Go to this website for that info on NRA prone, LR and Palma shooters.
Sign In - Long-Range Target Shooting
Second, I would not waste my money trying to take a stock Hawkeye into a NRA LR prone/palma gun. No stocks are available and a custom one will cost you more than a complete used rifle.
Buy a savage palma gun for $1000 or watch the website above for good used prone/palma guns. Plus you will need a prone sling, gloves, cheap coat etc, which are often for sale there
is the website for savage rifles and parts.
I would post a wanted ad there for an entry level prone/palma rifle also.
Sinclair international and Creedmoor sports have great websites and catalogs.