You may not have had the pleasure of getting handed down a M-16 that had been fired on fully automatic for a few years with bores that looked like gravel. I applaud your luck. Our platoon was handed POS's. Lucky you.
They are out there. And good ones too. But I can tell you a smoothbore mini ain't going to shoot any better...
Comparing a pristine Caprice to one with 300K miles ain't fair...
