The early T3 was used in at lest two different campaigns in the Pacific during WW2. Okinawa and in the Philippines where it performed very well. The M1E7 was made up by Inland and the commercial scope was the only one available to them at the time which was the same as the military version used on the 03. But the scope could not take a beating and it was discontinued by the military as not practical. No scope was really needed out to 150 yards like they thought a carbine sniper would have performed best at. Iron sights were more then enough as the M1 carbine was not an accurate target rifle. And fighting house to house a scope only was a hindrance.