What would cause this circle on the case body 300 WM

[DIBBS]

While inspecting and sizing 2x fired Black Hills Match 300 WM Brass tonight, I discovered one case in the lot of brass to be sized, that had what appears to be a perfect circle just below the shoulder.

It was shot in a Bighorn SR3, unknown weather conditions since I didn't see it till now. Would a speck of water cause this, or is it more likely a manufacturing defect that wasn't discovered till now. You can feel it with your fingernail. Thanks.

 

[46and2]

I've seen this before. If it's one piece of brass with this defect it's not your chamber. I believe it is a defect or mis step in the manufacturing process while the brass was still in sheet form.
Toss it.

 

[Mark Buettgen]

From the Port in Pressure Test barrel.
Later,

 

[DaveTooley]

From the Port in Pressure Test barrel.
Later,

^^^^^^^^^^^^^^^

 

[over_thetop]

Never saw any commercial brass with test impressions. Something just BH does ?

 

[DaveTooley]

Never saw any commercial brass with test impressions. Something just BH does ?

Every ammo manufacture uses the same process for measuring pressure. You just don't see the brass in circulation.

 

[DaveTooley]

I just glanced at this but if you like to read more about it take a look.

Ways to Measure Pressure | The Ballistic Assistant

www.theballisticassistant.com

 

[DaveTooley]

It's all laid out in the SAAMI specs. Here's the 300WM drawing about the location of the port.

 

[Bill K]

Somehow it got into the brass barrel for reloading commercial instead of sidelined for pressure testing brass.
Either use it, or put up on shelf for display.

 

[Kracken McGraw]

I learn something new everyday.

 

[Alexander-M]

^^^^^^^^^^^^^^^^^^^^^
So do I, as I state on my posts!
Alex

 

[Webster]

While inspecting and sizing 2x fired Black Hills Match 300 WM Brass tonight, I discovered one case in the lot of brass to be sized, that had what appears to be a perfect circle just below the shoulder.

It was shot in a Bighorn SR3, unknown weather conditions since I didn't see it till now. Would a speck of water cause this, or is it more likely a manufacturing defect that wasn't discovered till now. You can feel it with your fingernail. Thanks.

View attachment 1597357


View attachment 1597358

The brass also has what looks like a grove where the neck joins the shoulder. I would inspect all my brass and toss any that look like they have defects.

 

[GotRDid]

I was under the impression that most mfg use the strain gages for pressure testing.
I have only seen one casing similar to this in my 50+ years of Handloading, and that was early on.

 

[Walt Krafft]

That is a strain gage pressure transducer. The transducer goes in a hole in the chamber and has to be flush with the same profile as the chamber. They can be touchy to get right.

 

[DaveTooley]

I was under the impression that most mfg use the strain gages for pressure testing.
I have only seen one casing similar to this in my 50+ years of Handloading, and that was early on.

Nope all use Transducers. Strain gages that you're thinking of aren't accurate enough. In the old days they used a copper crusher system.

 

[over_thetop]

Every ammo manufacture uses the same process for measuring pressure. You just don't see the brass in circulation.

copper crusher/Piezoelectric testing uses a transducer. Been awhile.

 

[DaveTooley]

BTW Bartlein makes the majority of pressure barrels used in the industry these days.

 

[markm87]

It's all laid out in the SAAMI specs. Here's the 300WM drawing about the location of the port.

What's in the Schwab account?

 

[Tedk]

As Bill K said, hold on to that. I'd send Black Hills a pic or two to see what they say. Don't send it anywhere.

 

[jwv2001]

Who was responsible for the 1st & 2nd firing? At any rate, I would send a pic to the manufacturer for an explanation.