I just bought an ar and part of the package was 750 rounds of this ammo.  I don't know what it is,  maybe you guys can help.

It is called "HSM" ammunition out of Missoula, MT.

The cases read "LC"  "99" and there is a little circle with a cross in the middle.  

The stuff looks like it is reloaded but I can't tell for sure.

Also,  it is bright orange boxes that read "Police Ammunition" in big black letters.

What is this stuff?

That's the ammo sold by The Hunting Shack. It sounds like the ammo is remanufactured using once fired Lake City brass. I am not sure what type of load you have (FMJ, JSP, JHP, Match) but it is likely pretty good ammo. Most people who have used HSM have generally liked it. But again, it depends on what combination of bullet/velocity it has as to what role it will be best suited to.

-CH

HSM has a good reputation. Lot's of LE agencies use their reloads for training.

Thanks for the replies guys,  I will shoot some and let you know the results.