I've been having some trouble mounting a Rainier Match barrel to a PSA blem upper. Initially the problem was indexing the DPMS FF tube. I finally caved yesterday and took the upper assembly to a gunsmith. In addition to the indexing problem (attributed to a receiver face that needs to be honed), he made me aware of another issue. The barrel extension receiver is out of spec (too wide) by about two hundredths of an inch. This causes the barrel to "wobble" in the receiver. This is unnoticeable with the barrel nut installed but will cause vibrations which will lead to accuracy problems and ultimately to failure. It was so out of spec, he refused to mount the barrel because he did not feel it would be safe in the long run.

The remedy, so I've been told, is to use barrel shims over and under the barrel extension, and to use a .0001 or .0002 sleeve on the extension. While this may "fix" the problem, it does not lend to consistent accuracy. It may severely hamper performance over time as the three additional moving parts wear down. So I've decided to put the PSA upper on the back burner and get another with a better reputation.

I've narrowed my new upper selection to four manufacturers. 1) BCM undersized M4 $120, 2) Seekins SP15 $125 3) Noveske M4 $120 or 4) YHM Billet $125. My first choice, based on tolerances, is the BCM, the second choice is the YHM because, well.... It looks awesome because it has flutes hogged out on the sides and will match my DPMS FF tube perfectly. btw, returning or exchanging the PSA upper is a no-go because I've had it for over 30 days. I guess this is one of the pitfalls to building a rifle piecemeal.

So help me out fellas. Of the four, which do you believe to be the best of the lot?

I'd build a rifle on any of the first three. And with a little shameless self-promotion, we have milspec uppers for $94.95. They come from the same machine shop as used by Troy and Ruger.

A blemished BCM ain't that bad either.

Not wanting to make the same mistake twice, I went with a known quantity this time.  I ordered a BCM upper, mainly because of the ultra tight tolerance of the barrel extension receiver.

 

MidwestPX, I looked at your stuff and  it does look nice, I was especially enamored by the side charging upper.  Considering a top rate upper and NiB BCG can easily cost in the low to mid 300's, it is actually a pretty good deal.  I may look into it again when I begin my 2nd build.  That upper with an ACE Skeleton stock and a Pearce 1911 grip adapter with wood slabs will make a fantastic looking AR with retro elements.