My experience with the LeMat is limited to one afternoon with a friend's Navy Arms repro. It was grand fun, and brought up fantasies of being on P. G. T. Beauregard's staff during the War of Northern Aggression.
I don't have weight specifications before me, but my subjective impression was of it being a solid, HUGE revolver. It had significantly less felt recoil than an equivalent-caliber Colt or Remington repro, due, of course, to the much greater weight of the leMat.
The "dreaded" muzzle blast and recoil with the shot barrel just wasn't there. Lots of smoke and flash, of course, because, being fairly sane, we were shooting black powder. It was nothing like a .44 magnum. I think we tore down some 16-ga buckshot loads to get number one buck, and also made up some with #4 shot. Neither shot load yielded patterns to write home about, but sure would have been combat-worthy at 10 or 15 feet.
This would have been a fearsome weapon to face in battle, but not particularly intimidating to use. It would need a proper holster and wide belt for waist carry. I understand more of these were carried in saddle pommel holsters than on the person. This was a very fun gun to shoot. My friend sold off the gun, for about what he had paid for it. Don't recall how much, but it was substantial.
Best,
RR
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