223 can be shot in the 5.56 nato rilfes - so no issue
55 grain is a bit light - but should be good out to 100 yards without too much issues.
What type barrel is it? Standard 5.56 nato, 223, or Wylde chambered? Wylde is designed to be in between the 5.56 and .223 and will shoot both.
I think you should have good luck between 50 grain - upper 70's with a 1/7 twist rate. For lighter bullets I would try to limit your range to 100yards or less.
You could always look at the bulk ammo folks (support your sponsors) - depends on the intended use.
For indoor range I have to make sure I get the plain old jacketed rounds.
If you want to go cheap - you might have some luck shooting non-re loadable wolf ammo. I am not fond of some of the stories I have heard from Tula. Some match grade AR-15 can be picky and have issues ejecting this type of round.
1) get a broken case extractor
2) get a extra extractor
3) buy a small box and run it thru your rifle before going large order.
Cheap ammo - worth looking at - but steal cases can be hard on the receiver. http://www.bulkammo.com/bulk-223-ammo-223rem62hptulablack-1000http://www.aimsurplus.com/product.aspx?item=ABS223HP62&name=Silver+Bear+.223+62grn+HP+20rd+Box&groupid=156
Over the last few months I think I have seen the price bottom out a bit and climb up in some places.
The ammo you referenced seems to be good, most of the reviews are ok.