Reduced loads with WC860

[mto7464]

Trying to safely determine how much I can reduce a load in 7.5x55 swiss using a the lee 200 gr. boolit over wc860. Lee's book says 20% for very slow burning powders. Since there is no data for this powder 20% of what? My cases seem to hold about a max of 58 grains which is compressed. That load had poor result that I posted about. I was thinking around 45 grains or could I safely go lower?

[curator]

mto7464,

I use 35 grains in my 6.5X55 Swede mauser, so you can probably reduce your charge some without worry. I have found wc860 to burn more completely in reduced amounts when I fill the case to the bottom of the boolit with plastic shot buffer used as a filler. I also get much better accuracy with the Swede and .260 Remington converted 6.5Jap M38 using PSB and wc860.

[Buckshot]

http://www.fototime.com/D8F746F5F60AB27/standard.jpg

These target show surp WC872, but just think WC860 as in this instance they're interchangeable. These loads don't burn clean. No filler was used. It isn't an issue in the bolt action Swede, which these targets are from. However, in the pullback K31 the unburned powder could prove to be an issue.

In the 30-06 there is enough volumn of powder to generate useable velocities, and it's clean enough burning. You said you had poor results with a full caseload previously. With that 200gr boolit you mention you'll be helping to build pressure. Add in a good boolit grip in the caseneck and a crimp.

Since you're wanting to reduce the charge, I'd reduce it but substitute a solid filler back into the airspace. This will help keep pressures up and make the powder charge act like it's a full caseload. You could try COW, grits, or bran but my suggestion would be something like Super Sam. This is a ground polyethlene plastic used as a shotshell buffer. It isn't very expensive and available form most places selling shotshell reloading stuff.

............Buckshot

[Linstrum]

mto7464,

Try one load of the following recipe for effectiveness: Put in 2 grains over the flash hole of ONE of the following: IMR4227, IMR4198, IMR4895, or IMR4064. Then put in 45 grains of WC860 and then top off with Super Sam or wheat bran and insert your projectile to make a compressed load. To help understand, completely read what is below.

I get a good clean burn with WC860, WC870, and WC872 in my 7.5x54 French MAS 36 and 7.62x54R Mosin-Nagant. I would imagine that the .308 Winchester, .303 British, and 8x57JS Mauser would give similar results as well.

Here's the trick. I use projectiles that weigh in the neighborhood of 180 grains and use a lightly compressed load of powder. To get a clean burn I use right around 2 grains of IMR4227 over the flash hole that is held in place and prevented from mixing with the main charge by the compressed load. In the past I have also used IMR4198, IMR4895, and IMR4064 with indistinguishable results. Any of the fast to medium EXTRUDED STICK SINGLE BASE propellents like the IMR ones listed should give equal results, I currently use IMR4227 because 2-grains measures nicely in the little dipper I made for it out of a .22 cartridge (DON'T ASSUME THAT ANY .22 CARTRIDGE WILL DIP 2 GRAINS OF IMR4227 OR WHATEVER BOOSTER POWDER YOU ARE USING-WEIGH IT TO BE SURE!). The reason why I recommend stick-type single base powders is because I haven't done any work with double base powders to see if there are any potential pressure problems (like the "secondary explosion effect" or "SEE") from the inclusion of extra nitroglycerine into the WC powders since they already contain nitroglycerine, and the stick shape helps keep the little 2-grain booster from mixing in with the main charge and losing its effectiveness due to dilution.

When I first started trying boosted loads I used 2-grains Red Dot over the flash hole without any clean-up of unburnt powder grains or "mummies". I couldn't tell that it did anything, but 2-grains of IMR4198 was like magic, those annoying powder grain mummies were GONE!

For cartridges like the .30-06, .270, 7mm-08, 6.5 Swedish Mauser, .243 Win, 6mm Remington, all magnums, and any other cartridge with a fairly large case volume with a small projectile size, I would experiment very carefully with the WC860-WC872 powders by working them up with Hodgdon's old H870 data and then only use a 1 to 3 grains medium speed single base stick powder like IMR4227 to IMR4064 range booster over the flash hole if the loads don't burn clean on their own.

For what it is worth, using 180 grain projectiles in conjunction with WC860, WC870, H870, and WC872, those powders are too slow to get a maximum charge loaded into most of the classic MODERN high pressure milsurp cartridges like the .303 British, 7.62x54R Russian, and other .30 and .31 caliber cartridges of similar volume. But DO remember that the little 2-grain booster adds up with the rest of the main charge and don't forget to add its weight to the entire load when considering how much powder is being burned in a boosted load.

Oh yeah, I almost left out the good part. With the Lee .312" 185 grain round nose gas check boolit in my old Finn-rebuilt Mosin-Nagant 91/30 and the Lee .309 180 grain round nose gas check boolit in my "new out of the goo" French MAS 36, I get five shots all into an inch (2.5cm), more or less, at 100 yards. Of course YMMV.

[felix]

Linstrum, the reason RD did not work well is because you left no air space for the primer to shoot forth its flame. Use the baddest stick powder you can find is the best motto. Something like large cut IMR single base stuff like those you listed. Use compressible filler like the shot buffer, and don't do much compression, some yes, while seating. Let the primer do the major compression. ... felix

[Maven]

mto7464, I've used lots of WC 860 (with LR Mag. primers) in nominally .30cal. rifles and CB's heavier than 170grs., including the K-31. Unfortunately, 860 doesn't burn cleanly without some kind of alchemy or small booster charge of a faster [extruded] powder as per Linstrum's suggestion. Generally speaking, I use 48grs. WC 860 + LR Mag. primers (47gr. - 49gr. is OK) in the aforementioned rifles. In the K-31, a 200gr. CB will have to be seated deeply into the case (else it won't chamber), thereby compressing the charge. While this won't eliminate the "mummies," it will reduce them somewhat. The better way is to follow Linstrum's advice or perhaps use a small amount of cereal filler (~0.5cc - 0.7cc, via Lee Dippers)* instead. I've done this in my 8 x 57 Mau., but haven't yet tested it. Naturally I'm hoping it will improve things.


*I've been using bran (Quaker brand) since it's inexpensive and readily available. If you try it, drop the charge to 46 or 47grs. and chronograph your results.

[9.3X62AL]

You won't see me using any more fillers. Bad karma, evil ju-ju. Must genuflect........

Ah, better now. WC-860 is pretty much just Kingsford Charcoal With Attitude, hereinafter "KCWA". That said, it can be a very useful fuel--and it is inexpensive. That last might be its best attribute.

My two best outcomes are from polar opposites on the Powley Scale--the 6.5 x 55 Swede and the 45-70. The Swede with a full case of WC-860 under 140 grain j-words gave superb accuracy and 2475 FPS from its 22" barrel (Ruger 77R). Per Buckshot, this is about factory/service load performance, and I would take the loads afield without hesitation. No booster, no filler no bore trash. WLR primers.

The 45-70 does FINE work with the Lee 405 grain flatnose with 6.0 grains of IMR-4198 underneath 44.0 grains of WC-860, producing a 100% density load. Little to no bore trash, 1300 FPS (1873 ballistics, in other words), and GREAT accuracy. I shot some of these in the Burrito Shoot yesterday, and before standing up and ruining everything comprehensively I fired some sighters from the bench. 5-shotters at 50 yards usually produced 3- or 4-shot cloverleaves, with a flyer to confirm either my lack of concentration or unwillingness to scale boolits. Again, this load would go hunting in a heartbeat.

I've done some work with full cases (60.0 grains) of WC-860 in the 30-06, no booster. Lyman #311291 went 2150-2200 FPS in a 22" barrel, but some bore trash was present. I should try the 2.0 grains of 4198 to see what effect that might have on combustion--maybe accuracy might happen too. The accuracy of the unboostered loads was nothing to write home about. Some #311284 with a full case of the KCWA wasn't any more accurate, kicked significantly more than the -291's did, and left a little less bore trash. Booster is probably a good idea, and these heavier boolits weren't chrono'd.

[Linstrum]

Hi, Felix,

Nice to see you!

Thanks for your enlightenment, I had pondered the reasons why highly energetic Red Dot did NOTHING while the mild-mannered IMR4198 (and other similar ones as well) did the trick so nicely.

[felix]

Linstrum, itt was Maven who proved it by using a half grain of clays, with 860/872/etc., with enough shotgun filler to replace several grains of the slow powder. If I am not mistaken he got a 50 fps improvement as well. Something like 5010 provides enough air space where the filler would not be advantageous to use with a case full of powder. When cutting back on this kind of powder, using something simi-solid like a bran, grits, etc., filler would be sufficient to load up the case with. I would not be adverse in placing a thin sheet of toilet paper between the bran and powder, assuming the powder is large grained like 5010. Heavier compression won't hurt when using this kind of big grained powder. ... felix