Take, for example the below picture:
Take out two pins and the upper and lower receivers come apart. I added the lower receiver with a collapsible stock and Persuasion (as I've decided to call my rifle) looks similar to this. The difference is that the rifle pictured is an actual M4 with a flattop upper receiver and carry handle mounted not to mention the fact that an M4 is full auto (the M4A1 anyway) and my rifle is only semi auto to comply with laws that civilians have to follow. In any case, once I obtain a flattop upper receiver I will do something similar to the next picture here:
Although after thinking about it, I'll probably put a scope onto the flattop and mount my red dot scope the the carry handle of the plinker. In any case, the primary point is this: ... actually, I don't really know what my primary point is. But I will make one up: AR-15s are easy to use, easy to clean, and easy to deck out in cool stuff without all that messy gunsmithing and drilling holes in things.While I'm on the topic of the modification of firearms, I've contemplated attempting to make a store that sells only two or three types of rifles, most definitely the AR-15 and AK-47 (or AK-74 which is an AK that is chambered for the lighter NATO 5.56 round that an AR-15 uses instead of the bigger and more destructive 7.62mm round). Maybe something else like the M14 or SKS. The primary reason: to have a store that a person can (provided they have a clean background check) walk in and purchase a rifle and all the accessories they have the desire to obtain all in one store at one time without all the messy hassle of ordering things off the internet. So instead of buying a rifle from the gun store, scopes from Dick's or Gander mountain, and mounting rails, grips, and forearms from internet suppliers, you could walk into SKIPPER'S and get it all in one place. And then try it out with the ammo you could buy there at the range out back. It's Genius!
