I wanted the optic to be quick-on, quick-off but off course with no loss, or minimal loss, of zero. The range for bowling pin shooting is 25’ but the optimal part of the pin to hit is maybe 2 ½” wide. Of course there has to be some clearance between the optic mount and the T-slot if goes into, otherwise it’s not a slide fit. There’s probably about a thou there, and it's about an inch wide at the base. That gives a theoretical variance at 25’ of about 5/32” to either side, too much really, but I’m pretty sure that in practice it’s going to be much less.
I wanted The Colonel to be able just slide it in and have it click in place, then actuate “something” and slide it back out. I spent as much time coming up with a simple way of doing it as I did actually doing it. I had pictured a nice checkered Delrin button that the user could slide or pivot up or down that would withdraw a spring-loaded locator—I really wanted that but…. time! I wanted most of all that it would a no-tool engagement and release-- or maybe something where a cartridge could be used as the tool. The problem with .50 GI cartridges is that they resemble cigar butts and as tools are no more useful. A couple times I said screw it, there’s just going to be a screw and I’ll give him a wrench to fit it. I know from experience that just leads to trying to find the wrench.
I finally came up with this. A headed pin with a lifter plate under it and a spring over it, the lifter plate protruding out the side. It works fantastically! Trying to keep things “1911”, the spring is made from a 1911 sear spring. The lifter plate? From the rear sight of a Winchester Model 1910 rifle that broke in rough handling. This is the semi-auto in .401 Winchester Self Loading caliber; Winchester called it the Hammer of Thor and indeed it’s a thumper. This one happened to be second-year production, so…. 1911. Nice tough piece of spring steel. The pin, I usually have some ejector pins around but could not find one in 1/8 so I had to make a head and silver it onto a pin I did have:
They wound up looking like this, and I have added the pocket to the mount where they all go:
And it works. Installing it, the pin snaps perfecting into its hole in the slide. When it’s time to take it off, push up on the lifter and slide it off.
....and there are still a few things to do. I don 't like having things held together with screws so at the least there has to be some sort of extra measure to keep that little 2-56 screw holding the spring from backing out. It will get LocTite of course but it'll get something else too. I still need to get a little more weight out of the reciprocating mass. Right now with the optic on I'm at 3oz over that of my own pin gun. Probably OK but I want to be sure as time is tight. I know I can count on The Colonel to thoroughly test it but if he needs to return it for trimming that's a speed bump we don't need.