Is my barrel screwed on crooked?!!

[Tesoro]

Ok here we go: I have a Kelbly Atlas with a pinned picatinny rail installed by them. No question as to the alignment of the rail to the receiver. I have a 28in Kreiger m24 6mm barrel. I ordered a new March scope with a set of 34mm Burris xtr 3 screw rings with the inserts. My plan was to set up this scope to maintain as much optical center alignment at 1000 using the inserts.

However on setup, with the reticle being centered, the scope's horizonal alignment was off 17 moa to the right at 40 yd boresight! The scope has 40moa total horizontal travel so I was nearly bottomed out to the left. I r/r'd the rings from the base 2x and same result. Initially I had set zero inserts on the front and rear rings. I also tried +/- 5 &10 moa inserts and same thing - way to the left.

I then reset the scopes horizontal travel back to center and was able to align the scope and bore onto target at 40 yds by installing 10moa inserts at 45 degrees, ie the fat and thin parts were opposing at 9 and 3 o'clock.

I just took it to my 100 yd spot for zero and was only off a few inches to left from the boresight adjustment. I then calculated dope and shot it at 1000 and horizontal was fine.

The last scope I mounted was a NF 12-42 which also has 40 moa horizontal. I didnt pay as much attention to optical center that time but I do remember having to dial quite a bit on horizontal to get on paper.

So what gives?

I cant imagine Kreiger shipping out a barrel with the bore that much out of alignment with the tube, and I am ruling out March and the rail. Is it possible my chamber job is excessively out of alignment with the bore? Curious! But no matter what it is shooting straight and accurate.

 

[Walt Krafft]

Remove the barrel. Clean all surfaces. Check for burrs or bumps and remove. Reassemble and check again. A very small burr or piece of crud can make a big difference,

 

[jackieschmidt]

^^^^^^^
This is the first step.

If everything looks good, then the barrel might be the culprit.

Who was the Gun Smith. If he used the “Gordy Method” of setting up the barrel,, there is the possibility that the first portion of the barrel was quite a bit out with the rest of the blank. Truing that part to chamber could result in the barrel pointing quite a bit off.

I have personally seen blanks exhibit this very phenomina.

Of course, “clocking” the barrel so it points up would cure this. Having to do this is a product of that particular method of truing barrels when you do the chamber and tenon.

 

[DaveTooley]

How do you set up a barrel for chambering?

I just did a refresh on a pair of LE rifles. Complete disassembly. Down to individual parts. New barrels, Cerakote, assembly. I always shoot these LE guns some to make sure there's not a problem. Just for the hell of it I never bore sighted either. First shot out of the first rifle was .7 Mil high and .5 left. Second rifle was 1 Mil left. Kind of surprised they were that close considering I cut 6" off the blanks after chambering. I remember the bore on one being slightly off center when I indicated it in for muzzle threading. That could account for the 1 Mil shift.

 

[Tesoro]

Ok thanks. I have had the bbl off once since new. I didnt see anything when I re-installed but will try that. But as I just mounted new scope and having fun I will wait a bit! It is shooting straight!
I will have to ask the fellow who chambered it as to the technique. But it is bothersome as something isnt right and I dwell on those things!!

 

[Walt Krafft]

Try a different set of rings without the inserts.

 

[jackieschmidt]

Dave, I always keep the throat and the ID of the muzzle true with each other. Of course, the chamber, the tenon and barrel shoulder are true with the throat.

There is certainly nothing wrong with using the Gordy method of truing a blank for chambering. The late Gene Bukys used a method similar to it. I had seen him change a barrel at the range and it print 4 inches from the one before at 100 yards.

But he won just about everything there was to win in Benchrest

 

[DaveTooley]

Dave, I always keep the throat and the ID of the muzzle true with each other. Of course, the chamber, the tenon and barrel shoulder are true with the throat.

There is certainly nothing wrong with using the Gordy method of truing a blank for chambering. The late Gene Bukys used a method similar to it. I had seen him change a barrel at the range and it print. 4 inches from the one before at 100 yards.

But he won just about everything there was to win in Benchrest

Lot of ways to do it. Concentricity is the primary objective.

 

[AlNyhus]

Ok thanks. I have had the bbl off once since new. I didnt see anything when I re-installed but will try that.

When you get the barrel off, gently tap the lug off and clean the mating surfaces. I've seen one instance where the barrel must have been just barely on when the bedding got done (not my bedding job ). Pulled the barrel on it, removed the lug and found what looked like a small speck of Plastigage in one spot. A tiny bit of bedding compound evidently got squeezed up between the lug and the receiver face in one spot.

Before removing the material, I put the barrel back on and you could definitely feel it didn't lock up instantly when it came up to the lug. After cleaning the lug, it snapped up like a bank vault.

 

[Tesoro]

When you get the barrel off, gently tap the lug off and clean the mating surfaces. I've seen one instance where the barrel must have been just barely on when the bedding got done (not my bedding job ). Pulled the barrel on it, removed the lug and found what looked like a small speck of Plastigage in one spot. A tiny bit of bedding compound evidently got squeezed up between the lug and the receiver face in one spot.

Before removing the material, I put the barrel back on and you could definitely feel it didn't lock up instantly when it came up to the lug. After cleaning the lug, it snapped up like a bank vault.

I was thinking about this last night and no my barrel is clean. When I put it back on I cleaned the threads and the lug very well and then greased threads with the goop kelbly supplied and it screwed on smoothly like a fine threaded bolt. There is no chunk of grit stuck in there, or burr, that points my barrel 16in off center at 40 yds.

 

[J_idaho]

Try a different set of rings without the inserts.

Inserts