Shoulder bump
- Thread starter wheelgun7360
- Start date
@fguffey Are we talking semantics here? Bump shoulder back versus brass flow forward? At the end of the day, are we not achieving the same thing—a shorter case head to shoulder length?
Let’s do a little test. Take your favorite sharpie and mark a perfect line around a fired case exactly at the shoulder. Resize the case using a F/L die and tell me where the line moves? I think this will confirm that the brass flows forward, which in essenence also bumps the shoulder back relative to it’s previous length. What is the argument here? Semantics correctness?
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I think it flows forward. If you form cases from something longer, the neck really grows in length as the shoulder is moved shorter. The post number 24 also states this. Matt
So the bottom of neck just above the shoulder gets thicker or the case gets longer? Sounds like I need to spend more time with my mic.
Ben
It gets longer. That’s why we have to trim after resizing occasionally.
It always grows longer. But if the case walls of the newly formed case are thicker, the shoulder gets thicker and so does the neck. Matt
Here's a good explanation of how fired case headspace changes when full length sized as much as possible:
http://thefiringline.com/forums/attachment.php?attachmentid=85562&stc=1&d=1356646607
Do your own measurements on a fired case starting with the full length sizing die backed up one full turn (about .072" higher) from where the shellholder stops against its bottom.
Clean then measure that case's length, headspace and shoulder diameter, record their values as 'fired,' lube that case then resize it. Note the case neck is sized down back to about 1/14th inch in front of the shoulder.
Measure case length, headspace and shoulder diameter, record their values, then record them as "1st sizing."
Turn the die down 1/16th turn (about .0045"), resize again then measure that case's length, headspace and shoulder diameter, record their values as "2nd sizing."
Turn the die down another 1/16th turn, resize then measure that case's length, headspace and shoulder diameter, record their values as "3rd sizing."
Repeat this cycle over one full turn of the die. Then note how those three case dimensions change with each .0045" change in die position.
http://thefiringline.com/forums/attachment.php?attachmentid=85562&stc=1&d=1356646607
Do your own measurements on a fired case starting with the full length sizing die backed up one full turn (about .072" higher) from where the shellholder stops against its bottom.
Clean then measure that case's length, headspace and shoulder diameter, record their values as 'fired,' lube that case then resize it. Note the case neck is sized down back to about 1/14th inch in front of the shoulder.
Measure case length, headspace and shoulder diameter, record their values, then record them as "1st sizing."
Turn the die down 1/16th turn (about .0045"), resize again then measure that case's length, headspace and shoulder diameter, record their values as "2nd sizing."
Turn the die down another 1/16th turn, resize then measure that case's length, headspace and shoulder diameter, record their values as "3rd sizing."
Repeat this cycle over one full turn of the die. Then note how those three case dimensions change with each .0045" change in die position.
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Thanks Bart, this is a perfect example of a picture is worth a 1000 words.
Ben
I'm the person those remarks are referring to.
Never thought I and a friend needed to weigh our case being fired a few dozen times. We both knew anyone worthy of knowing could calculate the volume of brass turned off .010" of a 30 caliber case neck .013" thick, look up the mass per cubic unit of 70-30 cartridge brass then do some high school math to find out how much case weight was lost per case trim event.
Or use a precision lab balance to weigh either the freshly trimmed case or its mouth's shavings to subtract each time.
Does it matter the case ended up a few tenths grain less after it's fired a few dozen times and trimmed half a dozen times?
dmoran
Donovan Moran
@fguffey has been shown many times over the years, how shoulders do move and brass flows. He either abandons those threads and waits for a new thread to start, or jumps over those replies acting like they don't exist.
He literally makes 1000's of post a year on several forums all over the internet, repeating the same things over and over and over, with copy & paste being his best constituent. From which is obvious he spends little time doing anything else, other then posting his egotistical and bulling mentality on the internet daily.
He literally makes 1000's of post a year on several forums all over the internet, repeating the same things over and over and over, with copy & paste being his best constituent. From which is obvious he spends little time doing anything else, other then posting his egotistical and bulling mentality on the internet daily.
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That attachment shows what ignorant people do when they cannot understand nor comprehend reality.
Decades ago, they were often called ignoratiolinguists. Some were eleemosynarys, too.
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Dusty Stevens
Shiner
Bart- do you know who guffey is? Im still trying to find somebody that does. He gets a bat signal when somebody has a reloading problem or theres a post with the keyword “headspace” pops up. He tells tales of rescuing these ignorant reloaders, lathe under his arm solving problems only he can yet ive never heard of anybody actually getting help.
All I know about Frank Guffey is he lives in Texas and has quite different insights, compared to most others, to mechanical manipulations of rifle and ammo parts as they are made then slightly changed for any reason. For some reason, he doesn't explain his opinions' foundations to any level to support his claims. I think he is extremely unreasonable.
Years ago, I overviewed in a forum post my phone conversation with a technician at SAAMI headquarters about case headspace. He agreed it was a common industry and reloading term for bottleneck cases. It wasn't in SAAMI's glossary but was best understood for rimless bottleneck cases and their chamber headspace gauges as the same points on both were the references to measure their headspace relative to.
Frank Guffey has twisted my words from that post into a rat's nest of convoluted catrastophies matching those of his own reasoning doing his best to belittle all that good information I got from SAAMI's rep. It must be incomprehensible to Frank Guffy's wherewithal.
Some companies agreeing to SAAMI standards still claim and put in print that headspace in rimless bottleneck design is the space between breech bolt face and case head when the round fires.
SAAMI states it's the length from breech bolt face (or GO gauge head) to chamber (or GO gauge) shoulder reference diameter. That space between breech bolt face and case (or gauge) head is head clearance
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The inside of the case does not have support; that is something else a reloader can not wrap his mind around. I have said I can shorten a case from the shoulder to the case head; I also said I could not shorten a case from the shoulder to the case head by moving the shoulder back. I said I could shorten the distance from the shoulder of the case to the case head with a die that does not have case body support. That creates a big problem, I have turned cases into bellows/something that looks like an accordion when moving the shoulder back with a die that does not have case body support.
And then there are do-nuts; back to the top; that would be another 'thing' a reloader can not wrap his minds around.
It does not seem fair, when I size a case the shoulder I start with is not the same shoulder I finish with.
I know:
Not true, reloaders assume they can move the shoulder back, I can't move the shoulder back, when I form a case part of the case body becomes part of the shoulder and part of the shoulder becomes part of the neck.
F. Guffey
I suggested a reloader scribe the case, I suggested had Hatcher scribed his cases when he moved the shoulder forward on his test chambers we would not be having this conversation. reloader knew the case would not stretch .060" between the case head and case body. The problem was created when reloaders assumed the case stretched.
I said I fired 8mm57 ammo in one of my 8mm06 chambers, for those that can keep up and do not believe the firing pin drives the shoulder of the case forward to the shoulder of the chamber, that is .127" clearance.
The part that reloaders do not understand, the shoulder of my 8mm57 case did not move and the case did not stretch .127" between the case head and case body. Again, the shoulder did not move. The shoulder of the case became part of the case body and the neck almost disappeared when it became part of the shoulder.
Scribe the case: I have suggested the reloader scribe the case at the case body/shoulder juncture.
F. Guffey
And the new shoulder is not the same shoulder you started with because the old shoulder became part of the case body and the neck became part of the shoulder. The shoulder did not move back, it was not bumped back. I am not trying to run reloaders into the curb; cases do separate between the case head and case body, again I have suggested reloader scribe a line at the case body/shoulder juncture, what happens when the shoulder moves forward when the case is fired?
F. Guffey
Dusty Stevens
Shiner
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