I see Brownell's in USA lists many - but have to know what size first - #6-48? #6-40? #8-40? And not likely going to be able to buy one - more like minimum 12 or so. If you have rings, likely want to replace all the screws so to have matching heads? Once you can identify exactly what you need, is possible a CGN'r might have a loose one or two in his "goodie box", but have to know what it is that you want - size, threads per inch, head style... You will have to be very lucky to get "a" screw that fits to a "might be" Leupold ring. I am sure that I must have 8 or 10 different screw sizes and lengths from various Redfield, Leupold, Ruger, Parker Hale and Weaver rings- sometimes different even within the same brand going from one style to another... I think the "kit" of scope mount screws that Brownells sells has 12 different sizes.