I wanted some information on early wheel locks. The earliest example I have found was a pistol made in 1545,

http://pds22.egloos.com/pds/201208/11/23/d005...19e8e9.jpg

and the Charles V pistol, made around the same time.

http://www.metmuseum.org/toah/images/h2/h2_14.25.1425.jpg

But I have heard that they may have reached back as far as the early 16th century.
If you guys have any information or pictures, it would be much appreciated.

I can't find the reference right now, but as far as i remember the first self igniting lock concept used pyrrites and a rod rather than a wheel. But this was merely a concept drawing.

Many early firearms designs where hampered by lacking production capacity. For instance, breech loading was a known concept with plenty of custom made pieces made all the way from the renessance. But production technology would not be adequate to produce them reliably before the 1840's.
Similarly, the revolver concept was tried as soon as one had a lock that did not need to be wound up for each shot. But again could not be mass produced.

The date for the FIRST wheelock varies from source to source, and is set sometime in the first quarter of the 16th c. But we are fairly certain that they did not have a real impact before the middleof the 156h c. But when they did it changed the face of cavalry warfare in a couple of decades. (as described in Gordon Frye's exelent "From Lance to Pistol" feature)

There are a couple of wheellocks in Venice that are dated to around 1505 and there is is also a preserved drawing of a wheellock from that year in the collection of Martin Löffelholz. By 1517 wheellocks in the wrong hands were causing enough problems that Emperor Maximilian tried to outlaw their use and production.

Early wheellocks were not suited for military useas the the spring which drove the mechanism was mounted exteranly and therefore very exposed to weather as well as being easily damaged.

It is only in the last years of the 1530's that military wheelocks begin to appear in increasing numbers and the 1540's see an massive expansion of use as both wheelock arquebus and wheelock pistols are used in large numbers by first and foremost Germany cavalry.

As far as I have gathered, the wheelock was a sucsess with those who could afford it. Namely as pistols for the cavalry, and hunting weapons for the rich.
For "regular" troops who did not have the money to purchase them, or a watchmaker on call to fix it in case the spring snapped, it was simply not worth it. The lock works, it is just a real pain to fix once it goes "SPIONG!".

The snaplock, on the other hand, is rock bottom simple, and private and military use of firearms boomed (haha) once it was introduced.

Thank you for the information so far!
Were these early pistols ever used as side arms in battle? Would a fully armored cavalrymen have these weapons on a belt or in a saddle?

That depends on the era. Early in the wheellock's life, it seemed to have become a fairly popular backup weapon for primarily lance-armed, fully-armoured gendarmes; they carried one pistol in a saddle holster to extricate themselves from difficult situations once their lance was broken. Slightly later, the pistol became the primary weapon of a new kind of cavalry, and it was ideally used like a sword on steroids, being fired at point-blank range as the user charged home. This pistol-armed heavy cavalry (known from the late 16th century onwards as the "cuirassier") carried at least a pair of pistols in saddle holsters and sometimes more (one or two tucked into the sash, or the boots, or additional holsters, or just any other space one could conceivably jam a barrel into).

I have found some new information in a link that was very helpful,

https://mywebspace.wisc.edu/celast/ren_warfare/95_brooker_graz.pdf