關於退殼口既問題 - 無辦法之下唯有做自修全...好在終於揾到小小資料：
On the left is the Sport Model ejection port. It is the classic design and continued through the Mk II-Series of Hi Powers. On the right is a 9mm Mk III ejection port and factory barrel having a cutaway to enable visually checking the chamber without retracting the slide. Notice the lower rear of the ejection port. This slightly “beefed up” area reportedly helps prevent slides from cracking at that location. The Mk III ejection port somewhat resembles that of current 1911-pattern pistols, but without the “scallop”.
大概意思係從MK III開始Browning要改良到更加切合實際需要...所以除左系chamber鎗膛位整到可以俾射手隨時睇到上咗膛未之外重要改埋退殼口個型等個slide滑架唔好太易裂（下圖紅圈個位）...
