My budget would most likely cap around.. oh I don't know around $500-$600, I at first was thinking along the lines of a carbine length m4, but I would be fine moving to an m16 length because I don't know how accurate I can make the shorter barrel for long shots(Although that is really my job being the sniper, and my spotter running security). I was planning on obviously swapping out barrel and bucking and doing an r-hop at some point. I'm not opposed to opening gearboxes but It's not a big deal, I've just had some "fun" experiences fixing a few Echo1 gearboxes where the cursed Anti-reversal latch wouldn't stay in place requiring near 3 people to put it back together.