Mate...its not that we are trying to get at you, or not answer your question.
I for one, dont know off hand how to make any marker full auto.
If I did know..I certainly wouldnt spout it on here, to you, or anyone else. Firstly, because its illegal for you to do it and me to tell you how to do it...secondly, its not good for the sport...thirdly, we dont know who could be reading this thread, right now...you dont HAVE to be a baller to get on here, so..its best for all if we keep our mouths SHUT, about FA, whether we know how to do it, or not!!!
In answer to your question..sort of....there are few things that are imposssible, within the realms of engineering and electronics...however as has been said, once you modify something to do something it wasnt designed for, you are open to all sorts of problems, whether technical or law based...and where the law stands, it is quite clear (most of the time) what you can and cant do.
Hopefully...you are catching my drift..on BOTH paragraphs!