After a while, it stops being funny.Yes, but you missed the entertainment.
Rick
Erosion from blowback on necks
- Thread starter Pigdog
- Start date
My take on the OP’s question is that the soot seen on necks is there from the very first bit of combustion products escaping upon ignition, maybe just as the bullet’s leaving the case. Pressures & temps aren’t nearly as high as a few microseconds later when the neck’s expanded enough to seal the back end.
As others suggest it’s throats that suffer, not chamber necks....
As others suggest it’s throats that suffer, not chamber necks....
I took this picture on a scanning electron microscope about 10 years ago. I was looking at bore erosion so I don't have a good pix of the neck area. 25X mag about 7000 shoots in a Douglas SS 6mm Rem barrel. There is only about a 1/4" on the left of the pix showing where the neck o.d. contacts the chamber. I don't see any obvious damage. Tony Boyers book briefly mentions the soot pattern being somewhat related to neck thickness. Sounds like soot is normal. I have had soot on the necks of about 20,000 cases.
A cross sectioned .222 chamber with a gazillion rounds down the barrel. Normal cleaning and nothing more. Bushing die..You can clearly see where the neck bushing stopped sizing the neck of the brass.The photo exaggerates it. There are no sharp edges in the chamber but it's very clear where the bushing stops. At the neck/shoulder junction is a glare. It's shiny but smooth with no burrs or sharp edges. About 1/16" from there is where I'm referring to.
I suspect the next ring up is the approximate area of the pressure ring of the bullet the owner shot mostly.
I see no parallel flame cutting or anything of the such...and never have, in several of these chamber disections that I've done over the years. I think the whole notion more unbased conjecture.
Clearly, this stub has served more than one purpose in its life. No idea what I threaded both ends for but likely setting up a cutter or testing for a thread fit..etc. It was scrap whenever I did that and it's come in handy a few times, to show customers since.
I suspect the next ring up is the approximate area of the pressure ring of the bullet the owner shot mostly.
I see no parallel flame cutting or anything of the such...and never have, in several of these chamber disections that I've done over the years. I think the whole notion more unbased conjecture.
Clearly, this stub has served more than one purpose in its life. No idea what I threaded both ends for but likely setting up a cutter or testing for a thread fit..etc. It was scrap whenever I did that and it's come in handy a few times, to show customers since.
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What Greyfox said!
Oh, but how about that abrasive powder and it's convergence point with long necks and steep shoulders. More conjecture. I'm the one mentioning the brass in this context but many are claiming it is a serious factor to barrel life. Again, IMHO...conjecture.
A local reloader gave me 80 7mm Remington Mag cases. The carbon around the neck was packed so tight it had to be scraped off. I called him to warn him, I thought the cases were his. He said he got the cases from a neighbor that died. My concern then was focused on the rifle, if the carbon was packed on the necks the chamber neck had to be so tight the case neck could not release the bullet etc. etc.. He contacted the family, no one knew what happened to the rifle.
He reminded me the man that died was the one that had close to 200.000 pounds of machine shop equipment for sale. He was a writer for machine shop magazines and designed reloading equipment. I want my necks to expand and seal the chamber, that makes me the only reloader that understands 'time' is a factor.
F. Guffey
Not conjecture, just something I did not know. I am glad you could straighten it out so convincingly. Nice visual aid too!
My post wasn't directly to you, since I didn't see anywhere you making suppositions about chamber erosion. But, a picture is often worth 1000 words. What doesNot conjecture, just something I did not know. I am glad you could straighten it out so convincingly. Nice visual aid too!
mean?I think Pigdog started this thread based on something I said in another thread. The faces are just that most people will give a long winded explaination that may be hard to follow, whereas you had just the right item to definitively show the answer to his exact question.My post wasn't directly to you, since I didn't see anywhere you making suppositions about chamber erosion. But, a picture is often worth 1000 words. What does
+1 on number 3 here.. You may just need to clean it really well or step up the charge a little bit... I get some soot on necks even when useing factory ammo or reloads in every rifle I shoot.. seems pretty normal on the necks , not so much all the way back to the shoulders... Are you just shooting underpowered reloads..???
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I think soot on the necks is normal. There may be a few things that determine how much soot you see. Quit worrying about it. Doesn't make sense to adjust neck thickness, neck tension and powder charge bases on soot and ignore the target. No-one ever thru a barrel away because they thought there was erosion next to the neck in the chamber. Make your adjustments based on target results forget about soot. My photo and gunsandgunsmithing photo show no damage. gunsandgunsmithing photo clearly shows the neck area of the chamber is bright, shiny, smooth and free of damage.
dogdude
Egan O'Brien
I shot some virgin Palma brass(sp) with a light load, -1.5 grns...soot to the shoulder and below, added 1.5 grns..all most no soot.
Why are you obsessed with soot on the case neck? You adjust your loads for accuracy not to remove soot. 63 PSI is way excessive for a factory action and pushing the limits on a custom action. Don't assume Quick Load is giving you accurate PSI for your loads. My Berger manual gives a max load of 38.3 grains of 4350 with a 140 gr bullet. A standard bronze brush and patches are oversize enough to clean the neck area of the chamber. Why would increasing neck tension reduce soot? You adjust tension to improve accuracy not to remove soot. Sounds like your doing everything backwards.
More neck tension would help.
Size only 1/2 of the neck. The unsized part of the neck will expand to the chamber after a few firings. It will no longer spring back.
Like my 243 win brass.
http://www.saami.org/specifications_and_information/index.cfm
The 6.5x47L 63,090 psi http://www.accurateshooter.com/featured/65x47/
The OP's loading would seem to be at maximum.
The 6.5x47L 63,090 psi http://www.accurateshooter.com/featured/65x47/
I think this is wrong. SAAMI lists many factory cartridges running at high 65,000 PSI pressures, in factory actions.
The OP's loading would seem to be at maximum.
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