barrel steel
Sir;
Sir, as has been stated, 4140 is a chrome molebdenum steel with 40 points of carbon and 1140 is according to Ackley, " free cutting screw stock" - yet it also has 40 points of carbon si it will "heat-treat."
I would be very cautious about "turning down" the blanks you will have too much.
Depending on the heat-treat administered both steels are adequately suited for shotguns, but I wouldn't go lighter than industry standard.
Mossber, to my knowledge has never had barrel problems; most problems are caused by handloading practices!
It is my personal opinion that 1140 of sufficient thickness and heat treat is the better steel for shotgun barrels although 4140 is a stronger steel - if heat-treated wrongly it might be more likely to shatter.
Harry B.