Well, I went and did it, I put a ofna/picco .21 and a massive fantom works pipe into my rusty yesterday. It wasnt cheap but I had to try it. Finished it late last night and at 11:00 pm I was in home depot`s parking lot breaking it in, Let me tell you this thing is crazy fast. Not knowing where to start with gearing, I rolled the dice and put in a 70/22 combo and so far it seems to be good all around , after more testing, I`ll know for sure. And I`ll keep you guys up to date on how the tranny holds up, I wish someone would come out with some stronger tranny gears, right now I`m alittle worried about it, so I set the slipper at half turn. Hope it helps some.