meh. You can do a heck of a lot better than 5" from a bench at 100 yds, but its not the ammo. You can get 1.5" or better with cheap American eagle 55gr boat tail, the cheapest brass cased stuff available (now about .25/round with rebate). Your barrel, rail, trigger (and you!) matter most. My rifle can get 90% of shots within a 3" ring at 200 yds with AE 223. The max spread on my last 9 shot group with AE 223 at 200yds was 4.2." If you have a good set up (i.e. match grade barrel, and nice trigger) and half decent technique (my technique is only half decent I can assure you), you ought to be able to do way better even with cheap ammo. I once had a guy shoot one hole groups at 100 yds with one of my rifles with cheap steel case ammo, proving to me it was me and not the rifle or the ammo.
I am glad I saw this thread, I was about to pick up some cheap Frontier. Now, not so much.
It depends on the gun still. My precision AR turns in 1MOA or a little better depending on the match ammo. It does not like 55gr ball. The best I can manage is 2MOA with 55gr ball and Federal runs like crap out of it. The best 10 shot group I have ever managed was 2.5MOA with .223. XM193 and worse, XM855 tend to be more like 3-3.5MOA 10 shot groups out of it.
IMI does the best with about 1.8MOA for M193 (about the same for their .223 55gr FMJ) and their M855 is typically 1.2MOA 10 shot groups, but I get the occasional flier out of it that will push it closer to 2MOA, but I only typically get about 1 in 10-15 fliers. PPU69gr, Gold Dot 64gr and a couple of other loadings will get down to about .9MOA 10 shot groups.
That is a sample size of 1 gun though. My 16" has only ever had a red dot on it and it has a new barrel. So maybe it will do better than my 20" will with federal (fingers crossed).