Refurb or QC proof mark

[Matchka]

Checking out the usual forums and YJ's with differing opinions. Does this diamond stamp indicate a QC proof mark, or is it a refurb?

[pcke2000]

it's an unidentified refurb arsenal stamp.

[running-man]

There are no upper receiver cover qual markings. Minus the arsenal mark and date, came from the arsenals clean as a baby’s bottom. 

[Phosphorus32]

The link below is your best online source for Russian refurbishment markings. As pcke and Alex point out, the diamond marking is currently in the unidentified category, with respect to location and ABF number, but it is clearly a refurbishment marking. YJ's site is full of out-of-date (euphemism for wrong) information, so it's a bit of a minefield.

//www.m9130.info/repair-depot-markings

[Matchka]

Tks all! Exactly the information I was looking for.