My experiences with "Canned Heat" (Georgia Arms) FMJ has been very positive - very consistent and accurate (if I do my part.) I may also consider reloading in the future.
I have no experience with Federal or Sellier & Bellot FMJ.
Remington JSP ammo is also very good, but I'd use it for "serious social purposes" only (too expensive for plinking, unless you're Bill Gates.) Just run enough through your carbine to ensure it feeds properly, as some guns may not like non-FMJ ammo.
Whatever you do,
AVOID "American Ammunition" (headstamp "A-MERC") ammo - don't be lured by the siren song of low prices, it's cheap because it sucks - numerous duds and ruptured cases.
See this thread:
http://www.ambackforum.com/viewtopic.php?t=9161
Hope this helps.