Cleaning up existing chambers

[Mram10us]

I don't know why any gunsmith would bother to try a re-chamber on a factory (Win., Rem., Howa, Savage, etc) barrel. It's just not worth the time or effort involved. Just cleaning one up, to make certain no carbon remains, can take a fair amount of time. Running a chambering reamer into a barrel that has some carbon deposits can dull the reamer. Rem. , Win., Howa barrels are hammer forged. The chamber is "roughed-in" as part of the hammer forging process. That's how you get a chamber that's 'crooked' (and a barrel that's crooked, too). A good custom barrel may be a good candidate for re-chambering. Each will have to make their own determination as to whether it's worth while, or not.

I had no idea the hammer forging was involved in the chambering process. I assumed it was reamed. Always learning something new. Thanks

 

[tobnpr]

Exactly what I said above. You can get a chamber that is maybe oval, but how can a piloted reamer cut a chamber that is off center from the bore?

Yeah, I'm still not seeing it- the condition obviously exists because we've all seen pictures of these situations where the start of the rifling cut is horribly crooked and would no doubt affect the straight entry of the bullet into the bore- and accuracy. But that small area directly behind the pilot that cuts the end of the freebore, can't be anything but directly in line with the pilot and presumably, the bore. I can't see how it could happen even with a cutter that has defective geometry.

Only way I can see it is extremely sloppy fit of pilot to bore, which would also cause chatter and a horribly "eggcentric" chamber.

 

[Mram10us]

Yeah, I'm still not seeing it- the condition obviously exists because we've all seen pictures of these situations where the start of the rifling cut is horribly crooked and would no doubt affect the straight entry of the bullet into the bore- and accuracy. But that small area directly behind the pilot that cuts the end of the freebore, can't be anything but directly in line with the pilot and presumably, the bore. I can't see how it could happen even with a cutter that has defective geometry.

Only way I can see it is extremely sloppy fit of pilot to bore, which would also cause chatter and a horribly "eggcentric" chamber.

Preach!

 

[Edd]

Gun Barrel Chamber Reamer Tools HSS | eBay

It is not marked, see drawing attached with photo. Size is as follows.

www.ebay.com

 

[shortgrass]

Its not the chamber that's crooked, it's poor bore and rifling. Not all lands and grooves are equal in measurement, which means if a land is taller on one side than on the other, the throat of the reamer will have more steel to cut on the "high side" than on the "low side". Which will give the odd, crooked appearance. Production made barrels are just not made with the individual care that custom, after market barrels are.

 

[MNbogboy]

Its not the chamber that's crooked, it's poor bore and rifling. Not all lands and grooves are equal in measurement, which means if a land is taller on one side than on the other, the throat of the reamer will have more steel to cut on the "high side" than on the "low side". Which will give the odd, crooked appearance. Production made barrels are just not made with the individual care that custom, after market barrels are.

Is there a way to "see" this inside a blank ahead of chambering? Thinking is that lapped barrels as well as button & cut rifled will all be subject to this.
If a barrel is "slugged" after chambering just ahead of the throat it probably can be detected/measured in the slug but that would be too late.
Nice to know ahead of time.

 

[Danny1788]

Is there a way to "see" this inside a blank ahead of chambering? Thinking is that lapped barrels as well as button & cut rifled will all be subject to this.
If a barrel is "slugged" after chambering just ahead of the throat it probably can be detected/measured in the slug but that would be too late.
Nice to know ahead of time.

Using a long stem DTI measuring directly on the bore will show a high land. If you use a range rod or grizzly rod you probably will never see it because you are only measuring off the ID of the bore.

 

[shortgrass]

Is there a way to "see" this inside a blank ahead of chambering? Thinking is that lapped barrels as well as button & cut rifled will all be subject to this.
If a barrel is "slugged" after chambering just ahead of the throat it probably can be detected/measured in the slug but that would be too late.
Nice to know ahead of time.

Custom made barrel blanks (made b the 'big' names) are much, much less likely to see this condition. They take care for their tooling, they have to, to maintain their reputation. I can 't see anyone who has participated in this thread measuring to 4 points ( or more!) to the right of the decimal point on the lands and grooves inside of a rifled barrel, or a slug, and being able to do it repeatably... It wouldn't take much of a difference in land height after chambering to see through a magnified bore scope image. I would expect that condition to be found in low cost after market and production made barrels.

 

[Mram10us]

Custom made barrel blanks (made b the 'big' names) are much, much less likely to see this condition. They take care for their tooling, they have to, to maintain their reputation. I can 't see anyone who has participated in this thread measuring to 4 points ( or more!) to the right of the decimal point on the lands and grooves inside of a rifled barrel, or a slug, and being able to do it repeatably... It wouldn't take much of a difference in land height after chambering to see through a magnified bore scope image. I would expect that condition to be found in low cost after market and production made barrels.

I'm curious how many Wilson, criterion, x-caliber and green mountain barrels you've measured and how they compared to the big barrels. Or where you got your evidence to back the "low cost aftermarket" comment. I've chambered a lot of wilson, but none of the other three and curious.