I have been informed by several 'smiths that the pre-64 with a sr. number below 400,000 were well case hardened and actions could be made slick as you-know-what, but, actions with a higher sr.# were less hardened in order to make them tougher. Thus the newer ones cannot always be made as slick as the older ones.

Is this true?

One of My Mod. 70s is in the 500,000 area and the last 1" of the bolt draw is sticky and the two 'smiths have not really been able to do much about it.

Steve

I have quite a number of pre-64's varying from first year to last year of production. My experience has been that it depends upon the machining of the bolt and matching raceways. Some riles held vertically the bolt falls rearward easily within a few degree of becoming vertical. Others stay put but with a little wiggle they fall rearward. I would try lapping the bolt raceways with a little mild abrasive first. A couple of mine really show the milling marks and some are smooth a heck regardless of year of manufacture. I do know that the pre-war rear receivers are as hard as the hubs of hell when I drilled and tapped holes for mounts on guns I intended to shoot with scopes.

All of the real sticky M70s I have seen have been later ones. I suspect that this happens when in heat treating the bolt and reciever end up at approximately the same hardness and that a little on the soft side. When you have one of these you can polish forever and it will still be sticky. The worst one I had anything to do with would stick well enough that it would support my weight! this in spite of the fact that bolt and receiver were very smooth and lightly oiled In the end the cure for this one was to teflon coat the bolt. I think nitriding might work very well or one of the similar hard surfacing treatments. Regards, Bill.