I have an older Sendero in a HS precision stock that I would like to add an ARCA rail to where the current swivel studs are located. Has anyone found anything that would bolt up flush to the fore end while not having to make mods to the stock.
For all those looking for the lightest, smallest ARCALOCK rail on the market – here ya go. Weighing in at just 1.5oz, this will fir forend hole spacings of 2″-3.5″, just like our extremely popular IBR. The rail will also come with t-nuts and hardware to allow you to install the rail closer to...
Salmon River Solutions (SRS) makes a few different models of ARCA rails with a radiused mounting surface to fit better on rounded bottom stocks.
Here's one that would probably work without mods: https://www.salmonriversolutions.com/product/srs-4-arca/
Note that your sling studs might be 10-32 threads, which he offers hardware for as an option. If not, you'll need to hit up your local hardware store for the two fasteners you'll need.
Do consider modifying that stock - even one additional threaded insert would allow you to run a full 10" ARCA, which would open your options for bipod and tripod positional work. SRS has other models with that rounded bottom that would work well.