[i]Q. Regarding barrel burnout of Gov't. Ml6's with the 1 in 7" twist - about how many rounds have to be fired before a performance degradation is present? Does the SSlO9 cause more rapid barrel wear than regular "over the counter" ammo with heavier bullets?[/i]

A. Gov't. M16's can show throat erosion after as little as 2,500 rounds. However, that is with the lighter Gov't. profile barrel and always under full auto conditions. Under semi-auto conditions, those barrels will typically go 5 to 7 thousand rounds before breaking down badly enough to warrant replacement. Many times, a Gov't. barrel with 1 or 2 thousand rounds will be replaced as inaccurate, when what it really needs is to have the copper fouling removed from the bore. This is a tedious job, but the reward is a "like-new" barrel. This refers only to chrome lined barrels like ours or Colt's.
Mil spec. SS109 ammo will not measurably increase barrel wear under semi-auto fire and our mil. spec. (chrome lined) barrel will outlast any sporting rifle barrel - period. More barrels are ruined from over cleaning - or careless cleaning - than are ever "shot out". Chrome lined barrels really only need to be detail cleaned when the groups start to suffer. Otherwise, a little powder solvent (or "Break Free" with CLP), and a few passes with a brush, clean the chamber well, dry everything off and apply a very light coat of "Break Free" or "Rem-Oil" and put it away. [size=3]We have had barrels here go 20,000 rounds and still be within mil. spec. when treated this way.[/size=3]