Before you take it apart, make sure the top lever is relaxed. I've never heard anyone state that it hurts anything when the pin is removed from the floor plate, but it makes a heck of a CANK noise without the lever spring relaxed. To relax the lever, look at where the barrel wedge fits, there is a little pin there. Push down on it while holding the lever, and you can gently relax the rotary bolt and lever.
Take the whole thing apart. I'm not a fan of drilling a hole in the stock after my custom clamp slipped just a bit and did this:
I made a tiny wedge of brass, and drilled a hole into it for some fishing line.
I compress the spring with the wedge, and after the whole thing is together, but before the sideplates are on, I move the lever to the right. This frees the brass wedge which can then be pulled out by the string. Just be sure the wedge will fit through the gap in the stock head and that the string is properly located during assembly. The benefit of this over the hardened pin/pry method, is that there is no chance of buggering the fine threads of the top lever. Best of luck to you.
Rob.
