WC872 & 338 WM

[BABore]

I have some 338 WM cast bullet data, from Accurate Arms, using their 8700 powder. I'm thinking of trying some WC872 for this. Accurate sent me data for a 225 fr FNGC that is between 2,000 and 2,500 fps. Has anyone compared the two powders? I also see that WC860 is listed as using H870 or AA8700 data. Between WC860 and WC872, which is closer to 8700?

[waksupi]

You can't put enough of either WC860, or WC872, into the .338 Win Mag case to create excess pressure.

[BABore]

I realize that. The same could apply to water. :-)

What I am asking is "does WC872 have similar properties to AA8700". I know that they are both ball powders and have similar suggested burn rates. I'm pondering if I should try out a pound of canister AA8700 at $20, or go with 8 pounds of WC872 at $60. Never used surplus powder before.

[Ricochet]

Similar, yes. Identical, no. Your results will vary depending on the lot of powder you have. I've scratched my head about the same thing. Looking at load data in manuals that have both in them, in the .300 Weatherby Magnum (my cartridge of interest when I was doing this) AA8700 gave lower velocities than H870 with similar charges. I've got both WC860 and WC872 from pulldown batches, and my WC860 gives a bit higher velocity than H870's numbers from the books. I haven't tried my WC872 yet, it's in reserve for when my WC860 runs out (I'll be very old and feeble by then.) Both Hodgdon and Accurate have histories of selling surplus powders, and AA8700's bound to be a surplus powder similar to the above.

I've had (but can't find at the moment) a copy of a data sheet listing the nominal characteristics of a whole bunch of Olin Ball Powders. The relative burning rates of WC860, WC870 (H870) and WC872 were 82, 81 and 80, respectively. That's close enough that their relative burn rates could change order from lot to lot and from load to load with the same lots. I've seen reports of AA8700 burning faster than H870, contrary to the loading manual data I've looked at, and of WC860 burning more slowly than WC872. None of this stuff is carved in stone, obviously.

There's another 20mm powder on that table I have, WC875, that's somewhat slower than WC872. I don't recall the exact relative burn rate number. Wish I could find that table!

[Ricochet]

I'm pondering if I should try out a pound of canister AA8700 at $20, or go with 8 pounds of WC872 at $60.
Um, for me that question was a no-brainer. That's why I have "several" pounds of WC860 and WC872. As I alluded to above, H870 was a Hodgdon-purchased and remarketed surplus batch of the long obsolete WC870 20mm powder, replaced by WC872. I have speculated (but have no solid information) that AA8700 might be surplus WC872. The question is, whether you feel the need to have published data of a tested lot of powder. As was stated above, it's pretty much impossible to overload the .338 Win Mag with any of these powders, and you can easily develop your own loads, using the published data to give a starting point. If you've got a Chrony you can know your muzzle velocities (which you may find differ quite a bit from the published data in your rifle with the published recipe, anyway), and methods of observing for unsafe pressures are widely published in loading manuals and elsewhere, online and in print. It's really pretty hard to be a cast bullet shooter and stick with only published recipes anyway, IMO, and although you're unlikely to fall into danger using such loads you may find that your results differ from those of the load developers.

[Buckshot]

Ricochet, ".................The relative burning rates of WC860, WC870 (H870) and WC872 were 82, 81 and 80, respectively. That's close enough that their relative burn rates could change order from lot to lot and from load to load with the same lots."

Exactly. My WC872 is 50 fps faster load for load then my WC860.

BABore, "I'm pondering if I should try out a pound of canister AA8700 at $20, or go with 8 pounds of WC872 at $60. Never used surplus powder before."

Well, the one pound can of AA8700 would be the cheaper way to go if all you were wanitng was to load a few. I would opt for the surplus. It may not deliver the very last FPS or lb/ft of energy, but it would be useable in that cartridge for sure. You're getting 8 times the powder for only 3 times the money.

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

[Char-Gar]

I will leave all of the science stuff to the guys whose brains work that way.

I bought 32 pounds of WC872 and have been very pleased with it. It is the best stuff I have used for cast loads in the 1.8K fps and up loads. The accuracy it produces in the 30-40 and .308 cases is outstanding. I use it in the 30-06, but place about .5 to 1 cc (depending of the weight of the bullet) of PSB on top of the 50/WC872 to give a lightly compressed load. I have tried this in 4 30-06 rifles with six different bullets and this load will give all the accuracy the rifle and bullet have to give.

With scaled 165 RCBS SIL bullet, this load will give 1.5 - 1.75 MOA ten shot groups out of my stock 03A3 all day long. That is about all one can expect or hope for from a rack grade full military 03A3.

I use this powder in the 45-70 and the 30-30 but in both of these round it takes a kicker charge of 3031 to get a good burn.

In my book WC872 is a primo cast bullet powder