Bad Shilen barrel ?

Sorry guys. I was using the (.00001) term figuratively.

Thanks again, I learned something.

I thought I had a high dollar tomato stake!
 
From Shilen

"Select Match Grade
These stainless steel masterpieces of machining and hand lapping are intended for the competition shooter-- or even the hunter-- who wants the ultimate in accuracy and quality. These are our highest grade barrel and, of course, the most costly. What makes them so good that benchrest shooters, such as Tony Boyer, crave them? Consider this: To meet Select Match Grade criteria, the groove diameter must air gauge within .0003" of our standard diameter. Moreover, the uniformity of the bore cannot vary more than .0001" for the entire length of the barrel. These barrels are also completely stress relieved, and the bore is polished to a gleaming surface finish by our most experienced lappers."
 
Originally Posted By: ninehorsesIn his defense, My gunsmith is a .00001 type of guy. That's why I use him.

I've got $4,000 worth of measuring tools in my box, and none of them will measure .00001".

I've worked to +/- .0002" boring precision holes, but you won't see that on a gun drilled barrel. Maybe if you EDM'ed one full length, but you couldn't afford the finished product.

But if he says that's the worst one he's ever seen, Shilen is doing something right.

Taking a .004" finish cut to true it up wouldn't even be noticible without a mictometer, that's a human hair thickness, or a sheet of notebook paper.
 
Originally Posted By: calling4lifeFrom Shilen

"Select Match Grade
These stainless steel masterpieces of machining and hand lapping are intended for the competition shooter-- or even the hunter-- who wants the ultimate in accuracy and quality. These are our highest grade barrel and, of course, the most costly. What makes them so good that benchrest shooters, such as Tony Boyer, crave them? Consider this: To meet Select Match Grade criteria, the groove diameter must air gauge within .0003" of our standard diameter. Moreover, the uniformity of the bore cannot vary more than .0001" for the entire length of the barrel. These barrels are also completely stress relieved, and the bore is polished to a gleaming surface finish by our most experienced lappers."

That's bore diameter, it's cut with a precision carbide button or a pull broach, then hand lapped.
That does make a difference if it's not uniform and on-size.

The outside diameter, not so much.
 
A bore being .004 off center is nothing. I have see lots .050 or more off center.

Jack

I agree with Jack. I built a 22-250 A.I. and used a Shilen #7 SS Select Match barrel that the center of the bore wasn't even close to the center of the barrel but it still shot great. 2's and 3's were the norm at 100 yards and I shot several groups well under 2" at 550 yards. Although it was definitely strange to look at!
 
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