Tikka UPR Stock Question

[DurangoAl]

I am planning to mount a bottom pica rail on my UPR for a tripod mount. When I took the gun apart today to start planning out how/where to put the tee nuts, I noticed there is a hole in the forestock, only on the inside, it doesn't go through the stock, but there is a nut bedded in there that has the same thread pitch as the swivel studs.

Here's my questions:
1) what is the hole/nut for?

2) do you think I can drill out the underside of the stock and use that as one of my anchor points for the pica rail?

I have a call into Beretta tech support, but no word from them.

Thanks!

 

[1911Shootist]

All of the plastic Tikka stocks have 2 threaded inserts and usually only the front is used for a swivel stud. I’ve mounted full length SRS ARCA rails to them using both inserts with good results. The UPR is a composite half shell design, so it’s a little different, but I’d start by trying to use anny built in fasteners over trying to drill between the halves for tee nuts. Probably could drill a small pilot hole down from the top, then use a larger bit from below just until you contact the metal insert.