Looking for advice on this chamber

[Hybrid284]

Hi, beginner here looking for some advice on this chamber I cut. A couple of pics from the teslong. I noticed a couple of minor scratches running length wise in the neck area, is the floating reamer holder the culprit? And i also noticed where the reamer cut the grooves in the throat area are not flat across. All of the grooves show this pattern, and my practice chambers did not. Also a shout out to the experts on this forum, your comments are appreciated and have been a big help. Thankyou, cheers Jake.

 

[Walt Krafft]

A little polish with some Scotch Brite should get rid of the scratches. The pattern in the throat is normal. Some look a lot worst depending on the type of rifling. As long as they are the same all the way around you are good.

 

[tobnpr]

All of the grooves show this pattern, and my practice chambers did not.

I don't think I'd eff with the scratches in the neck, JMO
Since you say the start of the leade has always been perfectly "clean" across the bottom edge until now, I suspect the reamer may be getting dull there. Remember, that's the most delicate part of the reamer that needs to be razor sharp to give that clean edge- and it's also the part that gets the most use/wear as it cuts from beginning to end, drill/pre-bore will reduce that wear and extend reamer life.

Just my $.02..

 

[Hybrid284]

I don't think I'd eff with the scratches in the neck, JMO
Since you say the start of the leade has always been perfectly "clean" across the bottom edge until now, I suspect the reamer may be getting dull there. Remember, that's the most delicate part of the reamer that needs to be razor sharp to give that clean edge- and it's also the part that gets the most use/wear as it cuts from beginning to end, drill/pre-bore will reduce that wear and extend reamer life.

Just my $.02..

This chamber was with a new reamer, the first cut with it. And it was with a pre bore. Thanks for the advice.

 

[DShortt]

It appears to me that the scratches were probably in the barrel beforehand. And they are insignificant. I'd not worry about them.
As for the throat not being completely flat across the grooves, that's the profile of the bore. Again, pretty insignificant. Providing this is consistent all the way around, I'd not worry about that, either.
Shoot it.
You're going to be forcing a copper jacketed piece of lead down that bore driven by several 10's of thousands of pounds of pressure. And after the first shot, it'll have fouling that the bullet is being driven over in the bore.
It won't ever look this good again.

 

[Tommie]

It appears to me that the scratches were probably in the barrel beforehand. And they are insignificant. I'd not worry about them.
As for the throat not being completely flat across the grooves, that's the profile of the bore. Again, pretty insignificant. Providing this is consistent all the way around, I'd not worry about that, either.
Shoot it.
You're going to be forcing a copper jacketed piece of lead down that bore driven by several 10's of thousands of pounds of pressure. And after the first shot, it'll have fouling that the bullet is being driven over in the bore.
It won't ever look this good again.

Agreed. Mostly what I’m seeing looks like button chatter from the barrel manufacturer. Seems that bore scopes have shattered our fantasies of perfect bores and chambers. Either way, it’s time to shoot.

 

[Judd]

Just wait until you get one of those buttoned barrels where the center isn’t as tall as the edges…I had no idea how I had screwed that up They look like a U. What you’re looking for is that they all look identical. By and large, the rest…we don’t control.

 

[BuffaloBill]

I’m far from an expert having only chambered 7 myself. But the satisfaction that came from that first one shooting tiny groups was huge. I bet your’s will too. This is a highly addictive and rewarding hobby!

 

[tobnpr]

Just wait until you get one of those buttoned barrels where the center isn’t as tall as the edges…I had no idea how I had screwed that up They look like a U. What you’re looking for is that they all look identical. By and large, the rest…we don’t control.

Like this?




Groove radius is larger than nominal, this is what causes the "half moon". Perfectly cut/concentric chamber, it's not a defect from the process.

 

[Judd]

Exactly like your drawing @tobnpr, it was so weird I took that one to my mentor and was like WTH did I do wrong here. He started laughing and said “you haven’t done enough button barrels yet, kid”

Funny, it’s a Benchmark 6.5 that is a saum and it hammers, especially for a 16” hunting rifle.

I’ve had one exactly like your picture too…that’s where the center is higher. It shot too.

 

[X Count]

If I get a chance I'll post some photos of a cracker button barrel.

 

[boltfluter]

Hi, beginner here looking for some advice on this chamber I cut. A couple of pics from the teslong. I noticed a couple of minor scratches running length wise in the neck area, is the floating reamer holder the culprit? And i also noticed where the reamer cut the grooves in the throat area are not flat across. All of the grooves show this pattern, and my practice chambers did not. Also a shout out to the experts on this forum, your comments are appreciated and have been a big help. Thankyou, cheers Jake.View attachment 1701966View attachment 1701967

Looks like you cut a great chamber to me! Well done, now let's see some groups.
Paul

 

[Will Henry]

The U shaped lands seem to be a fairly recent thing in buttoned barrels. Old Hart, Douglas, and Shilen barrels don't seem to exhibit this but newer barrels often do. Now, it's important that I mention, I have made exactly zero barrels and have also made none of the tooling required. Still, I do see flaws present in some recent barrels which I didn't see before. One barrel I looked at had one U-shaped land, while the others were normal. Another had one land which was measurably low. In both cases, the flaw was evident only at the breech and had resolved itself in about six inches. My feeling is that it is the result of the bore diameter of the button being a bit smaller than the reamed barrel. I suspect, in order to produce a perfect buttoned barrel, the diameter of the reamed bore is more critical.
I started shooting BR when buttoned barrels ruled, with Hart and Shilen filling most of the top spots. Cut barrels from Atkinson and Sherer were less common and considered to be less consistent from barrel to barrel, though some individual barrels were superb.
The radius in the grooves is produced by the profile of the button or the cutter and may not be the same as the radius of the groove diameter. Since the reamer will cut a round surface (unless you mess it up) you will see the difference reflected in the cut. WH

 

[X Count]

Here you go! This is button barrel that had done 100 rounds or so and I cut the chamber off and re chambered. The small amount of carbon gives a really good contrast.

Was scratching my head dialling it in. Very very uniform but odd profile.