Rifles with side-mounted magazines and modularity

Question
Thank you for being willing to answer questions.

I like to imagine a modernized version of the old, abandoned "TRW Low Maintenance Rifle" idea, TRW LMR. I really think it would have been a more rugged, more sensible development branch for the M16. I think it should have been pursued and adopted by the government with great seriousness.  I want to realistically imagine my idea, so that my idea could be inserted in detail into my favorite pen-and-paper roleplaying game. My favorite game is the one called "The Morrow Project."

My questions are: In more detail, what is a feed ramp? If you built a rifle from the ground up and had your own factory with good equipment and customized parts, how easy would it be to make a rifle that could feed from either the left OR the right? The rifle needs to have a side-mounted box magazine that could be switched for left-handed or right-handed shooters. Is that impossible?

By extension, I also study the Australian Owen Gun, the German FG-42, the Robinson M96 with top-feeding modification, and various rare Nazi prototype rifles -- all with box magazines that feed from unusual directions (i.e., feeding directions other than from below.)

I wrote the Wikipedia article on the TRW LMR. I even used the Freedom of Information Act to get the Army to show me a document about the TRW LMR that had not been available to the public before.

Thank you.

Answer
When a cartridge is stripped from the magazine by the forward action of the bolt, the bullet is guided into the chamber by its sliding along a sloped metal area called the feed ramp. In some actions, once the cartridge is stripped from the magazine, it is not firmly held until the bullet is positioned within the chamber.  That type of feeding would not work for any magazine placement other than beneath the action.

In order to feed from left or right or above, the cartridge must be positively held throughout its traverse from the magazine until the bullet is within the chamber.  That is possible and is done in some actions.

Hope this helps!

Dave