Lloyd,
I have a Contender Carbine in .45-70 and upon inquiring with T/C about maximum pressure, the reply was, "Trapdoor pressure." When I further inquired what Trapdoor pressure was the fellow replied, "28,000." If you prefer to get the answer straight from the horse, T/C's number is (603)332-2333. I would also like to say that this carbine is a hoot to shoot!
Good luck,
Jeff