Gunsmithing Help with drilling and tapping CZ action for scope base.

[BenY 2013]

So I love the CZ bolt action rimfire actions, however I wish the action was drilled and tapped for scope bases. I have decided I want to do this. I have several questions about doing so however. Do I need to drill all the way through the action? Or drill a "blind hole" (as I think it is called when the hole doesn't go all the way through)? Will drilling all the way through the action weaken it too much? How many screws do I need? The centerfire actions seem to all have 4, do I really need 4 screws for a rimfire? Also what size screws do I need? I would prefer them to be torx head, just not sure what size. I am planning on using the DIP 25 MOA scope bases modified, would there be a better choice? Any comments or suggestions are more than welcome! Please let the debate begin! Thanks guys!

 

[Erthal]

I intend to do the exactly the same with my CZ. I believe a 8-40 screws will do fine.

 

[BenY 2013]

Thank you I think I will use that size screw! Anyone else have any thoughts?

 

[MarinePMI]

8-40's will work, though 6-48 is the industry standard (8-40 will allow you to go up if for some reason you break a 6-48 screw or tap off in the hole).

How are you planning to D&T the receiver? Forster jig? Or just set up in a mill? Might be worth making your own version of the Forster (don't think they are made anymore, and they got ridiculously expensive before they stopped).

Depending on where you are locating the base(s), drill through the receiver should not be an issue...

 

[BenY 2013]

I just looked at that Forster jig, that would be extremely helpful, however that price is crazy! I may try and make something similar. I think I will most likely set it up in a mill! And drilling through the action would be much more simple than trying to go just a certain depth!

 

[cal50]

As long as you are not drilling into the chamber I always drill thru.

 

[MarinePMI]

I just looked at that Forster jig, that would be extremely helpful, however that price is crazy! I may try and make something similar. I think I will most likely set it up in a mill! And drilling through the action would be much more simple than trying to go just a certain depth!

Yeah, I bought one, way back, when they were still under $200 (though that was still a lot of coin back then). If you have V-blocks and jig that clamps to the bolt rails and hangs from the bottom (that is squared), you should be able to accomplish he same thing.

 

[BenY 2013]

Yeah, I bought one, way back, when they were still under $200 (though that was still a lot of coin back then). If you have V-blocks and jig that clamps to the bolt rails and hangs from the bottom (that is squared), you should be able to accomplish he same thing.

That's what I was thinking! I would love to be able to make something like this for the action screws!