

The bolt/slide would be in the upper chamber, with the magazine feed in the lower chamber.

So one could theoretically go with an over/under styled design. Minimize maintenance and moving parts due to force. Minimize the possibility of a failure to extract. Mass (heftier to deal with the forces involved) Well.take into consideration if someone were to try to make a handgun which uses a rather large round, you'd need to fit a lot of requirements.
