I use only 21- 23gr. IMR 4198 with those same CB's and get excellent accuracy and clean burning without having to use magnum primers.

 

[CZ93X62]

Maven--

Buckshot and I have in the past done a whole lot of experimentation and lead-launching with WC-860, though I don't recall any work involving the 7.62 x 39.

I'll say this--if your shots are not leaving zombie powder granules after firing, you are doing something right. Heavy-for diameter bullets are a big plus with this slow-burning fuel, as are relatively small bore volume/large case capacity ratios. The 6.5 x 55 Swede with 140 grain J-words atop 100% density loads of WC-860 gave 1896-spec velocities (2400-2450 FPS) in both Rick's milsurps and my commersh Ruger 77R, as well as SUPERB accuracy. In 30-06, a 200 grain Lee bullet gets almost 2100 FPS in my Husq. Mauser 98, and threatens 1.25" at 100 yards. 1.5" easy.

I have duplexed 860 in the 45/70, my rifle's ideal load was the Lee 405 grainer atop 6.0 grains of IMR 4198 followed by 48.0 grains of 860, lightly compressed to keep the layers unmixed and lit by Fed #215 LRM primers. 1300 FPS and accurate. Buckshot wants no part of duplexing. He really needs to get out more.

 

[Ian]

Allen nailed it: Use 4198 as your kicker. Start at about 2 grains and keep your + 100% density always and adjust proportions. Work up abhalf grain at a time, you will know when to stop adding kicker. A standard primer will do if you have them. I haven't done it in the x39 or with mag primers but have duplexed in the 30-30 with some of Graf's 20mm surplus. I started with Blue Dot on my own but got better advice, and IMR 4198 it was. You will get to the point at probably 4-6 grains that the mix begins to behave like ww760 or even 4895 as you add more.

 

[Joshua]

Not to drift to far from the topic. Have any of you used IMR 5010? There are a few jugs getting auctioned off at a local auction house.

For a few years now I’ve been reading about all of your exploits with these surplus powders. I might try to pick up those 8 pounders if the bidding doesn’t go all crazy.

 

[CZ93X62]

IMR 5010 is the Dupont/IMR stick propellant for the 50 BMG. WC-860 is the spherical propellant created for the same niche. I have no experience with 5010.

The WC-860's principal attraction was its very low price in the 1990s--as little as $2.50/lb for a few years from GI Brass. At $2.50 to $3.50 per pound, the amounts needed to get good results were affordable and fun, and the boomy report just adds more joy to the exercise. I saw some "new" "860" in Hodgdon flasks a couple months back at the local toy emporium, and they wanted just slightly less per pound than they did for H-335. Fuggetabouit.

 

[Maven]

Joshua, I managed to use at least 8lb. of IMR 5010 when an 8lb. jug could be had for little $$. It was best (a relative term) in my .30-06 and 8mm Mauser. with heavier CB's, LR mag. primers, and, get this, powdered bran or spherical shot buffer. Naturally, with a filler you had to adjust the charge downward somewhat, but the filler worked to increase efficiency + you didn't need much "filling." As little as 0.3cc in the 8mm and 1cc in the '06 were good for me. (I used Lee dippers for this). Lastly, most powder measures won't reliably throw charges of that big, chunky powder, but a dipper of some sort, e.g., the Lee set, works really well.

 

[Maven]

I just returned from the range after a second test of the WC 860 load, this time with a booster charge. As I didn't have any IMR 4198 on hand, I thought RL-7 would be the next best thing. After making a dipper out of a new .22L case (I first neutralized the primer), I found that it would throw ~4gr. RL-7, I then used it to charge the cases. Since I didn't know how much pressure the booster would generate, I dropped the 860 load to 20gr. All else was as my first post, except I used a bigger target spot.

Results: Perhaps a bit tighter than the first group in post #1 + 8 out of 16 ejected, but there was still some unburned powder in the bbl., magazine well (That's where it goes with the SKS), and in the action: All of that was easily removed. (Btw, a bore snake is a great tool for a quick bbl. clean-up at the range.) Lastly, there was no leading at all, but I think I'm fortunate as this particular SKS has never leaded the bore (unlike my first one!). I'll post a photo of today's target shortly, i.e., when my photo program stops acting up.

 

[Ian]

Well, it didn't blow up, so that's a good start

A chronograph really helps see what's happening.

 

[Maven]

Thanks, Ian! Actually I do have a 20 yr. old Shooting Chrony, but it's rather a pain to set up. I think it still works though.

All, in the photo in post #9, today's results are not highlighted with the black marker. They're also a tad higher on the target with a central aiming point.

 

[CZ93X62]

WC-860/867/872 have all been called "Fillers with Attitude", owing to their low pressures when run in cartridges not intended for such slow fuels.

Buckshot and I had success & accuracy in 6.5 x 55 and 30-06, and with the 100% density loadings there were few if any powder zombies. Fed #215 primers were used, which are reputed to be the hottest generally available. (Even in fat times, Fed and Rem primers are a PITA to find around here, I think mine came from Miwall at the Big Reno Shows).

It's not all beer and skittles, though--these slow fuels leave quite a bit of powder fouling behind. If you are using conventional lubes like 50/50 or Carnauba Red, the fouling stays soft, but with jacketed bullets the fouling gets crusty and hard. At about 15-20 shots, accuracy starts to fall off with the J-words, so it is time to mine your carbon after 10 shots. No huge deal, a couple patches soaked in Hoppe's melts it right out just like hot water does to black powder fouling. Brushing gets a bit more, but just the solvent and a couple dry patches will restore accuracy during a range day.

One epic fail--a 100%-density load in 223 bolters did not shoot worth beans for me, jacketed or cast. Lyman #225438 and RCBS #22-55-SP (which do good work with 2400 and 4198 in the 1700-1800 FPS range) "Went shotgun" immediately, Sierra 55--60--and 69 grain bullets were slow (1400-1600 FPS), inaccurate, and left LOTS of powder zombies after each shot. Total mess. CCI 450 primers were used, and didn't matter a bit.

 

[Maven]

Allan, I too tried it in small caliber bottle necked cases, the .243Win. and 6.5 x 55mm Swede (with CB's of course!) and got an unholy mess. OTOH, it works quite well in my .30-06 and 8 x 57mm, again with CB's. Heavier ones do better and improve WC 860's efficiency, but there's always a bit left behind.

 

[CZ93X62]

I saw your charge weights in 6.5 x 55, and that accuracy was lacking. I used 100%-density in my R-P Swede cases, 55.0 grains, just as Buckshot did. I STILL use this recipe in 6.5 x 55, 140 grain j-words of any make. LIGHTS-OUT.

I haven't tried it in 243, jacketed or cast.

 

[Maven]

Success at last with WC 860 and the ~160gr. C.E. Harris CB in my SKS! This time I use measured charges of both the "kicker" and main charge: 4gr. RL-7 + 21gr. WC 860, with WLR mag. primers. I seated the CB's a tad deeper than normal, 2.11" v. 2.125" so I could crimp them (Lee FCD) for a better burn. Accuracy was what I've come to expect from this particular SKS and ejection was 100% and fairly gentle. Tomorrow I'll try to post a photo of the target.

 

[STIHL]

Very nice shooting. And I would say a success in your efforts.

 

[Ian]

I'd be tempted to push the booster ratio a little more to see what happens in order to have a better idea of where the middle is, but I think you accomplished your original mission.

 

[Maven]

Ian, With the booster, charge, and seating depth I used, there's not more room in the boiler room. I'm compressing the 860 as it is and that's not the best thing to do with ball propellants. While I have a photo of the target, my photo program is a bit finicky just now so I'll try to post it later or tomorrow. Meanwhile, here's a photo of the Harris CB (on the right) along with a Lee 175gr. 8 x 57mm CB, which I've tried in the SKS (after heavily resizing it). If you can stand the radical resizing effort, it is worth it as it is quite accurate.

 

[Ian]

Ian, With the booster, charge, and seating depth I used, there's not more room in the boiler room. I'm compressing the 860 as it is and that's not the best thing to do with ball propellants

I don't think you're quite understanding what I meant workup is with booster. Add booster and take away main charge but keep overall density the same as the previously tested load.

You have to start and remain at at least 100% density, very slight compression is better, because you don't want the booster migrating around through the main charge when handling the cartridges. If 100% density at safe main charge levels means you can't fill the case, then you have to add a little filler to keep the powder column intact (with considerations for how much the full density plus effects of filler add to peak chamber pressure). In the tiny x39 case and the powder you chose, you do not need buffer so that simplifies things. You have a compressed load at 21 grains/4 grains. The next step is something like 20.5 grains/4.5 grains and so on with considerations for density differences between the two powders. Main thing is increase the booster a specific amount in increments and make up the powder column to slight compression with the main charge, whatever that main charge weight ends up being to achieve the same overall density of your previously tested load.

 

[Maven]

Got it!

Btw, Here's yesterday's target, with those results marked in red (note: there's 1 hit @ 6 o'clock 1" from the bottom of the paper and another @ 5:30 in the black)