WB
The grip/stock screw is 1/4"-28 normal thread
Friday, June 14, 2019, 07:47

My Pachmayr grip uses a 1/2" long allen bolt. I read that typically from the factory they are 1.5-2.5" long. One in my desk drawer is 2.5". There is quite a bit of room for error as the "stud" has a good 1/2" of threads internally. You don't have to go crazy torquing it down, just nicely firm. You can split wood, and if left shakey loose recoil can also hammer and split the stocks.

Usually at a hardware store the 1/4" allen bolt is less than $1. The forend screws can be a little tricky. They USUALLY are 10-32 screws in an assortment of 3/8", 5/8", and 7/8" lengths depending on the forend used. I HAVE seen 8-40 metric screw holes in barrels too. However they are easy to trim to fit. The washers are more of a pain. Many use rubber 0-rings but they deteriorate quickly. The hardware washers usually are too big in O.D. I make something to use on a drill and with a file I spin them and grind to fit the stock hole. Aluminum or brass is easier to work with than stainless. I delight in going to the hardware store and getting screws and bolts they charge $5 each for online. Why piss your money away when there is no need of it?