WC867 & WC 872 what are they ??

I found these pulldown powders WC867 & WC 872 what are they equivalent to I think 872 is a slow burn right???

they are powders the military uses in 20 mike mike and 50 BMG pretty slow except for maybe the new large mags

I haunt the pull down powder venders as well, and I have heard of guys using these in .270 and .25-06 and some of the larger overbore magnums like .264 Mag, etc.

Not sure they would work and the results you would get but in something like a .338-378 Weatherby, might be a powder to try.

How do you know load data with these if they are not in the load books?

Most folks take a similar cartridge with a similar powder and load an approximate 10% less.

By reading the burn rate, and finding a powder that is close, you can load fairly good similar loads.

To be on the safe side I usually use about 80% of the load given and adjust from there.

For instance when I had my .338-378 Weatherby, I would start with a heavy .338 WM load and adjust from there.

Some guys who are a little more adventureous have just decided to toss a charge in the case, and see what happens. Not the way I would go, but it has been done.

A while go the most common method of loading wild cat rounds like 17 Bee per PO Ackley was to fill the case with 4198, scrape the excess from the case mouth and load a compressed charge.

Guys have had fairly decent success using the burn rate method by using load data for a similar powder with a close burn rate in a similar cartridge.

Within 400 yards the difference between the .338 WM, .338 Lapua, and the .338 Weatherby are so slight as to be statistically indifferent. Only the monster .338-378 Weatherby with its greater powder capacity is a bit different. But even then you are burning almost 25 gr more powder for a measly 170 - 200 fps average.

they give you load data ... and they tell you the equiv. so for example WC820 is the equiv of H110. So you start a little lower than H110 data and work up form there. The WC820 i had was just about exactly the same as H110

Thanks for your info they would probably be ok for the 7mm mag then ??

Most likely, but I would start about 10% less of the minimum recommended charge for a powder with similar burn rate.

I have an old load from THR forum in 2005 using WC 872, a 140 gr Nosler Part, and 78 gr of WC872. Cases (RP & Win) held about 79 gr of WC 872, and even a compressed load of 79.5 gr of WC872 did not show any signs of over pressure.

I used Rem 9.5 LRP, Win 210M, and CCI LR Mag primers with no apparent difference. Fouling was a little less with the CCI mag primers, but not enough to cause concern.

Extraction in my old Ruger 77 was flawless (before conversion to 7mm STW), and accuaracy was ok, about an inch at 100 yards and I could hold the 5 ring easy at 300, and rang the 300 yard gong with ease.

Not bad with a crappy barrel and the price of the WC872 was good for plinking. I usually do not load bullets lighter than 150 gr in my 7mm rifles, and save the light 7mm pills for my 7mm pistol.

Bartlett reloaders has WC872 8# jug for $48 which is hard to beat these days.

http://www.gibrass.com/gunpowder.html