If the T/C chamber headspace is cut to SAAMI specs (short) and the Hornady ammo is dimensioned to milspec (long) then the T/C interlock safety will prevent the hammer from hitting the primer with full force. The result is usually a dented primer and a misfire - as your friend expereinced. This happens often when a reloader does not set the shoulder back far enough on any bottlenecked case. I do not know the dimensional differences in headspace are between the two specs, it is probably not much but obviously here it is too much. Perhaps T/C could change their chambering specs, or not. My advice, just get the Remington ammo.
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