Upgraded upper reciever really matter

[waccamawscout]

Building a new target rig and looking for uppers I run across precision firearms thick wall side charge upper with match carrier. Does it really benefit me any in accuracy or anything for that matter over a ordinary mil spec. Appreciate any advice on the matter.

[grayfox]

Haven't used that thick wall upper. But as for mil spec, there's spec and then there's spec.
Now for side chargers, there may be some differences, I've used only standard semi-auto's.

My recommendation would be to get an upper from a good mfr, and where you have some confidence that
a) the front is square or lappable (if you want to take the time), and
b) good fit and function with the lower you will use.

Some of mine have been "mil spec" but lower cost... and they're a bit looser than a good one like BCM. Every place that rattles or is loose "just a bit" will affect your overall accuracy. "Moveability" is not your friend here.
From here out I plan to use better to good ones, BCM, maybe Aero, .... a spike's I used turned out pretty good.
The difference is maybe $50 from a budget one but shootability... you'll use up more in ammo than that $50 trying to find your good loads.

[longbow62]

I am using a VLTOR MUR upper for my build. It is advertised to be thicker walled and tighter internal tolerances for both added strength and accuracy. That being said I might also add in my opinion the barrel is the most important accuracy component. So unless a primo barrel is used the stiffer upper receiver is moot.