Well, being it is a shotgun it probably lacks rifling which is needed to keep bullets from flying like knuckleballs. I suspect the action to be strong enough to fire a 45LC provided it would chamber, but even true 45/410 barrels are notoriously innacurate with bullets due to the long jump to the rifling, which you don't even have. A rifled slug or rifled choke with a shotgun slug would be your best bet, and would be effective out to 50 yards or so on deer, IMO.