I just ordered a King Arms M4 from Airsoft Global. I've some concerns about the internals and how they'll interact with the the only battery available for KA modstocks AEX has (
http://www.airsoftextreme.com/store/index.php?main_page=product_info&cPath=480_94_102&products_id=3610).
I already stripped the piston in mine but I'm using a 11.1 Li-Ion... stick to the 9.6 and you should be golden. I put in a ppa110 spring hitting 389-396 fps, drop in a "ppa100" and leave the piston head stock, you should be in the 340-360 range... leave the rest alone, it's pretty good. good luck bud
Sorry for the late reply man but he's right. In stock form that spring acts more like a 100 since mine stock was only shooting 290 FPS. All I did on mine was put an M120 and it shoots around 385-390 FPS. Everything else is stock since I'm a believer of "if it ain't broke, don't fix it." But besides that, the internals are all reinforced nicely. And yeah stick with a 9.6v and it's fine. I actually use a 10.8v and its fine. That's probably because I only play once every other month though. Hope that helps. It's a good gun though! Best value bar none.
