Originally Posted by
Der Gebirgsjager
I'd sure have to go along with TbG's assessment of the rifles under discussion.
Tula is a very old Russian (Soviet, depending on the period of history) arsenal located in a town by that name, and established by Peter The Great in 1712. No, I wasn't there! So, during that time, they've made lots of different firearms of various designs, among them Mosin-Nagants of various models. Mosin was a Czarist army officer who suggested a few design changes to the 1891 model rifle as designed by Nagant, who was a Belgian. So the rifle design, as finalized, became know as the Mosin-Nagant. So basically what you're asking, and the answer, is that the two rifles are the same, Tula and Mosin, but the Tula is made at a specific arsenal and those categorized as "Mosin" could have been made at any of several other Russian arsenals which produced the same design rifle.
As for the Swiss K-31 and M-11, those numbers indicate the dates of adoption by the Swiss Army, 1911 and 1931. Both are straight-pull actions rather than the more conventional turn-bold designs (like the Mosin), and the significant difference between the two is that the action (receiver and bolt) of the 1931 is redesigned to be more compact (shorter) than the 1911. Either one is a fine rifle for target practice, and sporterized can make good hunting rifles. They are both known for fine accuracy.
I acquired both a M-1911 rifle and carbine back in the '70s, but eventually sold the rifle as being just too long and cumbersome. When it had it's immense saw toothed bayonet attached it was the longest rifle that I've ever owned, kind of harkening back to the Swiss Pike men of the 1500s and the Vatican Swiss Guard. If memory serves, I acquired them for about $100 each, but at that time the M-1931 was almost unseen in the U.S. because it was still issued to the Swiss reserves. I only ran across two of them during that time period and they were going for about $750. Eventually the Swiss let go of them, and for awhile they were selling here for around $250, but the price has climbed again. The Swiss take good care of their guns, and for the most part their surplus rifles are in Good - Excellent condition.
This is not necessarily true with the Russian guns, some of which saw very hard times in WW II. Many underwent a reconditioning process after the war, and it's something you should study into a bit before buying any Mosin-Nagant rifle for almost $300! A few years back they were selling for $65. To a collector, a nice one with all original parts may be worth $300, but many that were reconditioned have what are called "force fitted" parts with electric penciled serial numbers of the replacement parts to match that of the receiver. I really don't think that I'd buy a Mosin sight unseen unless just looking for a shooter, but might take a chance on one of the Swiss rifles.