I'd like to put together my own civilian model M4. This is the starting point of my research and I am looking for some experienced opinions on which manufacturers I should be looking at for the individual parts and pieces of my rifle. I'd only like to spend between $800 and $1000 but I don't want that to limit your input nAlsp, is it true that .223 ammo is all but impossible to acquire? How much more money am I looking at spending in assembling my own rifle, rather than just buying a complete one? Thanks for your input!