Colt m16A2 upper build

[ssgross]

They have guys at Fulton to do a straightening job and then blow it out at a sale price.

Haven't seen those ever at Fulton. Full price was full price, and then some as it already had a front sight post pinned.
I certainly did my due diligence to make sure it wasn't me or my receiver before sending it back. Here is how I troubleshot...

1) I happened to have a colt factory a4 barrel assembly handy on another rifle. Put that one on this here a2 upper, and alignment was spot on. hmm.

2) next likely cause would be the front sight base installed off to the side. To check this, install the barrel, and tie a knot in a fishing line. Pass it through the peep, then tie a weight (a few washers) to the other end, stretch it over the post and down across the crown. Looked pretty dead on...and I'm confident the tolerance on this method is within 0.002 or likely a lot less after I used it align several new krag front sight bases - which all zeroed at dead on mechanical. A little math shows 1 MOA is ~0.00573 of the front sight post on the m16a2. The problem wasn't the front sight post alignment.

3) so...bent barrel? I'd like to think not. I suppose the bore could be off kilter too, but from the quality of the garand, springfield, and krag barrels I've fitted from criterion this shouldn't be the case. Don't have a cylinder for the drop test, and no lathe to for the bore axis test (Jim you are always great at reminding me I want a lathe ). My guess is that "Criterion by Fulton Armory" as these are marketed means a blank from criterion that FA finishes the contour on, installs the barrel sleeve and index pin etc. So, my thought was that the threads were cut off, or the shoulder on the sleeve was not square. Likely the latter was the cause, given the well known high quality of their work in general.

yes, off to the range. as soon as I can grab some shop time to load some ammo.