You are right, the 7.7 semi rimmed is different than the 7.7 rimless used in the rifles and LMGs. There is talk at the Japanese board of filling down the rim and then using the semi rimmed in rifles:I came across one today at a gunshow. I take it the "7.7x58 semi-rimmed" ammo is not the same as Type 99 rifle ammo. P.S. The post time is WAY screwed up.