I'm trying to find this screw due to a stripped out head. I've tried Gun Parts with no luck. My ID of this gun is Colt Police Positive, .22 WRF,1st issue, Model G, sn 2605. Mfg. 1910 , blue finish, adj. rear sight windage only. Last Patent date on barrel is July 4th,1905. Anyone know where to find one or the size of it ? Thanks.

