I found this in the history porn subreddit: http://imgur.com/7rr1gYR
Was this common? I can't seem to find much information about it. What is the most drastic example of out dated weaponry being used in say WW2?
Was this common?
If by this you've meant "Maxim usage in RKKA" - then yes, it was in every infantry unit, especially in 41-43.
I can't seem to find much information about it.
Where did you look? Maxim MG was produced in Russia in huge numbers for a long time. It has very reliable and simple construction, very cheap - just need a lot of low-quality metal. Yes, it was heavy and with relatively slow fire rate, but it doesn't need frequent barrel replacement and barrel itself didn't require special steel with rare metals.
Primary reasons for Maxim usage by RKKA in WW2:
attempts to design and produce reliable mounted MG for rifle cartridge (e.g. 7.62 mm) has failed in pre-war years. DS-39 was complex, unreliable and expensive in production - much of its problem came from cartridge's rim. Gorjunov 's SG-43 was ready only in 1943.
Degtyarev DP/DPM, adopted in 1927, was rather decent LMG, but disc magazine has its problems (heavy, prone to damage, low capacity). Disc was chosen in turn because cartridge 7.62x54R has a rim. It was much lighter than Maxim, but not as precise in stationary position. Also, Maxim could provide suppressive fire for a long time and could be fed from a box. DP was good in attack, while Maxim was better in defense.
most efforts in MG design were focused in HMG (12.7 mm) and quite remarkable HMG was designed in 1938 - DShK (Degtyarov - Shpagin large-caliber, 12.7 mm).
Also, a lot of efforts went into MGs and automatic guns for aircrafts - like ShKAS, ShVAK etc.
RKKA situation with MG mirrored Heer situation with HMG: germans have great MG for their rifle cartridge, but didn't manage to design and produce HMG. And while MG42 was a great gun, it could eat up all ammo real quick.
What is the most drastic example of out dated weaponry being used in say WW2?
I would nominate russian imperial guns on wooden wheels. 6" siege guns, first used in 1877 during Russo-Turkish war, were used in a pinch against german tanks of Guderian 3 and 4 PzD near Tula in October of 1941. Those guns were already worn out by 1905 and sent to Tula's Arsenal warehouse. Anyway, when Tula's defenders lacked in AT guns, they turned to Arsenal and they produced these guns - plus some barely matching british 6" cartridges (~40 kilogram of explosives). These guns were firing in direct view of advancing tanks, at 500-600 m distance. At first, germans thought they encountered some superheavy AT mines, as close hit was strong enough to flip a tank or put it on a side. Direct hit means hull penetration and a lot of twisted metal instead of tank. Tank battalion lost about company and stopped advance. It saved enough time for reinforcements to arrive.
Sources
russian 6" old imperial gun at Tula in 1941 - with photo
Guns.Ru - Maxim M1910/30. Note that last modification was in 1930.
Guns.Ru - Degtyarev DS-39. DS-39 was based on DP, but less successful. Belt feed didn't work well.
Guns.Ru - Gorjunov SG-43. Heavier and slower than MG42, but good enough to keep it until 60s.
Guns.Ru - Degtyarov-Shpagin Krupnokaliberniy DShK-38. Based on DP-27 and proved to be quite reliable and successful. It is still in use in Afghanistan and Pakistan - for example.
Not an expert on this but know a little bit about it as a hobbiest.
The PM M1910 was still in common usage in the Red Army for much of WWII. I gather it was supposed to be replaced by the DS-39 but production for that was discontinued due to the onset of the war and the need to maintain high production. From 1943 the SG-43 Goryunov started to replace the old Maxim. I'm semi-surprised to see the wheeled carriage was still used for the Goryunov - I think its supposed to make it easy to move about... but I always figured the carriage would be heavy and awkward on uneven ground.
I suppose one thing to keep in mind is the Maxim machine gun was still perfectly functional even in WWII. I don't think there was ever an instance of German troops saying 'don't worry, they haven't got modern machine gun'. It wasn't as impressive or as flexible as say the MG-42, but it did its job reasonably well.
In terms of outdated equipment being pressed into service in WWII, the first example that comes to my mind is the FT-17. A French tank that gave decent service in WWI... but didn't really impress anyone in WWII with its armament or relatively weak engine.
EDIT - found a link that wasn't Wikipedia, covers the DS-39 and SG-43 briefly. Also notes the relatively high production of the Maxim design pre-war. Doesn't explain why this was done, but might have been a factor in delaying the rollout of a replacement - governments and armies prefer to use up what they have in stock if they think it will be cheaper.
You had the English & Commonwealth using;
P14 (Enfield Pattern 1914) rifles as their marksmen rifles.
Some Commonwealth forces (India & NZ IIRC) making use of Martini-Enflield rifles (Original service 1878-1902).
English & Commonwealth forces using the 1912 Vickers Medium Machine Gun
The English and some Commonwealth forces using Webley No. 1 Mk. 1 revolvers (Entered into service in 1880)
What should be noted is that the PM 1910's that the Soviets were using may actually have been reproductions as they manufactured some of them from 1941-1945.
Keep in mind that it's been a few years since I did any heavy reading into this so my info may be a tad outdated, and perhaps other folks can fill you in other countries since I'm only really familiar with the English/Commonwealth side of things.
Edit: Don't get me wrong, if the weapon isn't broken then you don't need to fix it (Especially if your troops are familiar with them), but there were much more effective weapons that could have been utilized.
Edit 2: Fixing some some missing words/spelling errors.