modify a longer rail so it bolts up to your shroud..
drill your own holes in the rail so it matches up to the pattern on the shroud, and use the screws & backing plate from the factory iron sights to mount it to the riffle..
if your worried about flexing/breakage of a longer rail, i would just cut a peice of sheet metal ( 16 ga. or so ) into the propper length/width to exactly match the bottom of the rail
then use an epoxy or urethane adhesive to glue it to the bottom of the rail.. Gorrilla glue is excellent stuff, so is Hi-Bond epoxy ( both found at home depot)
the next concern i would have , is that those factory screws that did the job for the ironsights, wouldnt be long enough to bolt up through both the rail and the metal backing plate..
so i would drill holes completely through the rail, as a countersink..
where the bolts would set on top of the metal backing plate when everything was bolted down, the heads of those bolts will sit nice and snug in the countersunk holes drilled out into the rail.
can bolt everything up to the riffle through the metal backing plate. if you use gorrila glue ( urethane) or Hi-Bond epoxy ( yup, epoxy) either one of those will hold the rail onto the metal backing plate no problem..
and...
i have seen rail mounted reer peep sights on ebay, seems like they were pretty reasonable if i remember correctly
just trying to help out, or something i wrote might even give you some ideas of your own that could help get the job done..
anywho! good luck with your project, let us know how it goes..
and post pics of that sweetie pie when she is all dressed up and ready for action! :wink:
later bud , Allen