Actually the 1903 Springfield wasn't designed here. The US even paid royalties to Mauser for the right to manufacture it. Don't know how long the payments were made. There were changes made, of course, but it's a Mauser. We also used the Hotchkiss light machine gun but Hotchkiss was an American, I believe, but he had moved to France.
My son, by the way, is serving in the US Army as a tanker, presently in Northern Iraq. Their base is in Germany where there were German troops sharing their barracks, sort of. They actually had a range on-post and he had an opportunity to fire a G-36. His issue weapon is an M-4 and I don't recall him saying that he was especially impressed with the G-36. Interesting and different, perhaps, but not exactly decades ahead.
On the other hand, firearms design only rarely has a great leap forward, as happened when breechloader replaced muzzle loader, then repeater replaced single shot, then autoloader replaced manual operation. It usually doesn't sound like people around here think there was any advancement at all when the M16 was adopted.
Shoot low, sheriff. They're riding Shetlands!
Underneath the starry flag, civilize 'em with a Krag,
and return us to our own beloved homes!
Buy War Bonds.