How bad is this bolt inteference?

Kelly Timoffee

Kelly Timoffee

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In the ongoing saga of my Vanguard woes....

How badly out of true would you say these lugs are?




Cycled 10 times empty and 10 times with a loaded round, not even a mark on the lower lug.

Is there even any point to truing up this thing?
 
Hmmm, the more you point out this firearms problems the harder it will be to sell on the EE. :p I guess winter is coming and if you need a project, this will be it. Personally if it was mine it would be gone.
 
I am thinking the design of two bolt lugs wants both to be doing some holding at lock up - I suppose in perfect world that is 100% contact, each? Hard to make anything perfect, but would be looking for some bearing by each lug? Also, if you coloured the rear of the lugs and closed the bolt, do not really know where the contact was being made? Imagine a ridge at in-feed edge of a recess - would scrape off the marker before the lug anywhere near closed? Maybe try partial closing for a few cycles to determine where that rub is really occurring? Not certain there is really a "fix" for uneven bearing? In older mausers with case hardening, not much thickness to the hardened skin, so any "lapping" tends to wear through and get setback reasonably shortly after. No idea how modern rifles like Vanguards are heat treated? Any "lapping" to recess (after pulling barrel) or to rear of lug can only increase headspace - may or may not still be within tolerance once you get them both in contact? Or will have to re-set the barrel?
 
If that were my rifle, I would lap the left lug in the pic to at least 60% contact.

I suspect you've done this before?? If not, use a very fine stone, very carefully to start.

It may actually be a problem with the lug seat in the receiver. You'll have to determine which component is the problem.

Some folks just use automotive valve lapping compound, such as cloverleaf brand, in the small green tins. To do this, you will need to apply the compound on the seat of the lug and work it up and down. Be sure to keep the bolt fully assembled so the spring give you rearward pressure against the offending faces.

It goes pretty fast, so be careful.

Good luck, you deserve it at this point.
 
I've never seen a Remington lugs that far from true... it's not unusual for the mass produced items to have tolerances out a bit but that looks as if it could be from 1/10000 to 5/1000 out. Usually one will have near 95% contact and the other anywhere from 20-90% contact and someone building a target rifle will have that trued along with several other points. Depending how far out that is, lapping that lug so the other engages might result in excess headspace. It looks like a deep gall already scratched out of the lug, I'd be suspicious of the lug recesses in the receiver as well or the primary issue.

disclaimer:I'm a tradesman in field other than machining/gunsmithing so naturally I defer to a specialist.
 
bearhunter said:
If that were my rifle, I would lap the left lug in the pic to at least 60% contact.

I suspect you've done this before?? If not, use a very fine stone, very carefully to start.

It may actually be a problem with the lug seat in the receiver. You'll have to determine which component is the problem.

Some folks just use automotive valve lapping compound, such as cloverleaf brand, in the small green tins. To do this, you will need to apply the compound on the seat of the lug and work it up and down. Be sure to keep the bolt fully assembled so the spring give you rearward pressure against the offending faces.

It goes pretty fast, so be careful.

Good luck, you deserve it at this point.
Click to expand...

Wouldn't that increase headspace ?

Grizz
 
Grizzly Adams said:
Wouldn't that increase headspace ?

Grizz
Click to expand...

Yes, it would but likely only by a few thousandths of an inch.

That condition on a bolt, isn't at all uncommon, even on some of the expensive custom jobs.

Usually it's one thing match shooters won't tolerate and it does seem to help with accuracy issues.

If you get a used rifle, and this condition is present on your bolt, the first thing you do is check the receiver lug seat surfaces for set back. Usually, you can feel it with your finger. If all is well, then lap the offending lug on the bolt.

It's been my experience with bolt lugs is that they are mostly HARD, all the way through.

The offset of the lugs, can contribute to accuracy issues, far more than an extra few thou of headspace.

To many people are paranoid about headspace. It isn't nearly the bugaboo it's made out to be, unless it's drastically over maximum.

This isn't rocket science. Keeping the bolt face square to the axis of the bore/chamber can only contribute to repeatable good accuracy.
 
New Camper said:
I've never seen a Remington lugs that far from true... it's not unusual for the mass produced items to have tolerances out a bit but that looks as if it could be from 1/10000 to 5/1000 out. Usually one will have near 95% contact and the other anywhere from 20-90% contact and someone building a target rifle will have that trued along with several other points. Depending how far out that is, lapping that lug so the other engages might result in excess headspace. It looks like a deep gall already scratched out of the lug, I'd be suspicious of the lug recesses in the receiver as well or the primary issue.

disclaimer:I'm a tradesman in field other than machining/gunsmithing so naturally I defer to a specialist.
Click to expand...


I have and I'm willing to bet guntech, tiriaq and Mbogo as well as a few others here have as well.

KT's bolt isn't that bad, but I don't believe it's the cause of the accuracy issues he's been having, if it's from the same rifle.
 
With respect to bolt lapping...
Years ago I made tools to do this.
To lap the locking abutments in the receiver, I turned a bar to smoothly fit the bolt way. Turned a chunk of cast iron to the diameter of the locking abutments, threaded it to the end of the rod. Random hacksaw cuts on the face of the cast iron lap, to carry the lapping compound. Before use, the unit is set up on the lathe and a light cut taken off the face of the lap, to guarantee that it is perpendicular to the receiver axis, and remove any wear from previous use. Compound is applied to the lap face, and the unit is inserted into the receiver from the front end. It is fitted to a drill, and pulled back against the abutments. Light pressure, checking frequently until the abutments are both cleanly faced. Clean the receiver, removing all traces of compound. Best to use a non-embedding compound.
OK, the receiver abutments are now trued up. Time for the bolt.
I made short sleeves which thread into different receiver rings. These are fitted with plungers used to apply a load directly against the bolt face, co-axially with the receiver bore. Compound is applied to the lugs, bolt is closed, pressure is applied to the bolt face, pushing it back against the abutments, and the bolt handle is raised and lowered. This procedure will fit the lugs to the abutments with proper alignment.
Can be done after the abutments and lugs have been machined true, if machining was necessary.
The point of using the tool to push the bolt straight back is to avoid any lateral loads while lapping.
Note that the barrel must be removed to do this work.
 
New Camper said:
Sorry, I was ambiguous in my statement... I know it's a Weatherby bolt: I was simply comparing it to Remington which in the eyes of some has suffered plenty of QC issues: Which is to imply that I would never have expected this in a Weatherby, even their economy line.
Click to expand...

It is possible that I did do something to this firearm albeit unintentional to cause this.
 
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