The MB mark on the barrel is the test firing proof mark, as documented by Webster. The other mark that I have seen which looks like interlinked ovals is not mentioned in Webster. I have been thinking that it was the inspection mark for the barrel and somehow overlooked by Webster.
As you know, I am in the process of collecting pictures of various 1891 Argentine markings. My recently acquired 1891 rifle has the interlinked ovals, but there is a grey area around the marking. In the past day or two, I have noticed three or four rifles from Gun Broker auctions that have the same area around the mark.
Given that the interlinked ovals are not mentioned by Webster and having collected some pictures of barrels with just the test firing proof, I am starting to wonder if these interlinked ovals are not a mark that was applied at the factory before bluing, but maybe applied later somewhere.
Any ideas of why there seems to be the grey area around the mark.
the interlinked ovals mark seems to be quite common on 1891, my carbine has it as well (not greyed out). I've also seen a pic of a carbine with replacement barrel (arsenal done) and this mark: http://forums.gunboards.com/showthre...gineer-carbine , post #1
My carbine is shown in post #24 (please forget about the Chile nonsense i've written there).
Thanks for the link to that thread. My searching had missed it because there was no 1891 in the title. Two more carbine examples for my picture collection and spreadsheet.
The first example has both the AG-shield and the ovals. I don't remember seeing any AG-shield barrels having the ovals.
Your picture seems to have that blur around the ovals that I am talking about. Maybe it is just a reflection. I think I have examples of the ovals looking pristine, but did see several having that grey blur around the edges. I looked at mine with the 40x magnifier and it is definitely a lighter grey color than the rest of the barrel finish.