WC 820 versus W296

[luzyfuerza]

I scored an inexpensive 8 pound jug of WC 820 a couple of months ago. The label says that it is similar to H110 (and presumably, W296), but of course, that doesn't mean that it is IDENTICAL to H110/W296 and that I can blindly use H110/W296 load data.

To figure out how my batch of WC 820 behaves, I put together some 300 blackout and 30 carbine rounds using identical cases, bullets, primers, trim lengths, OALs, etc. I loaded half of these cartridges using WC 820 and half using W296.

Here's the data:

300 Blackout

Brass was formed from Lake City .223 cases, 147 grain pulled projectiles, and Wolf .223 SR primers. Case length and OAL were consistent from case to case. Gun is generic 300 blackout upper on a stock Bushmaster lower.

15.0 grains of W296 produced 1722 fps, SD=9
15.0 grains of my WC 820 produced 1795 fps, SD=30

15.8 grains of W296 produced 1829 fps, SD=34
15.8 grains of my WC 820 produced 1915 fps, SD=9


30 Carbine

Once-fired Privi Partisan cases, Remington 110 grain JRNSP bullets, and Wolf SR primers. Case length and OAL were consistent from case to case. Gun is a WWII IBM M1 Carbine.

14.5 grains of W296 produced 1870 fps, SD=15
14.5 grains of my WC 820 produced 2017 fps, SD=10




Clearly, my batch of WC 820 produces higher velocity than an equivalent weight of powder from my canister of W296. That's good information, but it doesn't get me all the way to where I want to be. Three questions:

1) For those of you who have successfully used military surplus powders, how did you establish loads that you felt were safe for your guns?

2) For those of you who have used WC 820, did your batches of WC 820produce higher or lower velocities than the comparable canister powder? Is there a canister powder that you found was a closer match for your WC 820?

3) I have assembled some test loads in .41 magnum using WC 820 and W296but I haven't shot them yet. In your experience, is there anything you'd expect to be different in a magnum handgun round versus the rifle rounds I've looked at so far?



(Other factoids: all W296 charge weights are less than maximum. No fired cases showed any signs of overpressure. Both rifles functioned well with each load. My WC 820 looks very different than my W296 (color, grain size, etc.).)

 

[ArchAngelCD]

It seems your batch of WC820 is somewhat faster than the W296 you have on hand.

When working up loads with surplus powder I will usually start with the starting charge weight of the commercial powder it's supposed to mimic. I will then increase in small increments until I reach the velocity of a safe load using the commercial powder.

IMO your 30 Carbine load is probably over the SAAMI pressure limits judging by the substantial increase in velocity over the W296 load. I would drop the WC820 powder charges back until the charge you use generates a similar velocity as the W296 load.

NOTE: Every lot of WC820 and all surplus powders can and will be very different so you have to do the same workup each and every time you buy a new lot of powder.

 

[41 Mag]

Ditto to all of what ArchAngelCD said above.

I use a similar powder which was sold as WC-297. It is supposedly the commercial version of WW-296. I did exactly as noted above when I worked up my loads. My lot is about 1-2 grains slower than my canister grade 296. It depends on what size case it is going into, or what bullets I use, as to how well it gets lit up. The bigger the case, or the heavier the bullet the faster it gets. None the less as mentioned above, I simply use the velocities I have gotten with the canister grade loads to keep things in check.

There is quite a bit of data over on Castboolits in many different calibers using 820. It would be a good place to check out how to proceed with it.