I fully agree with you that transfer ports in straight line to piston's axis give maximum performanance...air sealing by pellet skirt, pellets used to be of uniform size & should be little oversize to the bore...how many times I have seen people lauding the performance of pellet mfd by something like United Shot etc in IHPs...these pellets do not snug fit in the breech port and fly haphazardly after the shot is fired...only GSmith offers a tight fit...and to some extent Master Shot...most IHPs have poor breech locking systems and the leather washers used even out on the bore face/rim in no time...if you notice the O rings used in imported airguns...it has a longer and flattened top ...like what is shown in the picture below...these types offer better sealing...

thank you very much for sharing airdevil...you must continue to do so...