Buck and Ball loaded ctgs.(paper) were used by the US military up until about 1850 for their .69's in a ratio of 3:1 or 4:1 over single ball loads. These were made up in paper ctgs., with the buck shot over the large ball.
There is no wedging problem. I've tried them in my bro's 1728 Bess as well as in the pistols mentioned (.54 rifled and .58 cal. smoothbore. They are quite 'special' at close range.
The US military used them to increase the 'hits' on the enemy, even though the buck-shot 'hits' were only wounding hits at longer ranges.

In the 1960's, multi-bullet loads were developed for the .223's (& .308's) to 'attempt' to increase the 'hits' of the then-current soldiers. These apparently weren't very successful as they seem to have 'gone by the board' - or have they?