Many of us in the U.S have so called modern military firearms, AR's,M1A's, and the list goes on and on and curious where in the world can a private citizen legally own and use such firearms?? Shoot at Camp Perry and our Canadian friends I am told can not have the AR15's, but believe they can have the M1A/M14 semi versions. Can those in Europe own and use such firearms?? Think they were banned in Australia??

Not too sure who was telling you the info about Canada, but they were wrong. Some of the confusion may lie in our classes of guns- Non-restricted, Restricted and Prohibited. Lots of AR's up here, but most are considered restricted, Some variants (ie. Robinson Armament XCR's, Tavor TAR-21's) are not restricted. Semi auto rifles are restricted to mags that are pinned to max 5, but Pistol mags (RA XCR pistol) are 10 rounds.
Also we don't have that silly US made BS that you have so we can get non-US HK's SIG's etc. sometimes, but due our small market size most stuff comes from US.

modern sporting rifles - my newest military rifle was made in 1942, in germany . i haven't ever owned a modern military rifle, as other than the garand, those are all full auto

In the RSA you may own semi-auto variants if you are so-called dedicated sport shooter. To be classified as a dedicated sport shooter by the police you have to belong to a sport shooting club which has to provide the police with a yearly update of your activities within the club.

We have a variety of US and European guns available in the shops although supply can be sketchy. My wife has a Remington R25 and I a VZ58, but still awaiting approval of the license to possess by the police.

With a couple of exceptions most hunting with semi auto rifles are illegal.