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Ringed Chamber? (Read 1209 times)

chipmaker Senior Forum Member Offline Posts: 352 Location: san diego Joined: Sep 24^th, 2007	Ringed Chamber? Aug 26^th, 2022 at 7:05pm	Print Post
	I had hopes that a recently purchased German hunting rifle would require little work before a trip to the range. Repair of a forend crack and damage to the breech end of the forend went well but a chamber cast had some surface defects that led to a closer examination of the chamber. Attached is a photo of the chamber cast alongside a 8.15X46R cartridge, with a stop ring bullet inserted. Measurements of the chamber cast show that the case is one of the many versions of the 8.15X46R. The main differences are the slightly longer case length at 1.882" (1.831") and a larger rim diameter .500" (.486"). I originally thought that the chamber rings may have been caused if the rim recess was enlarged, until I stumbled onto the brother of my rifle. My rifle was proofed in 1922, while its brother underwent proof in 1911. Both have rim diameters of .500". There is no history on my rifle but it's brother spent its life in a closet, until 2020, after coming to our shores after WW-2. I now think that the larger rim diameter is original to both rifles. To be continued


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chipmaker Senior Forum Member Offline Posts: 352 Location: san diego Joined: Sep 24^th, 2007	Re: Ringed Chamber? Reply #1 - Aug 26^th, 2022 at 7:21pm	Print Post
	I examined the chamber with a Hawkeye borescope and took the attached photos with one of the tiny flexible endoscopes. The first photo shows the chamber before cleaning. The barrel cleaning process went as follows: I remover the barrel to facilitate cleaning the chamber. 1. Bronze brush pushed and then turned (slow and fast) in a drill —— Little if any change 2. Heated the chamber area to the cerosafe melting point and then used the bronze brush. —— debris not Cerosafe 3. Scrubbed chamber area with the bronze brush wrapped with 0000 steel wool —— Debris gone but rings still present 4. Polished chamber with 220 gr cloth paper —— Rings better but still visible The second picture shows the chamber area, after the cleaning. The mass in the center is a white cleaning patch to improve lighting. The rifling looks good but I’m not sure how to interpret the rings. I've never seen a chamber ring. The proximal ring is at about 1.6" from the barrel breech end. My Questions 1. Does this look like a "ringed chamber"? 2. If the rings don't affect accuracy or extraction, is it generally safe to shoot? 3. Is there some test of barrel integrity for barrels with ringed chambers? Thanks for your help, Otto


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John Taylor Frequent Elocutionist Offline Posts: 1774 Location: Lewiston, ID Joined: Oct 23^rd, 2006	Re: Ringed Chamber? Reply #2 - Aug 26^th, 2022 at 7:54pm	Print Post
	It does not look like a ringed chamber. Groves possibly caused by removing a separated case. If there is a problem with extraction the chamber could be lined but I doubt that it would end up with the same chamber.

	John Taylor Machinist/gunsmith
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texasmac Frequent Elocutionist Offline Posts: 2006 Location: Central Texas Joined: Aug 16^th, 2004	Re: Ringed Chamber? Reply #3 - Aug 26^th, 2022 at 10:29pm	Print Post
	Here's my thoughts. As noted in the following photo the well defined ring looks like a chamber ring & is where I'd expect to find one at the base of the bullet. The others I noted as possible wrinkles may also be chamber rings caused from longer or deeper seated bullets. But they also may just be wrinkles in the cast. I would make another cast to see if the same things shows up. Or fire a fully loaded cartridge & see if any of the possible rings transfer to the case. Wayne


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chipmaker Senior Forum Member Offline Posts: 352 Location: san diego Joined: Sep 24^th, 2007	Re: Ringed Chamber? Reply #4 - Aug 27^th, 2022 at 11:06am	Print Post
	JT & TM Thanks for your responses. I'll do another chamber cast to check for wrinkle artifacts. I'll also load some cartridges for firing and a extended length cartridge for fire forming. Otto


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Cbashooter Frequent Elocutionist Offline Posts: 1600 Location: Eastern Wa. Joined: Mar 31^st, 2018	Re: Ringed Chamber? Reply #5 - Aug 27^th, 2022 at 12:24pm	Print Post
	I had an 8.15x46 Mauser thst the chamber cast looked similar. The end of the chamber looked like a drill with chips spun there a few times.my guess was a case neck broke off and it was damage from the attempt to remove it.the rifle still shot very well.
	« Last Edit: Aug 27^th, 2022 at 12:51pm by Cbashooter »

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chipmaker Senior Forum Member Offline Posts: 352 Location: san diego Joined: Sep 24^th, 2007	Re: Ringed Chamber? Reply #6 - Aug 27^th, 2022 at 1:40pm	Print Post
	The chamber cast after the cleaning and polishing described above is shown below. The wrinkles are gone as is half of the proximal ring. The chamber transition step is unchanged. I suspect that the preceding suggests that the rings were burrs as opposed to concave rings. Does this seem correct or are there alternate explanations? Otto


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Cbashooter Frequent Elocutionist Offline Posts: 1600 Location: Eastern Wa. Joined: Mar 31^st, 2018	Re: Ringed Chamber? Reply #7 - Aug 27^th, 2022 at 2:01pm	Print Post
	See my comment above it looks exactly like the chamber cast of mine. That's my best guess anyway.


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Jeff_Schultz ASSRA Board Member Online Posts: 1631 Location: Ransomville, NY Joined: Apr 25^th, 2004	Re: Ringed Chamber? Reply #8 - Aug 27^th, 2022 at 7:24pm	Print Post
	Myself, I'd be more concerned with what it shoots like, than what it looks like.

	"We have met the enemy and he is us." Pogo “There is no situation so bad that it cannot be made worse." Confidence- The feeling you get before you fully understand the situation.
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chipmaker Senior Forum Member Offline Posts: 352 Location: san diego Joined: Sep 24^th, 2007	Re: Ringed Chamber? Reply #9 - Aug 27^th, 2022 at 8:15pm	Print Post
	It seems as if the consensus is that the chamber was damaged most probably in extracting a separated case. Nearly all of the proximal ring polished out, so its ready for reassembly and test firing. Thanks to all who responded. Otto


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bnice Frequent Elocutionist Offline Posts: 1900 Location: Iowa Joined: Nov 30^th, 2006	Re: Ringed Chamber? Reply #10 - Aug 28^th, 2022 at 4:23am	Print Post
	This would be a good justification to do a chamber picture when new. Would guess as one mentioned machining marks from buds could look similar.


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