Originally Posted By Sixgun357:
Also I read somewhere there is some history behind the original version of this rifle, what were they originally designed for?
The original AR-18 (Select-fire) was designed to compete with the AR-15/M16. The AR-18 was designed in about 1963. Obviously the attempt to compete with their own earlier product, the AR-15, was not successful and whay it was not successful is a story that would fill a book.
We've been getting some reports back from the Afghan for a few months now indicating performance problems with the short barreled variants of the M16. Interestingly ArmaLite had about the optimum barrel length in 1963 ! The AR-18 and later the AR-180 had 18" barrels, 1:12 twist, producing 3250 fps MV with a 55 grn bullet.
Drop down to the AR-10 and AR-180 Forum and visit at your leisure.