Is this trapdoor loading unique?

[Garvin]

I think it is unique, most trapdoors allow you to push the pellet into the rifling. That Browning one is just dropping it into the breech - does something push it into the rifling or does the pellet jump into it on firing? If the latter it is a shit design.

Although the pellet makes a similar transition from the loading tap into the rifling on the BSA/LJ underlevers and they're still capable of great accuracy. I suppose the alignment of tap and bore has to be spot on, and soft lead presumably allows a tiny margin for error here?

[45flint]

Although the pellet makes a similar transition from the loading tap into the rifling on the BSA/LJ underlevers and they're still capable of great accuracy. I suppose the alignment of tap and bore has to be spot on, and soft lead presumably allows a tiny margin for error here?

Good point, kind of similar. I have found the AirStar to be very accurate, but it's as everything else on the gun, uniquely strange? The loading port as configured lets the AirStar have one oval O ring seal above the opening. The other systems have two o ring seals one on each side of the opened breech.