Junk, stay away, it's not worth risking your pistol!
Ultramax quality control, or lack thereof, this is the kind of thing that blows up guns:
Ammunition Review & Reference, listed by order of quality as determined by user reports, note Ultramax is near the bottom of the quality barrel, this is for 223 ammo, but the quality control relates to the brand in general:
http://www.ar15.com/content/page.html?id=210
Ultramax quality control, or lack thereof, this is the kind of thing that blows up guns:

Ammunition Review & Reference, listed by order of quality as determined by user reports, note Ultramax is near the bottom of the quality barrel, this is for 223 ammo, but the quality control relates to the brand in general:
http://www.ar15.com/content/page.html?id=210