surplus 872 question

[nekshot]

I have some reload data from others that say they get 63 gr in a 7mm mauser cartridge with a 175 gr jacket bullet. I cannot get close to that with mine. I have 872 lot#49610 and all I can get in is 55gr and still hope to seat bullet. Has this powder changed this much over time or is there a trick at getting more powder in a given cartridge that I don't know? And for the wondering souls, I don't mind dirty barrels from this powder!

[Yodogsandman]

7mm magnum load? Just my WAG...

[nekshot]

I thought too they might have meant another cartridge but my 7 mm Rem mag takes 80 some grains.

[wiljen]

I think it is a misprint. I have never seen the 7mm Mauser hold 63gr of any rifle powder. I'm thinking maybe W231 or AA9 could fit 63 gr since they are basically dust but neither would be a smart thing to do as that load would surely cause spontaneous disassembly of your rifle.

[Freightman]

I get 63 gr of WC872 in a 30-06 case not a 7mm Mauser.

[giddy]

The military has sourced "WC" type (double-based, spherical) propellants from at least 2 manufacturing plants (Badger and St. Marks, come to mind). Manufacturing procedures could have varied, which affects the burning rates and densities of each lot number. This is why it is so important to work up loads whenever using a different lot number of military powders. None the less, I can't imagine a 7x57mm Mauser case holding 63gr of any type of powder. Maybe in a 7mm-06 or 280 Rem, but not a 7mm Mauser.

[Bjornb]

A 7mm Mauser case takes 55 grains WC872, loaded to bullet base with .3" seating depth. I shoot it all the time in the 30XCB (7mm Mauser necked up to 30 cal). Gives me 2150fps with a 160 grain cast bullet. Almost identical speed to the WC860.

[Cary Gunn]

Bjornb,

I'm interested in the particulars of your 55-grain WC872/160-grain cast 30XCB load.

How clean is the "powder burn," and what is the barrel length giving you the 2150 fps?

Also, what primer (brand, standard or magnum, etc.) are you using to touch-off the load?

If the load doesn't burn cleanly, is it leaving much unburned powder in the bore? If so, how are you dealing with the residue in the bore and/or chamber?

I've found that I often have to take extraordinary measures with WC872 to get a clean burn in bottle-necked military rifle calibers, even when using very "heavy-for-caliber" bullet weights.

Without the clean burn, I get accumulations of unburned powder in the bore and chamber, sometimes resulting in a fired case being heavily marked and indented from firing in a chamber fouled with unburned powder granules. It's hard on brass, and doesn't help case extraction even a little bit.

I've gotten some relief by switching to Winchester LR caps, which seem to be "friendlier" than other brands to ball-powder ignition. In attempts to gain better ignition -- in less-than-100%-density loads -- I've also used compressed charges topped with granular plastic fillers, and I've had some success with compressed "duplex" loadings using very small "kicker" charges of moderately fast pistol or shotgun powder next to the flash hole, followed by compressed loads of just WC872 or a combination of WC872 topped with the granulated plastic shotshell buffer material.

I don't recommend the "duplex kicker" loads to anyone else, and I'd rather not use them myself if i could find any other means of avoiding it and still get a clean powder-burn in mid-sized bottle-necked rifle cases with the very cheap, ultra-slow burning surplus "20mm cannon" ball powder.

Thus, I'd sure interested in an elaboration of your findings with WC872 in the 30XCB.

Thanks and happy trails,

-- Cary Gunn --

[Bjornb]

I loaded up some rounds today and took them to the range. The cartridge was the 30x57 (XCB) primed with CCI 200s (W-W cases), load was a full case WC872 (55 grains), and the bullet was the NOE 165 XCB, cast from monotype, sized to .310 and lubed with White Label 2700+.

The rifle was a Goodsteel-built target rifle ("Felix"), a heavy Mauser 98-based single shot with a 30" Brux barrel in 1:14 twist.

After shooting 10 rounds for barrel conditioning I fired these 15 for the record, speed was measured by a Lab Radar Doppler chronograph.

I checked the barrel periodically for unburnt powder, but there was never much of a buildup and no powder appeared to have worked its way into the chamber or lug recesses.



Not stellar accuracy, but not bad either for old cannon powder. Velocity was a little higher than I had expected.

[Freightman]

WC872 and WC860 are my accuracy loads on my S-S CVA 7mm 08 seems like 54-54 gr will go if memory serves me right . Plus it is available and some of the other rifle powders are not, and cheap.