Gunsmithing Sets screws

[BasraBoy]

Sorry if this a really stupid question......

I'm thinking about replacing my front sight/gas block on an AR with a low profile verion.

The existing assembly is a clamp on but I'd like to change to a set screw version.

Should the set screw detents on the barrel be threaded or are they just recessed for the head of the set screw?

Is there a standard size for these set screws?

Thanks in advance....

 

[kreiert]

Re: Sets screws

If the screws are up from the bottom of the gas block assembly you can get away with doing nothing to the barrel, if you have access to a milling machine a small flat is a nice touch.
From the side of the block, will require flats be milled for the set screws, to insure a no wind zero can be set.

 

[BasraBoy]

Re: Sets screws

Thanks kreiert

All the screws would be from the bottom.

But as far as I can find out the Douglas barrel has the dimples/detents in it for the gas block and Ops Inc collar as standard? Does anybody know if this is this correct?

 

[kreiert]

Re: Sets screws

It depends on who machined the barrel. Usually on the bottom 180 degrees from the gas port there is a dimple. This is used to help you get the gas port aligned with the block.