Svt-40 I think you need to check out "Hastings barrels" they carry cantilever scope mounts on shotgun barrels for a few popular shotgun models. To get any degree of hunting accuracy you really need iron sights or a scope (lots of eye relief though!)
If right now, all you have is a front bead, do your wallet a big favor, and stop until proper sights are mounted!
Some newer shotguns have holes drilled for a weaver scope base on top of the receiver, but not all, S&K company makes scope mounts for a few shotgun models too.
Numrich would be a good option too for shotgun barrels.
Can't remember if they are subject to USA export laws though?
Anybody here know?
Plus, put a "WTB" post on the EE here....periodically check out new posts in the parts & bits section....
Cheers and good luck to you.....