What Would Cause This?

[KLR]

I bought a new barrel and made a chamber cast.

Here's how it looks. Any idea of what caused this? The pictures are of opposite sides of the chamber cast.






I have an idea of what caused this, but would like to hear from some of you guys who have more experience.

BTW, I sent the barrel back and got a full refund. I'm not trying to flame a vendor. Everyone makes mistakes and I'm figuring this was an isolated incident.

[swheeler]

A chamber cut not concentric to the bore, big time. The pilot must have been way undersized.

[vzerone]

I'd like to know who you bought the barrel from and I would have to agree with swheeler.

[KLR]

A chamber cut not concentric to the bore, big time. The pilot must have been way undersized.

I wonder if a chip wedged under one side of an undersized pilot.

[Biggin]

Off topic but does KEL stand for KLR650?

[Biggin]

Sorry spell check Klr

[country gent]

It could be an off centered chamber or one not cut parallel to the bore. How does it measure round or egg shaped? measure with good mics at 90* at one point. Another is how are the dimensions as to specs. If large then it may have been a tail stock out of alighnment also. I'm curious as to how it was cut and the set up. Centered in 4 jaw and spider at back end. unsupported at muzzle, collet or center and steady rest?

[KLR]

KLR650 -
I had one when I registered here.

[ascast]

bad pilot - ing or "cut rifling"? not right. Can you spin the casting in a concentricity gauge? If the rifling is correct, I think you should be able to see the "OFF PILOT" bend angle with the nekked eye and straight edge.

[Biggin]

Had I hate to hear that. I keep one around to scratch the itch when I can.

[KLR]

1. Neck of case measures round.

2. I used a straight edge and a stack of feeler gauges and the cartridge and bore are at an angle.

3. I have a DR650 now to scratch the itch.

[ascast]

DR650 ? What is the joke?

[Hannibal]

Chamber was not cut concentric to the barrel bore. Got one like that about 6 mo ago myself. Caught mine with a borescope.
It's a tomato stake. No fixing that problem aside from cutting the stub off and rechambering it.

[KLR]

DR650 ? What is the joke?

Sorry. Off-topic reply to an off-topic question. It's about motorcycles.

Chamber was not cut concentric to the barrel bore. Got one like that about 6 mo ago myself. Caught mine with a borescope.
It's a tomato stake. No fixing that problem aside from cutting the stub off and rechambering it.

I didn't figure there was any way to fix it, so I returned it. I have a bore scope and will be scoping every new barrel I get from now on out.

[Hannibal]

Sorry. Off-topic reply to an off-topic question. It's about motorcycles.




I didn't figure there was any way to fix it, so I returned it. I have a bore scope and will be scoping every new barrel I get from now on out.

Yep. I bought mine to check for serious barrel defects and to monitor my cleaning processes. It's already saved me a bunch of trouble.

[ascast]

you going to share who did this? sounds like I'd want mine done elsewhere. just sayin

[John Taylor]

Took a barrel off a 50 BMG single shot that had the chamber not lined up with the bore. It was bad enough that it could be seen looking down the bore from the chamber end.

[john.k]

This is an extreme example,but the eccentric chamber is not uncommon with some bigname rifles,and when cheap USB cams came in there was a stream of returns when owners spotted the uneven cone of the rifling lead.The manufacturers reply was "we have shot your rifle,and accuracy is within limits for calibre.....and you will bear the cost of any further investigation"......The cause of the effect is the chamber is not reamed,but CNC bored with a single point tool.....hence if the barrel does not rotate on the bore axis,the chamber will be eccentric.

[Cap'n Morgan]

"The cause of the effect is the chamber is not reamed,but CNC bored with a single point tool.....hence if the barrel does not rotate on the bore axis,the chamber will be eccentric."

Now that explains a lot! I couldn't believe it would be possible to offset a chamber that much with a reamer - unless no pilot was used. Using a single point tool is to ask for trouble. Even if the bore is clocked at the start of the chamber you have no way of knowing if it's still running true three inches into the barrel.

[KLR]

It must be rocket science to make a good AR barrel.

I ordered another barrel, in different caliber, from a different manufacturer and it also has a crooked chamber.








Both vendors gave a full refund and paid return shipping.

But it's still aggravating.

Hopefully sharing my experience will help convince someone to check their barrel carefully before spending a lot of time and money putting together a rifle with a crappy barrel.