Need some advice. Maybe some of you own this setup or not, I would like some advice as to what the best range/plinking and or match grade ammo would be for this specific rifle based on these specs. Price is a non issue and I would like to slowly store some away of course.

The rifle is a POF. The minuteman is the model. I believe its a Cabelas exclusive, but is very similar spec wise to the Puritan they produce.
- 16.5" nitride heat treated barrel
- 1:8, 1/2-28 barrel threads
- A2 flash hider
- E2 chamber
-  Nickel plated 8620, integral keyed, steel bolt carrier (billet machined), heat treated/plated per MIL-SPEC.
- Roller cam pin, NP3™ coated.
- Chrome plated bolt, heat-treated to MIL-SPEC.

And of course its a short stroke piston system. Just need some advice as I'm new to 556/223. I would prefer to shoot just one caliber and am leaning heavily toward .556.

Edit: I will be using solely gen 3 pmags. I just purchased and do not even have iron sights yet, so its not been shot just cleaned admired and taken apart a few tons o times

Not real sure about what you have there.

Never heard of an E2 chamber or chrome plated bolt, per mil-spec.

I'll assume, though you shouldn't, that it's a 5.56 chamber. You need to confirm that.

That said there's no reason to limit yourself to only 5.56 loads. You need to try out a variety of .223 and 5.56 to see what your rifle prefers. Every rifle is different. Find out what yours shoots best and stock up on that.

M855 isn't know for it's accuracy, generally speaking. M193 might give you better results. But there are undoubtedly .223 loads that will give you the best accuracy.