I love my C3. Super neat little pump, just terribly built IMHO. The barrel is plastic and non-replaceable, the junction between the combustion camber and barrel is an interesting U-shaped piece that has an o-ring on it to seal the two together (most common issue with C3s was that o-ring would fail and has to be glued in place just right in order to seal again), the entire thing is really difficult to service yourself
(granted from what I've heard Tippmann and Tippmann dealers used to service these for free regardless of who owned it so long as you were willing to ship it in), pump stroke is ridiculously long but not overly hard if well lubed, and yes it does get hot if you pump fast enough. I figure that may be part of the reason, along with any blow back from the combustion being used to recock the marker risked excessive wear on the bolt. I for one would love to have a semi propane powered marker.
Still get kicks out of taking my C3 to the field and then at lunch taking the tank off and hooking it up to my little grill. Scared the crap out of people.