When you restore a military rifle, as with any other restoration, you have to be really patient and look around. The hunting for the parts is suppose to be part of the fun. It's not suppose to be an exercise in frustration. :-)
Keek checking online, and eventually you will find it. Also, go to as many large gun shows as you can, and look at the tables where guys have parts for U.S. rifles. You will eventually find one.
If I had a front cap and the only problem was that the screw hole was stripped, I think I would just casually talk to a few old grizzled gunsmiths, and as them what the classic trick is for fixing this problem. Alot of the gunsmith books from the 50s and 60s had tons of info on unusual tricks to fix common problems. People didn't just throw stuff away.
Just my thoughts.
Mannyrock