I have standard two-piece 1" scope rings for my Model 70. How do you determine the Allen screw size if you want to replace them. Are all these ring scres 8-40? What does 8-40 mean? Mine measure .461" long from head to tip. I can't find this size listed in Brownells. Where can I get replacement Allen or Torx screws without ordering a bunch?

Sounds like 8 gauge 40 tpi refering to the thread size. But I could be wrong.

Small screws are measured by a gauge size, with a #8 being .164" in diameter. 40 is the number of threads per inch. The 8-40 and 6-48 used to hold the mount base to the gun aren't common sizes that you can get in your local hardware store. Brownells will have them, but you may have to order a bunch.

Screw & bolt chart.
http://www.marfas.com/machinescrewtapping.shtml

Brownells screws. A couple of searches might get something closer to what you want.
http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=19929&title=LONG+6-48+%26+8-40+SCREWS

Bye
Jack

Small screws are measured by a gauge size, with a #8 being .164" in diameter. 40 is the number of threads per inch. The 8-40 and 6-48 used to hold the mount base to the gun aren't common sizes that you can get in your local hardware store. Brownells will have them, but you may have to order a bunch.

Yeah the caliper says .1635. So I guess I have 8-40s. Whis you could buy just a few of these somewhere.