Repairing pitted boltfaces

Hi gents,
I have a rem 700 and two sako L461 actions with pitted boltfaces I intend to rebarrel within the next couple of weeks.
Is there anyone out there an opinion on the maximum tolerance for the Bolt face to back of the extractor dimension before extraction starts to play up.?
I'm guessing this will vary between makes and models.
JB

Are you asking how much you can face off to remove the pits? I know some people would TIG weld the pits and face back to the nominal dimensions. This can be done with quick welds and complete cooling between welds so you don't ruin the heat treatment.

GGaskill said:

Are you asking how much you can face off to remove the pits? I know some people would TIG weld the pits and face back to the nominal dimensions. This can be done with quick welds and complete cooling between welds so you don't ruin the heat treatment.

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Yeah, Obviously removal of metal from the boltface will have an effect on extraction to some degree and thought that there may be a rule of thumb in relation to how much metal can or should be removed before boring out and rebushing and redrilling etc.
I had thought about the pros and cons of Tig welding and may go down that path.
Thanks.

PS. I suppose another way to ask the question would be to ask what extractor to cartridge rim clearances are acceptable?

Genreally speaking taking a couple, three thousandths off is no big deal. You can take far more than that off before the extractor begins to be a concern as it will ride up the case. The problem is that as you do it and correct headspace you get more case head protrusion and that can be a bad thing. I think if you get more than the standard .150 head protrusion you are getting into that grey area where you are moving up on the web of the case to much. With the Sako its no big deal because you can face off the nose of the bolt a bit and set the barrel back the same amount. With the Remington you can't do this without installing a Sako or the like extractor. There simply is not enough material on the nose of the bolt with the Remington extractor. Like GGaskill says you can TIG up the face if you are careful and with the Remingtons it's not a problem. The bolts won't go hard and if something goes wrong you can always find another bolt or buy a PTG. I do know from welding on handles that Sako uses some form of Zimbabwe death steel in their bolts and they do like to go hard when you weld them. Also, I'm not sure what its like in the land of hoppy go bangs and drop bears but over here in the land of ice and snow, provable, Sako parts can be very hard to get should the need arise. Best to always check the depth of the water before jumping in. Govern yourself accordingly, I guess.

ADD NOTE: You can always knock about .020 inch off the nose of the Sako extractor if it hits the face of the barrel and re-sculpture the cam/feed taper on it. That's been done to death.

how about bushing the boltface?

quasi said:

how about bushing the boltface?

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+1

Thats been done all the way back to the paleolithic era and works well too. Much less risk than welding too.

Just curious if anyone with a CNC mill had ever done this to fill a bolt face.

(1) Cut an undercut circle in the face with a small 60 degree cutter.

(2) Cut a corresponding undersized plug out of annealed CS70, CS80 or CS95.

(3) Coat both parts with a fluxed tin solder paste and peen the plug to fill the undercut the same way an engraver does to expand and seat the plug.

(4) Drill the firing pin hole and face it off.

(5) Heat to solder and lightly harden and toughen the spring steel plate.

Clear as mud?

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

Seems like it would be difficult to get the fill piece hot enough to harden without annealing the rest of the bolt head.

Shouldn't be that difficult to do conventionally with a rotary table.

GGaskill said:

Seems like it would be difficult to get the fill piece hot enough to harden without annealing the rest of the bolt head.

Shouldn't be that difficult to do conventionally with a rotary table.

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Yeah, tin solder flows at a pretty low temperature so it probably wouldn't harden the spring steel much if at all but a guy could spot heat treat it in a couple seconds by sticking a copper plug in the firing pin hole and hitting the wafer with the TIG and it wouldn't heat the main bolt body at all. But then again it does not have to be hard anyway so it's sort of a pointless issue.

The bolt handle wont go in a conventional chuck but you're right, a guy could clamp a big V block or L block to the rotary table and center it up and do it. It always seamed like a big operation to do it conventionally so I have never tried it. Not to say it hasn't been in the back of my head and eating a hole in my skull for 15 or 20 years though. I may have to try it once just so that I can sleep at night. LOL

It sure would be a slick, simple way to do it if one had a CNC or even one of the small Tormachs that 300sniper plays with. Clamp it in, in center it up and turn it loose for 30 seconds. Whether or not the plug would peen in OK is probably the part that worries me most.

Back in the early seventies, Remington had quite a bit of trouble with their primers blowing and pitting bolt faces. This happened to me, and Remington had me send the rifle (Sako L579 in .243) in to them for repairs. What they did was recess the bolt face and hard chrome it back to size. The fix has held up for more than 30 years, so I guess I would go that route as it has stood the test of time and a couple thousand rounds and it still looks like new....

Johnny V
NRA Endowment Life Member

It's somehow refreshing in a morbid sort of way, to know that even the big kids have trouble getting provable parts like bolts out of those frost bitten reindeer jockeys in Finland.

Johnny V said:

Back in the early seventies, Remington had quite a bit of trouble with their primers blowing and pitting bolt faces. This happened to me, and Remington had me send the rifle (Sako L579 in .243) in to them for repairs. What they did was recess the bolt face and hard chrome it back to size. The fix has held up for more than 30 years, so I guess I would go that route as it has stood the test of time and a couple thousand rounds and it still looks like new....

Johnny V
NRA Endowment Life Member

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Would that problem have been in relation to copper instead of brass primers. Thats what some blokes down here blame it on.

Don't really remember what the problem was caused from, but Remington stood behind their reloading components and repaired the bolt. I vaguely recall something about the primer metal, but it was way too many years ago, and the memory just isn't what it used to be........

Johnny V
NRA Endowment Life Member

Gas cutting from primer leakage or failure is not as prevalent today as it was back in the 1960s though it still does crop up from time to time. From my time doing warranty I was told that there has never been one, quint essential reason for it other than the simple fact that gas finds its way around or through the primer. The main reason is inconsistency in the hardness of the primer cups, the case itself and dimensional problems. If there are dimensional problems and the two components do not fit properly its like a stopper that's two small for the drain and water gets by. If primer cups are to soft the indent made by the firing pin can "manhole cover" and follow the firing pin back into the port in the bolt. If it is to hard the firing pin can punch right through. If the cup is to hard it can also fail to obdurate and seal itself in the primer pocket. If the brass itself is to soft it can expand and the primer cup will not be able to expand enough to catch up and seal it. Most people that have done warranty for the major manufactures have noticed that neither Browning or Remington make mention of the problem in their field service manuals. Over the years they have gotten the problem fixed to the point that it seldom crops up and like many other problems it's one that they have chosen to sweep under the carpet and forget about.