What is the longest barrel one could order from Remington I have model 31 with a 34 in full barrel. I don't know if my father extended the barrel himself or if it could be factory length.

Curious as to how a person extends a barrel? Is there a welded on segment?

I believe 32" was the longest model 31 barrel and I have a couple of extended barrels and if you look close you be able to tell.

Can you tell if there is any choke (constriction) in the muzzle of your 34 inch barrel to match the "full" designation?

Bobcat

I can only tell you how my father extended barrels it was done with a lathe. The original barrel would be cut and turned down then the extension would be a larger new piece of steel turned to fit the original barrel then the entire barrel would be turned and honed. Then he would resleve the barrel or make it acceptable for screw in chokes or drop in chokes. Then add the bead or appropriate rib for the barrel, then reblue. I had too take the barrel off but was able to locate where he extended it.