Home Forums Hunting & Shooting Gunsmithing Bolt Lug Galling???

Hi Guys, Just noticed what MIGHT be the beginning of very slight galling on one bolt lug of a nice used bolt action I picked up.I greased the lugs and ran the bolt for a while to see if it got any worse and it didn't, it is VERY slight.Any suggestions?? Leave it alone or would you do something with it?

Stainless action? If it were mine, I'd first check headspace to see if I had a thou or so leeway and go a brief lug lap.. Then ensure a dollop of grease is always present on each lug thereafter..

You might clean the insides of your actions. Use a cotton dental roll pushed through a hole you drilled in a wood dowel.

For lube grease with a moly it will resist galling better than grease without it. Use a grease made with a synthetic oil.

Thanks for the reply"s Guys! It's an FN commercial mauser action and I use Montana Xtreme grease, also the action has been cleaned.

This slight galling might have been there since the rifle was new, no telling. If it were my rifle, I would keep the lugs lightly greased and watch it for changes.

Look carefully at the metal behind the split lug for possible cracks. I have seen more than one FN with such cracks from being run too hot. The ones I have seen were obvious to the naked eye, but if it was me I would look into an X-ray or other NDT.

Thanks Guys! Left lug looks as new as does bolt face. Rifle looks pretty close to new. Galling on right lug is extremely minor.It only shows very slightly at bottom of right lug, I also wondered if it was from the initial machining???

Since it's apparently very minor, I'd go with moly grease applied and leave it alone..

wiktor,

If your FN is chrome moly, I would be surprised if the metal contact is producing galling. On stainless steel like metal contacts galling results from the surfaces "sticking", and you can even pull bits of metal away when you break the contact. I first learned about such behavior with 416SS in reactor plant piping systems in the 60s.

Perhaps you are seeing some wear in on that lug surface. I use a bit of several different greases on bolt cocking and locking surfaces, I can't tell that one is better than another.

I would use grease as the others suggest, and keep an eye on it. The FN actions I have seen with damage were the result of rechamber jobs that ended up with too much bolt thrust.

jim

Sitka deer,

Xray examinations are not particularly good at identifying fine cracks. The strength of Xray examinations lie in determining subsurface discontinuities. It take a good technician to properly develop the film and the orientation has to be just right to typically see indications (cracks).

For most cracking the traditional NDT (non destructive testing) method is magnetic particle testing (MT) for ferretic metals and dye penetrant testing (PT) for austenetic or ferretic steels. For PT the indication must be open to surface. It may be far to small to see visually but it must allow the dye to be drawn into the indication by capillary action. MT will detect some subsurface discontinuities (cracks) but they must be very shallow. DC mag partical units have a much greater penetrating depth but the AC units are usually hand held and portable. In either case make sure that person performing the testing is credible. Interpretation of the results is paramount.

Sorry if I bored anyone to tears.

It could be that the two lugs are not bearing evenly against the shoulders inside the receiver.

FN commercial actions are, I think, pretty hard and were machined to close tolerences. One possibility is that a too high pressure load might have been fired in it and either the lug or shoulder set back. You might want to have the headspace checked.

From your description I wouldn't even worry about it...If it gets worse then take it to a gunsmith and get it fixed, but most guns show a little wear in that area, and it's not really galling, they just take a fit.

Is the other lug making solid contact?

Thanks for the reply's!Yes, both lugs are making solid contact and gun does not appear in any way to have fired hot loads, or many rounds at all.Thanks!