My friend is getting his father's pre-ban Colt, which we're sure is just your standard 20" AR15.  The rifle has only fired about a hundred rounds and was purchased new in the early 70's.  

Anyone have any clue as to what twist it will have?  He doesn't think it has a forward assist either, when did they add those to ARs?  Any place on the net where I can get some information on these differences between SP1, Sporters, ect...

Thanks,
Chris

1:12 twist. For more info, go to [url=www.biggerhammer.net/ar15/]Bigger Hammer[/url].