Looking for info/SSC9 arsenal stamp (poorly stamped 6603)

[Ravyn125]

The 10 mark is matched to the receiver not the serial. That was my fault for not clarifying. As far as the barrel; it may be original, but it was removed at one point(I'll post up my photos from working on it when I can). During installation whoever was doing the work didn't get it lined back up properly. It's a small amount and there doesn't seem to be an issue with a gap at all.

Best guess is that the front sight/bayonet lug are aftermarket or scrapped parts and the rear sight block was swapped when whatever work was done to the barrel.

[Justin Hell]

Y'know...I was so distracted by the odd sight leaf for the period that I didn't even notice that it was crooked too. I didn't know the 'n' leafs were also available in the pin thru type too? I was busy holding the brand new very old stock Russian leaf I had moments earlier opened in the mail...comparing the two, and I thought that was a late feature well beyond the 'n' period...more like the III or 3 types. I was under the impression that the 'n' ones were Russian spares sent along with the machinery, but I am not so sure anymore. If they were, there should have been an inspection stamp top and bottom before even seeing a gun.

It certainly looks like you will have pretty serious problems in the canting department. It will be interesting figuring out a way around that without messing up headspace. You might be in a pickle if the barrel doesn't have any room left to turn. I am surprised you don't have cycling problems since the rear sight block shouldn't be lined up properly to allow the operating rod under the rear sight to even be installed in the gun? Have you actually fired it or just heard of it being fired? I can see a single shot straight pull working, but I don't see how the gas system could be functional at all....unless the op rod was ground into an oval shape.

The front sight doesn't look disturbed, and might just be of low quality. The smaller later arsenals likely were using a mix and match of small parts made elsewhere...I think some rejects may have made it into the spare parts bins sometimes (if not all).   

The bayonet lug is also going to be the first place you seek leverage to improperly tighten the barrel...so it may have been deformed trying to squeeze more threads onto the barrel and into the receiver than there were in reality....or during it's initial removal.

[Ravyn125]

The canting is from work that was done to the front sight and the front sight is the only portion with the canting taking place. There were marks from tools and the pins were(very poorly replaced). The barrel is threaded properly and the head space doesn't have an issue. I've put 40 rounds through it without issue. The barrel was removed at one point but the headspace is right. The rear sight block isn't canted, just the front sight. More than likely whatever work was done was done on a vice and the front sight wasn't properly protected.