Rebuilt or Refurbished M59s: Were Any Upgraded?

[jmaurer]

A common "internetism" through the years is that lower numbers of M59s means that they were rebuilt to M59/66 and M59/66a1 configuration. I know that M59s commonly are found with 1TRZ on the stocks, electropenciled (possible) replacement parts, etc. I've reviewed the serial number lists for comments and searched the forum, but my question remains:

Is there evidence of M59s rebuilt with the characteristics of succeeding configurations?

[Greasemonkey]

I don't recall any M59s being "upgraded", I've seen more M59/66s dumbed down to resemble the M59. I believe in the "C" and "D" prefix you can find both models made and coexisting.

But to your question, does hard core evidence exist:  I think to "upgrade" a M59 after it was built, to M59/66 spec would seem to be more trouble than it's worth, when they could just build the purpose built rifle to begin with and probably build it quicker.

As for the 1TRZ stamp, I've found that stamp at least once on about every piece of Yugo surplus I have, be it any of the Mausers, even a Tito stamped German k98 with a laminate stock has a faint 1TRZ, the Tokarevs and SKSs.

[running-man]

I don't know that any M59 was converted to M59/66. I've heard that hypothesis stated around the internet since 2002 but I've never seen any data to back it up.  It just seems to me to be one of those internet myths that has gained traction to the point it's gospel now.  I personally think at some point the design was changed during/after the C series and an abrupt transition to M59/66 occurred in the D's. 

While not as distinct and noticable a change as say Russian SKS45s through the years, we know of small changes through Yugo production that lines up well with serial letter prefixes.  The fact these carbines all once had log books and the original importers kept the books with the carbines is invaluable in both verifying that Wythergild's letter to year translation is correct and also that the feature progression (phosphor to tritium night sights, ported to non ported grenade launchers etc.) occurred at distinct points in M59/66 production. There are always outliers of features that appear where they should not across all nationalities, but those consistently seem to be the result of some form of end-of-life builds, refurbishment, replacement, or bubbafication.

Now we know that The Russian and Chinese at the very least refurbished worn out/well used SKS carbines and scrubbed and restamped receiver S/N's so It's entirely possible that an early C series M59 could have found itself converted into a later letter series M59/66, but man, that's a heck of a stretch to say the Yugos definitely did that to mainly M59's when the easier path to generate that later series carbine was to manufacture it new just like the other 15k carbines in the same series.