Originally Posted By: YotecallrI guess it's ok to square up a receiver, but not needed. Companies like RRA and Noveske don't and they shoot pretty well. After all you're not building a racing engine, you're just slipping in the barrel to the receiver and tightening the barrel nut. And what would the difference in accuracy amount to?
It's funny you mention those two builders. I have had them, and many other factory, custom and semi-custom uppers in my shop that simply needed squaring to make them shoot. There isn't any one manufacturer out there that consistently produces an upper that does not benefit from being squared. Most folks that receive an AR that shoots pretty well would have no idea that simply squaring the upper could make that same AR shoot much better. I have been fortunate to work with the AR platform long enough to actually see just what a "before" and "after" difference there really can be.
Accuracy is a linear function. Very un-square = poor accuracy and POI shift when changing bullet weights. A little out of square = pretty reasonable accuracy and very little POI shift. if you are lucky enough to have a great barrel, why would you settle for an upper that only shoots in the .5's and .6's when it could be in the .2's and .3's???
I have squared thousands of upper receivers over the years. Almost every one of them needed at least a little squaring, many of them, if left untouched, would have produced .750" groups with a perfect barrel, perfect ammunition and Venatic doing the shooting....
I came from a background of medical and industrial electronics. Both were VERY unforgiving when it came to mistakes or poor quality parts. If there was ever anything I could do to make a part work better or last longer, I did it. I did anything I could do to help ensure that the machine was going to run well, keep running, and I wouldn't get a phone call because of a problem. That same mindset has stayed with me in my "retirement career" of building AR's and it has served me well.
