Has anyone attempted to use either caliber in an ar15 and does anyone know of a source for barrel and bolts? I wanted to get a Bowen Alpine Redhawk and an Ar 15 barrel and bolt in the matching caliber would be nice thanks.

Quoted: Has anyone attempted to use either caliber in an ar15 and does anyone know of a source for barrel and bolts? I wanted to get a Bowen Alpine Redhawk and an Ar 15 barrel and bolt in the matching caliber would be nice thanks.

The rim on the .45 Colt and Casull is .512, roughly the same as the .50AE.  Your challenges will be a) avoiding bolt lug shearing and b) feeding.  The .454 Casull I would give the lowest probability of success as it is longer and runs at a higher pressure.  Feeding the long straight cases proves next to impossible (ask either Tony, Randall or myself, we've tried).  The .45 Colt could perceivably feed from Desert Eagle mags, but these have an issue in that the angle at which the top cartridge is presented to the chamber varies with the number of rounds in the mag.  Then there is the issue with the rimmed round and making the chamber such that the AR extractor still works.  Tony Rumore built all of 4 uppers in .44 Magnum and after that stopped because they are so difficult to get to feed reliably.  

So in a nutshell, it could be done, THEORETICALLY, but your probability of success is likely to be quite low ...

Thanks for the information marty. Guess I'll have to go with a Marlin 1894 then.

beowulf rifle and revolver.

Maybe you could make one using the 45 win mag case?  Should be close in performance.

to shoot a 454 you would have to sell your car. Ammo is verrry pricey.