Have come into several pounds of 870 which is discontinued. I also see its touted as a good powder for the 264 mag which I don't have. Is it any good for the 7mm and 338 magnums or with any non-magnum calibers?

You may get some good out of it in the 7 Rem mag with heavy bullets, but I wouldn't waste any time on it with the 338 Win magnum. They're similar sized cases of course, but the driving factor is the relation of bore size to case capacity.

Are you talking about AA8700? There's also H870 (discontinued as well) and WC870 (mil surplus 20 mm stuff if I recall correctl) in that realm of burn rate.

Agree with mathman on the usage. Pretty good following of folks who use it in the 7mm RM pushing 160s and above.

I believe you mean WC872. I have WC872 and mine is slower than H870

The WC872 that I have is so slow that to get enough in the 300 RUM to work with 180 & 200 grain bullet require vibration and heavy compression

I've shot a lot of WC860 and it's close siblings. Save it for the Ultra mags and the 7mm STW.

nope...the white 8 lb jugs I have with the orange sticker say WC870 Lot# 46383. I believe it's in the similar burn rate regime as WC872.

While I currently use H1000 in my 7RM, a prior load was 80 grs of WC870 behind 160s which had me just shy of 3,000 fps.

**** I believe the below is pulled from surpluspowder.com

WC860 Original application is U.S. .50 Cal. BMG ammo, used for the Ball
M33 and API M8 projectile. A ball powder which can be loaded using
Hodgdon H870 or AA8700 data. Just received a limited supply.
This is pulldown ball powder from Lake City.
$48/8# jug; $176/4-8# jugs ($44/jug); $240/6-8# jugs ($40/jug)

WC870 Here is some of the exact original type powder as was sold by Hodgdon, called
H870, until discontinued. A ball powder originally used in the 20mm Vulcan
round, until replaced by WC872. This powder is also very similar to Accurate
Arms AA8700. Because of the lot to lot variations in burn rate, be sure to
begin with listed starting load data. Works great in the .50BMG and other
large capacity magnums.
This is pulldown ball powder.
$48/8# jug; $176/4-8# jugs ($44/jug); $240/6-8# jugs ($40/jug)

WC872 Original application is U.S. 20mm Vulcan ammo. A ball powder which
can be loaded using Hodgdon H870 or AA8700 data. Very limited supply.
Ideal for .50 BMG and other large capacity magnums.
An unexpected acquisition.
This is pulldown ball powder.
$48/8# jug; $176/4-8# jugs ($44/jug); $240/6-8# jugs ($40/jug)

I've got some 860 too. Glacier slow stuff.

I have used a lot of h870 in the 25-06, 264 wmag, and 7mm rem mag. Fed 215's are a must. It does it's best with heavy for caliber bullets. It's not the cleanest powder either. Just Google it there's data out there. When I'm done with my h870 I have an 8lb of thunderbird t5050 which uses h870 data...
Mb