"Jam" narrows it down to about a dozen possibilities!
None of my Colts has been very ammo- or mag-sensitive; (assuming the ammo is to spec, and the mags are also as-new).
If the gun is reasonably clean and well-lubricated, I'd suspect extractor tension; too much can cause feed failures, while too little will result in poor extraction/ejection.
So, what sort of "jam" is it?