Galled lug... grrrr

[coreydelong]

Noticed today my SA 700 has a gall mark on one of the lugs. I have religiously greased the bolt and cleaned/oiled very well.

My local shop owner says he see's more Remington bolts with poor quality as time goes on. He has a fewNIB bolts right in the store that look like they were kicked down a gravel road before they shipped out.

Wondering if I should bother sending it back, or just getting a PTG bolt?? I don't want a new POS back from Remington thats gonna fail down the road again.

 

[Kings X]

The action maybe galled also. Putting a new PTG bolt in a bad action is a bad idea.
Take some fine valve lapping compound and work both lugs in. You may have to file the build-up off that lug. Don't worry you cannot hand lap enough to effect headspace.
Be sure to use a grease with high pressure moly.
Money well spend is to replace the whole firing pin assembly.

 

[jonbearman]

Tell us the caliber and what loads you have worked up because if it galled that bad,it sounds like over pressure to me.

 

[Minesweeper3433]

On the subject of galled lugs, are the lugs through hardened or are the surface hardened like an old mauser action? I only ask as i did the same thing and in order to keep from having to adjust my headspace on the barrel after relapping the lugs me and my smith decided to relap only to get rid of the material that had built up. The scratch is still there but my headspace hasn't changed and I have a reminder to use proper lubricant on them forever now.

 

[ChrisNZ]

.. if it galled that bad,it sounds like over pressure to me.

Inadequately sized cases and no lube can def do it without overloads.
Doesn't sound in this case a total lack of lube was the cause.

Chris-NZ

 

[coreydelong]

I will fess up on this one.... totally my fault. The galling was not bad at all. One skinny hairline mark on the bottom lug that cleaned up nicely with a stone.

After some investigation last night I discovered that the front action bolt was the culprit. There was no issue on initial installation to a B&C Medalist Stock (#2094). After a few hundred rounds I believe I checked the torque and then I just noticed this problem.... again it is so slight that I noticed ZERO resistance closing the bolt. I probably would not have noticed the mark if the bolt was not blued to begin with. Thats how slight it was.

After I cleaned the lug up I put a shim under each the front and rear action bolts and there is no evidence of any contact at all now. The rifle came with no shims and there were no issues before I re-checked the torque to 45in/lb as recommended (thats on the low side). The bolt feels no different and she put up a 1.090" group at 325yds today..... 0.335 MOA. I'll take it. She's just my plinker anyways. I felt so good about her today I ordered a Jewell trigger from Larry to replace this X-Pro POS that came on it.

 

[Kings X]

"are the lugs through hardened or are the surface hardened like an old mauser action"
You might be suprised to find out the hardness of commerical actions today. They are softer than you might think. It has been awhile since I checked any, but 25 Rc sticks in my head.
Simple test - try filing one. They cut with ease. And both action and bolt are the same material and hardness, No wonder they gall.
Lapping rarely removes more than .001". That is not enough to effect headspace.
BUT ONCE LAPPED - you have to keep them greased due to increased contact surface.

 

[Minesweeper3433]

Thanks kings x. The rifle is a 300 winmag with the headspace set at 0.001 longer than 0 headspace. I have a factory rem700SA that I installed a used 308 barrel I picked up here on and the headspace was actually negative .001 once torqued into place. I just put up with the tight factory ammo and set me sizing die down all the way.

 

[lpreddick]

a slight aside...the lug recess area get REALLY DIRTY. any grit left here might damage the lugs. i use the sinclair lug recess cleaning tool every time i clean and there is always crud/nasty stuff there. lug grease is definitely a must do after every cleaning. no question remington's quality is down. my gunsmith, a former remington gunsmith, tell me he hate seeing a remy brought in for a build. he tell the owner he'll have to give it the "works" if he hopes it will shoot and even then he's not optimistic.

 

[Robert]

.. if it galled that bad,it sounds like over pressure to me.

Inadequately sized cases and no lube can def do it without overloads.
Doesn't sound in this case a total lack of lube was the cause.

Chris-NZ

Chris,

Overpressure probably not, as, on firing, the lugs are fully engaged on total bearing surface with no motion in a static role.

The problem happens when the bolt is rotated and bears on a small surface to start the closing when the bolt is used as a sizing press or when attempting to open after an overpressure..More often on closing than on opening anyway.

Having said this, magnum bolts heads have 25% more surface than a .308 and total pressure is in relation and this could be marginal for small lugs bearing areas and soft receivers material: abrasive particules inprint in the softer surface to 'eat' in the harder...For this reason, laps are always made from soft material.
Ideally, bolt and receivers should be same herdness at contact points.

Tha 25 HRC mentionned correspond to some 240 Brinell, which is the hardness of 4140 in natural or annealed condition......Quality requested for making a good lap..LOL.
R.G.C

 

[Raptor]

Intresting that you had the same problem that I did. I didn't have the galled lug but my accuracy went to hell after I had put the barrel on a long action. When it was on a short action my 284 was and absolute hammer!! After switching it to a long action and putting it in a different stock the accuracy went to hell and the rifle was very inconsistant.

I thought it was brass at first then when I was out shooting a couple of weeks ago I shot a group with it to check the zero and it was more of a pattern.

I was pissed and when I put the last round in I was trying to hold my temper and instead of slamming the bolt down like I wanted to I just held my temper and closed it very slowly counting to 10.(HA)

When I did this I noticed a slight click as the bolt closed so I opened and closed it again at regular speed and did not notice it, closed it slow and could feel it again. Took the round out closed it normal and slow several times could not feel it. Put a round in close it slow and I could once again just feel it catch. I loosened the front action screw and could not feel it again. So I pulled the screw and ground it down a thread or so and the rifle went back to shooting .3s again!!

I would not have believed it if I had not of experienced it. Now the rifle is a hammer again. Just because of very slight contact with the action screw I spent countless hrs and rounds trying to figure out what the hell had gone wrong!!

 

[Wrangler John]

Remingtons need that screw to be checked after torquing them to specification. The screw should be flush with the floor of the lug recess when properly torqued. Grinding to length is better than shims. Just changing the torque on the front and rear screw can blow groups out or shrink them. I experiment with various action screw torque settings until the groups become as small as they will, then begin to open with additional torque. Requires a torque gauge or torque wrench. My stocks are all pillar bedded or have bedding blocks, so torque settings are higher than factory wood. This is true of any bolt action rifle.

Also be certain that the magazine box is free when the action is tight. If the action clamps down on the magazine box and floor plate, that will make accuracy suffer. Only requires a little clearance, just enough for it to move.

Another thing that can blow groups apart is the front screw of a front scope base. If it bottoms out on the barrel threads before it tightens against the base groups will suffer.