Quote:
The M12 28 gauge had 2 & 7/8" chambering- the front of the ejection port would most likely
be "re-radiused" to allow a spent 2&7/8" length hull to clear


My M12 28ga has a barrel stamped for 2-7/8" chamber, but I have not compared that port to my 2-1/2" 1912 20 ga. The 20ga short chamber gun has no trouble ejecting 2-3/4" hulls.