Home Forums Hunting & Shooting Gunsmithing M70 hard cocking?

I have a brief M70 question. I just picked up a very slightly used stainless Classic 308. During sight-in today the rifle shot great (.5-.8 with the first factory load tried for 5 shots...) but encountered a problem after about 30 rounds (total of 40 fired).

After firing about 30 rounds, the bolt handle started becoming slightly difficult to lift. This occured as I switched from Hornady ammo to some surplus Austrailian Ball (shooting into about 1"). I suspected high pressure but the cases didn't show any signs. It got progressively worse until I quit shooting 10 rounds into the problem. My last 3 rounds were Hornady ammo again and the bolt lift was still pretty harsh so this sort of rules out the pressure issue since the Hornady ammo was fine for the first 30 rounds.

Upon inspection, I've got some significant galling on the cocking cam and there is an actual small groove worn into the camming surface. Is this normal in 40 rounds? Is this normal breaking in? Does any corrective action need to be taken (stoning, gunsmith, prayer)?

There were actually some very light metal shavings in the bolt shroud recess. After wiping it off and relubing it, it has smoothed up again. Could a lack of lubrication have caused this type of issue in 40 rounds---are they that sensitive? Any thoughts at all?

I touched up the camming surface with some light emery paper and it smooth ed out significantly but the gall/gouge is still there.

Before:







After touch up:

Yes, yes, and yes.

Anytime two metal surfaces rub against each other there needs to be a film of lube to break the surface tension. If not, this can happen, particularly with stainess steels. The cocking piece will have to be addressed as well as the camming surface. Don't try to remove the gouge, just make sure that the surface's match one another and are smooth and without snags. Use a good copper based lube like the stuff permatex sells. Use a little of this on the backs of the bolt lugs as well. Clean the surfaces good, first, to remove any foreign particles and abrasives.

http://www.permatex.com/documents/tds/Automotive/09128.pdf

I'm not sure that's galling. The divots are too evenly spaced. I have the same marks on a couple of blued steel M70's and believe it is where the bolt handle was pressed on.

Like Malm says, it's rather common in the SS models.. The cocking piece and bolt body will need to have those areas addressed or it will be a pita forever..

On all the M70s in SS I recommend also a small dab of a good grease (lithium based is fine) or even better would be a Moly-based product.. Use the same stuff on the bolt lugs.

I checked a few other M70s today at some of the local shops and the "divots" were somewhat evedent on all of them. I think they are probably a result of where the bolt handle was pressed on and the joint is peeking through.

By "addressed" does that mean a gunsmith trip or simply a bit of further polishing it out with emery cloth followed with a good lube? Would more initial lube have prevented this completely or is this just one of those things that is eventually going to happen on SS M70s and I just need to live with the gouges (which bug the hell out of me...)?

In this case, "Addressed" means dealt with. If you can polish the area without changing the angle of the ramp, then go for it. A good high quality lubricant will keep things from galling. It reduces friction which leads to damage.