Quote History Quoted:
Weird. Every one of my 10+ PSA uppers have had this. I thought it was common knowledge from them. And really they aren't PSA, it's FN (on the Premium line anyway)
From Joe Weir:
On our FN sourced barrels, FN cuts the profile, installs the M4 barrel extensions, drills the gas ports, cuts and crowns the muzzle, threads the end of the barrel, roll marks the barrel, phosphate coats the barrel, does the high pressure test and Mag particle inspects each one. We do not get FN barrel blanks, we get fully finished barrels from FN.
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Synyster06Gates, Please post photo's, (Also StevenH, I still waiting to see photo's of the front of your carrier, since if the impacting denting is bad enough to the front of carrier, could cause the carrier plating to flake off).
I would like to see if the indents are consistency on the left hand lug location of all (such as in part of the barrel extension installing process to the barrel), or if these marking are more of a cosmetic identifier on the barrel extension instead (why, i don't know, since the barrel extension feed ramps are visually different on a M-4 barrel extension verses a standard barrel extension so they really don't need to be marked in this fashion on a bearing surface).
On a standard barrel extension, the feed ramps start point are flush to the OD face of the barrel extension line, while on a M-4, the start line of the ramps are recessed back down from the OD face line instead.