:)

Is not the design of a gun like airforce texan already perfect for high powered slugs? The blast of air comes from a bottle behind the slug, more like a muzzle loader, but doeas not have the downsides of a muzzle loader.

On the case of an impact shooting slugs. It probably can up to a certain caliber, but the design in it self is probably not the best for bigger calibers. The gun was originally not designed for that purpose, as it is a multi caliber gun. That means it has to be able to deliver low power also in caliber .177. Big bore airguns are designed only for that role, and doeas not need to meet the requirements of multi calibers, and different powers.
 
Lewis and Clark carried an air rifle muzzle loader with them on the trip to the west coast in the early 1800's. Was supposedly a very effective gun capable of hunting dear.

Actually it was a multishot breech loader if you are talking about the Girardoni.

"it had a tubular, gravity-fed magazine with a capacity of 20 balls. This gravity operated design was such that the rifle had to be pointed upwards in order to drop each ball into the breech block."

XP-Airguns.com make a Muzzle loader ... The XP Fifty Eight which comes as a Muzzle loader or a standard breech loader!
 
Wow T3PRanch that is just too cool for words! And if I know my friend Bob Vogel he probably has one in his collection... What do you think about the Minie ball design for use as slugs for airguns?

Well Chuck what I think is pretty much worthless opinion IF it is not backed by real world data derived from testing which I have not done being as I don't have an Air Muzzle Loader.

Having said that I suspect that they might work fine if the characteristics of barrel twist and velocity are similar to those by which the Minie ball was developed to shoot well.

Personally I would be more interested in a sabot carried round for a big bore that used a pistol bullet to attain a much higher velocity resulting in a much flatter trajectory and therefore better long range performance. To the best of my knowledge no one has yet made a sabot design that works well in an air powered gun.