Since I already knew how to field strip the Colt SP1 rifle blindfolded (as a kid), the M16A1 was like being asked to learn how to ride a bicycle as an adult when you've been riding it all your life. ;)

I sort of want a M16A1

First gun was a 1943 Ishapore SMLE Mk.III* for Sidney I. Robinson Sporting Goods (now bought out by Cabelas, where I worked for 6 months) for $119.99. Still have it.

My latest was the Colt 1905 Auto posted below.