Easier said than done, I always end up with a few odd balls, hence my original question.
Max head space?
- Thread starter 500Stroker
- Start date
My favorite cases are cases that will not chamber because the length of the case is too long from the shoulder to the head of the case and or the case body is too large in diameter. No one ever ask; "WHY?", Manufacturers of cases do not make cases for reloaders that know what they are doing. If the manufacturer made cases that would not chamber I could use the cases to off set the length of the chamber, it is not possible to off set the length of the chamber with a case that starts out being too short from the shoulder to the case head.
Next comes forming dies; I have used 280 Remington cases for long 30/06 chambers. I have used 30/06 cases for 8mm57 cases etc..
Next best source of long cases; the firing range, I have gone to firing ranges with case length measuring tools when selecting cases that have been fired in trashy old chambers. Cases that have been fired in trashy old chambers will not allow the bolt to close unless they are sized. There is a belief a case that has been fired in a trashy old chamber is suspect.
F. Guffey
Brians356
Silver $$ Contributor
A little late to this party ("Party on, Garth!") but to the OP:
Suppose, for illustrative purposes, that your original question, taken at face value, concerned safety alone. From my own observation factory ammo in a typical factory chamber can sometimes have as much as .010" of headspace, but commonly .007" - .008".
Seems like a lot. But consider SAAMI specs for, say, 223 Remington:
Cartridge Max datum length is "1.4666 - .0070" meaning the calculated Min datum = 1.4596.
Chamber datum Min = 1.4636 and Max = 1.4736 (these are explicit.)
Chamber Max datum minus Cartridge Min datum = 1.4736 - 1.4596 = .014. So, in theory, a SAAMI-compliant cartridge in a SAAMI-compliant chamber could have .014" of instantiated headspace in this example. Most cartridge's headspace calculations will be very similar.
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Suppose, for illustrative purposes, that your original question, taken at face value, concerned safety alone. From my own observation factory ammo in a typical factory chamber can sometimes have as much as .010" of headspace, but commonly .007" - .008".
Seems like a lot. But consider SAAMI specs for, say, 223 Remington:
Cartridge Max datum length is "1.4666 - .0070" meaning the calculated Min datum = 1.4596.
Chamber datum Min = 1.4636 and Max = 1.4736 (these are explicit.)
Chamber Max datum minus Cartridge Min datum = 1.4736 - 1.4596 = .014. So, in theory, a SAAMI-compliant cartridge in a SAAMI-compliant chamber could have .014" of instantiated headspace in this example. Most cartridge's headspace calculations will be very similar.
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Way i see it for a reloader saami spec means little. After fireforming as long as you are just (bumping) the shoulder back 1 or 2 thousandths you should be good to go.
Certainly don't want to resize back to sammi minimum or the factory length.
It sounds like you are including cases that have been stretched by firing in over length chambers.
I do not care to used stretched cases for reasons that must not be obvious to you.
It is not a belief that cases fired in a trashy old chamber are suspect. It is fact until proven otherwise.
I cannot believe that you advocate the use of cases that may be damaged by firing in over length chambers.
I do not care to used stretched cases for reasons that must not be obvious to you.
It is not a belief that cases fired in a trashy old chamber are suspect. It is fact until proven otherwise.
I cannot believe that you advocate the use of cases that may be damaged by firing in over length chambers.
jepp2
Gold $$ Contributor
I am interpreting your comment of "creating problems" to be a case life question, not an accuracy question.
I don't disagree with keeping brass for a specific rifle, but for my AR's, I want the flexibility to use my fired cases in any of them. So I size so the cases will work in any of them. But normally I am still within the 0.003" shoulder setback on sizing anyway.
Getting to the point. I recently completed a case life test. I wanted to see how long brass fired in an AR would last. And I wanted to see how it would fail. So I picked up 20 LC cases at the range that I knew were once fired. And each time I sized the cases, I set the shoulder back 3-4 thousandths. I did the paperclip test each firing (although I can identify incipient case head separation by the visible ring as soon as I can with the paperclip test). I annealed every 5'th firing. My cases lasted at least 35 firings with no sign of excessive case stretching. All of my case failures were due to "gouges" created by the barrel extension lugs (I had just re-barreled this AR). The sharp edges on the new barrel extension was tough on the case necks.
Brians356
Silver $$ Contributor
SAAMI specs mean a lot if the question was "Is it unsafe to fire a cartridge with X thousandths excess headspace?", e.g. one sized for a different rifle. Or if it was "What is the maximum headspace that is allowed?" Or "Can I safely shot [sic] the shorter brass in the longer chambered rifle without creating problems?"
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I was taught, among other things, that as a machinist you hit the target dimension. Specifically in regards to the chambering of a barrel I was taught that the empty bolt should just close snug on the SAAMI go gauge, which is minimum chamber length. I was always taught that since chamber length cannot do anything but increase as the rifle is fired and the action wears, etc. it is best to set it at SAAMI minimum {just close on a go-gauge}.
This is not a hard or difficult thing to do, so I have to ask....is there some reason I don't know about that all these "gunsmiths" are cutting chambers deeper than SAAMI minimum????? I mean, I am old school, but I am having a hard time wrapping my head around a "gunsmith" that after charging for his "service" misses minimum chamber length by several thousandths and simply says, "here you go Mr. customer, all done" and then the owner gets home measures things {that is if he measures anything at all!!!} finds it to be longer than ideal and in some cases I read on here out of spec and simply accepts this and sizes his cases accordingly. What about the guys that shoot factory ammo???? In a chamber that is already on the no-go spec???? I get that many guys are sizing to the chamber...but you first have to somehow get the brass way over length....then, what do you say to a potential buyer if you ever decide to sell this thing??? "yeah, the chamber easily closes on a no-go gauge, but don't worry about it!!" I must be missing something here.
This is not a hard or difficult thing to do, so I have to ask....is there some reason I don't know about that all these "gunsmiths" are cutting chambers deeper than SAAMI minimum????? I mean, I am old school, but I am having a hard time wrapping my head around a "gunsmith" that after charging for his "service" misses minimum chamber length by several thousandths and simply says, "here you go Mr. customer, all done" and then the owner gets home measures things {that is if he measures anything at all!!!} finds it to be longer than ideal and in some cases I read on here out of spec and simply accepts this and sizes his cases accordingly. What about the guys that shoot factory ammo???? In a chamber that is already on the no-go spec???? I get that many guys are sizing to the chamber...but you first have to somehow get the brass way over length....then, what do you say to a potential buyer if you ever decide to sell this thing??? "yeah, the chamber easily closes on a no-go gauge, but don't worry about it!!" I must be missing something here.
I certainly don't recommend shooting a rifle when the bolt will close on the field gauge. I have a couple of savage switchbarrels and i always set.them up snug on the go and not close on the no go.
As we know go is.saami minimum and no go is saami max and the.field gauge is.the.red flag. I think every shooter should own the go/no go gauge set or.at.the very least have someone verify their chamber on a new rifle. Humans do make mistakes.
We are in total agreement sir. Especially the part about being able to verify their chamber dimensions....but, way too many reloaders and most shooters don't even understand the term headspace. Some even believe it has to do with bullet seating depth.
Richard, I have fired ammo in one of my rifles that had .127" clearance between the shoulder of the case and shoulder of the chamber. The shoulder of the case never made it to the shoulder of the chamber and the case did not stretch between the case head and case body. Hatcher chambered a rifle with .080" difference between 30/06 ammo and his modified chamber, he did not experience case head separation; I had a friend that built 5 magnificent rifles using 03 and 03A3 receivers, he had 5 case head separations out of the first 10 cases he fired.
Again, I have a M1917 Eddystone with a chamber that is .002" longer than a field reject length gage, that means when I fire a minimum length/full length sized/factory round in that rifle I have .016" clearance between the shoulder of the case and shoulder of the chamber. When I fire a case in that rifle the shoulder on my case does not move when the firing pin strikes the primer even though I have killer firings pins in all of those rifles.
To make like simpler for me I for 280 Remington cases to 30/06 cases by adjusting the die off the shell holder .014", Adding .014" to the length of the case from the datum/shoulder to the case head give me the magic .002" clearance. Not understood by most but backing the die off .014" makes it easier to size the case.
F. Guffey
Well? We (all) are not it total agreement. I know, agreeing is like mowing the lawn, around here it is immediate neighbor hood acceptance. I afford myself the luxury of disagreeing. I do agree with verifying; I have said I am the fan of verifying, I am the fan of standards and I am the fan of transfers.
F. Guffey
One of the things i love about America. You are free to.make.your.own decisions. I would expect no disasterous results if an informed.shooter intentionally shoots a long chamber. Just make sure you are monitoring.the condition of your brass. It is that unaware shooter that gets in trouble.
There are many of.those unaware shooters out there that believe.if they jam a bullet in the lands then terrible things will happen.
I would think it would be safe to shoot if it's shorter. Measure a factory loaded round. I'll bet it's a lot more than 0.004' shorter.
Richard, true, I am the fan of 'the running start', I want my bullets to have that jump. If I have a rifle that is not accurate with a running start it does not get shot. I insist on knowing the length of the chamber from the rifling to the bolt face, I have checked rifles for length in doing so I have found chambers that were so long the bullet came out of the case before the bullet contacted the rifling.
F. Guffey
In terms of shooting, safety and accuracy, which would you guys prefer to shoot...ammo that is matched to the size of your chamber {zero headspace} or ammo that is short by .004" or greater???? If you are buying a rifle to shoot as accurate as it can would you rather have one that is done with a minimum chamber length or one that is closing on a no-go gauge????? Gunsmith shows you two rifles that appear identical and they are exactly what you are looking for, then he tells you one is dead zero minimum chamber, the other is somewhere between no-go and field...same price, which one are you taking home????
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As long as you realize that you will need custom dies to match the chamber either one can be accurate. I would prefer a minimum chamber, personally, but I don't shoot at long ranges and velocity is a distant second to accuracy. I kill things with my guns as well as punch holes in targets.
Isn't the case matched to your chamber after the first shot???
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