I have a new Seekins SP10 on way. I don’t yet have a shorter magazine (less than 20 rounds) to accommodate shooting off bench due to mag protruding lower than grip. Is it possible to insert 20 round mag, chamber 1 round, then remove magazine. Will it shoot and eject with no magazine inserted? Is it safe with respect to exhaust gases exiting thru magazine hole? The first shooting will be sighting in the rifle. Just wondering if that is possible using factory supplied magazine but removing it after loading.