Generally, the sling swivel stud. If your Harris has a picatinny attachment on it they make an adapter that goes on the stud.

 

which model 10/22 do you have? there are several available from Ruger with plastic stocks

show us a pic..

 

It's the basic carbine with black plastic stock. Looks like I can use a Huntpro stud.

 

Same as for the wood stock. I used the screw in stud