The Pre-64 M70 I picked up had all the bolt parts disassembled by the gunsmith the previous owner was going to get the action nickel plated by. This rifle had sat for 15 years in the previous owners gunsafe before finally deciding to sell it.

Anyway, I noticed that when I went to put the bolt back together, the bolt shroud only screws in a short way back into the bolt (maybe half a turn). I cannot turn it in any further by hand.

Also is the cocking piece on the very back of the firing pin threaded on? If not, how do you pass the firing pin assembly through the centre of the bolt shroud (it has a flat machined into it, which corresponds to a ridge in the top right hand of the hole in the centre of the bolt shroud.

Any thoughts?

Strange. Sounds like some interference in the threads. Would probably benefit from lapping the two together. As for the flat, that is for the screw that supposedly keeps the bolt from flying into your eye if it separates. By the way, you can't slip the firing pin into the shroud with that screw in place.

Maybe this will help, worth a shot.

I just put a new firing pin spring on a post 64. I had the safety in the middle position and it would not thread back on all the way. I moved the safety to the fire position releasing the tension on the spring and I was able to thread it back on into the correct position. At points during the rethread I met some resistance but I was able to thread it back with just my hands. Then I put the bolt back into the rifle and cycled the bolt. Good as new.

I did just experienced something similar, but I attributed it to the spring rubbing on the inside of the bolt.