...said 10 foot lance was still issued in the official TOE of British units up until Operation Market Garden when they finally realized it was unwieldy for paratroops.
I thought they went to the folding model for Operation Market Garden?
As to the photo, that is the famous "Half High Pressure Bullet". The case was loaded while on it's side, Bullseye powder on the bottom, then a layer of Trail Boss, no less than 80% of the available volume, then the bullet seated with the gas check side down to match the Bullseye level. Care must be taken when chambering the round, since chambering it with the Bullseye side up will result in increased velocity causing a change in impact and making it capable of taking even the largest game animals. Chambering it with the Trail Boss side up, it is suitable for use as a Gallery Round, being subsonic and not penetrating more than one layer of ordinary cardboard.
Ed
