Bent Barrel?

[smithbrl]

I got a Remington take off barrel in .243 that I want to install on my Mexican action. While I was checking it out I put it between centers on my lathe. I rotated it and using a dial test indicator I found it had varying "wobble". Near the muzzle the indicator barely moved (about .001). Near the middle it moved .014 and at the breech it was .011.

 

I don't know if it is just the outside machining or if the barrel is bent. The barrel appears new inside and out. How can I check the bore to see if it is straight? If it is bent I don't suppose it can be easily straightened but I thought I'd ask. Any ideas?

 

Thanks

Cecil

[BobVZ]

You can use the old shadow line method to check for straightness. Clean the barrel and lightly oil so that it reflects light like a mirror. Set the barrel up on sandbags or V-blocks about 6-10 feet away from a light-colored interior wall in your home or shop. A light, flat latex painted wall is ideal. Take a yardstick and paint it black. Hang it on the wall. Sight thru the bore and center the yardstick. Move your head up and down till you see the shadow line cast by the yardstick from muzzle to breech. If the shadow line is straight, that means your barrel is straight. If it is bent or worse broken, you have a bent barrel. Sometimes if it just a slight bend it may shoot ok. The bend is at the spot where the line is bent. Rotate the barrel 90 degrees and check till you go thru 360 degrees.

[z1r]

I doubt it is bent. Are the threads true or are they also out by .011"? I've recut enough of these rem takeoffs to tell you what you are seeing is about the norm. Which is why they tell you always indicate off the bore not the barrel (exterior).

[smithbrl]

Bob

I tried the shadow method but without knowing exactly what to look for, I'm still not sure. I saw the line but it did not look like it ran the entire length of the barrel. Maybe I didn't do it right.

 

Thanks

Cecil

 

Z1R

I checked the threads and the indicator shows .011 runout on them. What does that mean?

 

Thanks

Cecil

[BobVZ]

Bob

I tried the shadow method but without knowing exactly what to look for, I'm still not sure. I saw the line but it did not look like it ran the entire length of the barrel. Maybe I didn't do it right.

 

Thanks

Cecil

 

Cecil,

 

Start with your eye below the breech and the bore not visible. Raise your head slowly until the bore starts to become visible. Just as you see light at the muzzle, the line should appear from breech to muzzle. If you raise your head too much it will cut off the line. Seeing the line is very sensitive to head position. Its kinda like learning to whistle - once you get it, you've got it!

 

 

Bob

 

[z1r]

Z1R

I checked the threads and the indicator shows .011 runout on them. What does that mean?

 

Thanks

Cecil

8694[/snapback]

 

 

This depends on how you arrived at the number. Did you dial in the bore with a range rod? If so, and you had that much runout, then you have a barrel with a poor chambering/threading job.