So it can be done.
 

Check this auction out.

http://www.gunbroker.com/Auction/Vie...Item=257394548

Trojan Barrels fitted to a P grade.

I have seen it done a number of times. The only issue is filling the doll's head slot in the top of the breech and what to do about the useless "extension" if you are using early Trojan barrels. I know of a D grade hammer gun that has 2 sets of Trojan barrels fitted to it.

I have seen the question raised before about doing it, but this was the first time I had actually seen it done. I guess in a pinch it works.

"graded" barrels are preferred for barrels swaps and there are plenty of issues fitting them from one gun to another.

On non ejector barrels, the extension or lack of it is only decorative and can be sawed off. How you fill the void left by the sawed off extension or dolls head is up to you.

I could see other graded barrels being fitted to a Trojan easier than visa versa. Remove rib extension and fit. However in any case, work would have to be done to the forend lug.

If your gun happens to be a later Trojan with no rib extension the process becomes very much more doable.