What is this powder used in {caliber } Thanks

It's a super slow powder with big (hard to meter)grains. It shoots great (and is usually cheap) in overbore calibers like the 7stw, 30-378, etc. go to hodgdon's website and you will find some loads for it but not alot. What do you want to shoot it in?? (Should have paid about $13/lb for it or less.) LAst gun I experimented with it in was 300 wby. A full case did about 2800 fps with a 180 grain so I "duped" 30-06 loads. It actually shot pretty good. Muzzle blast is quite horrendous--try not to start a forest fire.!!

If your question is, "What was it originally used in?", the answer is .50 BMG. It works well in most magnum cartridges with heavy bullets. Too slow for the highest velocities with medium weight bullets. In the recent crop of huge Ultra Mag-type cartridges they work for maximum loads with lighter bullets and can be overloaded, which is hard to do with the older magnums.

I use a lot of 5010's Western Ball powder sister that was used in .50 BMG at the same nominal loads for the same velocities, WC860. I use it in .300 Weatherby Magnum and 7mm Remington Magnum. When that runs out I'll start using the similar WC872 that was originally used in ammo for the Air Force's 20mm Vulcan cannon. I've already got some stashed away safely. (H870 was originally WC870, another similar 20mm Ball powder.)

Some cast bullet shooters like to use full case loads of these very slow-burning powders in medium size cartridges like the 6.5x55mm Swedish Mauser, 30-06, etc. They give modest velocities with often very good ballistic uniformity, and act something like a smaller charge of powder with a filler, the filler in this case being powder that doesn't finish burning. Pressures are very modest in these loads.

THanks for the info

I've tried it in an overbore wildcat (6.5-300 Wby) and it's burn rate was similar to H870 in the same rifle, although it's supposed to be slower. They ARE big granules!

Hitech has it for closer to $3 a lb. I stuffed a bunch in my 470NE and got a pleasant 1600fps.

I would agree that 5010 is very close to H-870 (and H-570), although it seemingly may not contain as much energy per grain. It is faster (at least in the lots that I have tried) than WC-860 and WC-872. If you use 5010, be prepared to weigh each charge. There's no way it will meter with any reasonable accuracy. It's like putting gravel in your powder measure. It's also trying of your patientence to get it through the neck of a powder funnel into something like a .264 Winchester!