Attaching stuff to classic air rifles

[Dom_E]

Hi fellas, having got my first permissions the other day I'm now thinking about adding a sling and a bipod.

However most decent looking bipods I've seen attach to a weaver rail and I'm a little wary of screwing swivels into the woodwork for the sling.

Does anyone have any advice/pointers on these?

Cheers, Dom

EDIT: It's a springer, a BSA Mercury. As far as resale value goes it doesn't concern me greatly as I'm a user, not a collector.