stagpanther
New member
I make an inert cartridge for just about every load I develop--especially for AR's. Just because a cartridge properly conforms to the case gage doesn't mean it's going to feed reliably.
ar15 loading issue
- Thread starter jproaster
- Start date
It helps to know what the gauge is designed to check ,what you are checking and why.
No offense intended,but many of the folks who dismiss a case guage don't know what they are doing with it. They mis apply the tool and then think it does not work.
I assume we are talking about what may be called a "bushing cartridge headspace gauge" I'm not directing these comments to another type guage.
What is this guage designed to do? As a bonus,it will check if cases are over trim length. So will a calipers,or a case length gauge.
I would not buy a bushing gauge to check trim length.
What I greatly value the bushing gauge for is measuring or checking the case head to shoulder datum measurement as it applies to chamber headspace.
IMO,a bushing gauge is my preferred tool for setting my sizing die to give me a repeatable head clearance.
IMO,for that purpose,it excels.
Simply using the step on the case head end,you can assure you are sizing to SAAMI spec for head clearance purposes. To be clear,I do not ask this gauge to check anything else. It does not,and cannot,check any diameters. Its not a plunk or chamber gauge. If that is your expectation,you don't understand gauging.
Thats not a problem with the gauge.
I take the use of my bushing gauge one step farther. Yes,I can simple use the step to assure my cases are within SAAMI high/Low limit.
But suppose I want .002 head clearance for my rifle.
No problem.Assuming the neck is trimmed so it does not protrude from the gauge
I can drop the case in the gauge and measure over the length of the case and gauge as an assembly. I measure from the neck end of the gauge to the case head. Assume its an unsized case and I want to shorten it .002.
I have couple of possibilities. The gauge provides me with the SAAMI hi/lo step. I can mic or caliper it. Maybe I know I want .003 over the SAAMI minimum step. Easy. Set the die so you can measure with calipers over the case assembled into the die. Its a lot like the Hornady clamp on the calipers Lock and Load setup.its just all there in the bushing.
And,like the Hornady Lock-and Load or the RCBS Precision mic,you can take a before and after comparative measurement to see how much the length changed during sizing.
If you write your numbers down,you can easily set you sizing die at .002 head clearance,or .004 or whatever you want. If you are fortunate enough that your fireformed brass is zero head clearance (and it may not be) you can simply size it so you get the desired change. Once you know that number,three years later you can repeat it with the gauge. Your gauge will be the repeatable standard.
Your calipers will do.
As a machinists,I take it to the next level. I have a comparator stand. It an 8 in square piece of very flat granite that has a 12 in tall post sticking up out of it. The post is to hold a dial indicator. I can zero the dial indicator on the high/low limit step of the gauge, Then I can drop cases in the gauge and slide the case heads under the indicator,
I just don't understand the perception that a bushing gauge is not useful.
A bushing guage physically cannot perform as a chamber plunk gauge. To measure the length,there must be clearance on the diameters.
If it can measure diameters,it cannot be free to measure length. They conflict.
If you have been trying to use your bushing gauge as a plunk chamber gauge,yes! You have been disappointed.
If I try to use a vise for a drill,I'll be diappointed. I might think my vise is useless.
Whose fault is that?
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Bonus tip!:
As I have the comparator stand and indicator
And I also have Vee-Blocks
I can stand a vee-block up on end,and put a bolt,an AR bolt,for example in the vee block with the rear,bearing face of the locking lugs resting on the upper surface of the vee block The vee block simulates the locking surfaces inside the receiver. Suppose I want to compare 4 AR bolts for headspacing purposes. Maybe I need .001 or maybe I want to match or verify another bolt. This setup can do it.I just set the indicator on the breech face.
No offense intended,but many of the folks who dismiss a case guage don't know what they are doing with it. They mis apply the tool and then think it does not work.
I assume we are talking about what may be called a "bushing cartridge headspace gauge" I'm not directing these comments to another type guage.
What is this guage designed to do? As a bonus,it will check if cases are over trim length. So will a calipers,or a case length gauge.
I would not buy a bushing gauge to check trim length.
What I greatly value the bushing gauge for is measuring or checking the case head to shoulder datum measurement as it applies to chamber headspace.
IMO,a bushing gauge is my preferred tool for setting my sizing die to give me a repeatable head clearance.
IMO,for that purpose,it excels.
Simply using the step on the case head end,you can assure you are sizing to SAAMI spec for head clearance purposes. To be clear,I do not ask this gauge to check anything else. It does not,and cannot,check any diameters. Its not a plunk or chamber gauge. If that is your expectation,you don't understand gauging.
Thats not a problem with the gauge.
I take the use of my bushing gauge one step farther. Yes,I can simple use the step to assure my cases are within SAAMI high/Low limit.
But suppose I want .002 head clearance for my rifle.
No problem.Assuming the neck is trimmed so it does not protrude from the gauge
I can drop the case in the gauge and measure over the length of the case and gauge as an assembly. I measure from the neck end of the gauge to the case head. Assume its an unsized case and I want to shorten it .002.
I have couple of possibilities. The gauge provides me with the SAAMI hi/lo step. I can mic or caliper it. Maybe I know I want .003 over the SAAMI minimum step. Easy. Set the die so you can measure with calipers over the case assembled into the die. Its a lot like the Hornady clamp on the calipers Lock and Load setup.its just all there in the bushing.
And,like the Hornady Lock-and Load or the RCBS Precision mic,you can take a before and after comparative measurement to see how much the length changed during sizing.
If you write your numbers down,you can easily set you sizing die at .002 head clearance,or .004 or whatever you want. If you are fortunate enough that your fireformed brass is zero head clearance (and it may not be) you can simply size it so you get the desired change. Once you know that number,three years later you can repeat it with the gauge. Your gauge will be the repeatable standard.
Your calipers will do.
As a machinists,I take it to the next level. I have a comparator stand. It an 8 in square piece of very flat granite that has a 12 in tall post sticking up out of it. The post is to hold a dial indicator. I can zero the dial indicator on the high/low limit step of the gauge, Then I can drop cases in the gauge and slide the case heads under the indicator,
I just don't understand the perception that a bushing gauge is not useful.
A bushing guage physically cannot perform as a chamber plunk gauge. To measure the length,there must be clearance on the diameters.
If it can measure diameters,it cannot be free to measure length. They conflict.
If you have been trying to use your bushing gauge as a plunk chamber gauge,yes! You have been disappointed.
If I try to use a vise for a drill,I'll be diappointed. I might think my vise is useless.
Whose fault is that?
----------------------------------------------------------------------------------
Bonus tip!:
As I have the comparator stand and indicator
And I also have Vee-Blocks
I can stand a vee-block up on end,and put a bolt,an AR bolt,for example in the vee block with the rear,bearing face of the locking lugs resting on the upper surface of the vee block The vee block simulates the locking surfaces inside the receiver. Suppose I want to compare 4 AR bolts for headspacing purposes. Maybe I need .001 or maybe I want to match or verify another bolt. This setup can do it.I just set the indicator on the breech face.
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Thanks all for sharing more "know how" information. I've got quite a bit to learn to be a safe reloader.
As to the trimmer, I thought I'd try a Giraud Tri trimmer. They're apparently closed til Aug 10 if I remember the company's recorded message correctly. Hope I can get one sooner than later.
John
As to the trimmer, I thought I'd try a Giraud Tri trimmer. They're apparently closed til Aug 10 if I remember the company's recorded message correctly. Hope I can get one sooner than later.
John
To be honest, I didn't realize I needed to trim. The person who helped me get started has reloaded for years and has loaded thousands of 223; he never brought it up. The fault is my own though; should've read the materials closer.
As to trimmers, I'm hoping to obtain the Giraud TriTrimmer asap.
As to trimmers, I'm hoping to obtain the Giraud TriTrimmer asap.
Oh ok , then yeah not trimming them can be the whole problem . At first I thought the way you explain the problem you just needed to turn your die down a little bit and size the case is a little more . In that same line of thinking did you full length size your cases or did you just neck size ?
hammered54
New member
Im at a loss here....when setting up a die its turned down to touch the shellholder....how will turning it down anymore push the case farther into the die?
Hammered54 said:
That is a perfectly good question . I'll answer it this way , you don't always need to follow the die manufactures instructions to the letter and often it's actually a bad idea if you want your cases to last more then 2 or 3 reloads . the reason is most commercially made chambers are not at minimum spec which adjusting your die to touch a standard shell holder will size your cases to min spec or even shorter .
Many/most bottle neck cartridges headspace off the shoulder like 308 , 223 , 300 blk . This requires you to size your case to the correct size from head to shoulder in order for it to fit in the chamber of your rifle . To little sizing and you'll have failure to feed because they don't fit in the chamber and to much sizing and you can reduce case life or even have head separation which could be catastrophic . This IMO is much more important to learn how to do correctly then COAL . COAL is simple because when you are starting a new , just use the manuals recommended COAL and you should be gtg .
However in many cases following the die manufactures directions will cause you to size your case to short from case head to datum point on the shoulder and you will reduce case life to as little as two loadings before case head separation .
These are cases only reloaded 3 times and were sized each time as Redding's instructions say to adjust your FL sizing die . ( screw down until contact with shell holder then another 1/4 turn or so )
When your case is sized much shorter then your rifle's chamber the firing pin strikes the primer and pushes the case fully forward until it stops on where it headspaces off of . In the 300 blk that would be the case shoulder stopping on the chamber shoulder . If the case is sized .008 or more shorter then the chamber when the case is pushed forward that leaves a gap of that same amount between the head of the case and bolt face .
Ok almost simultaneously the firing pin strikes the primer , case moves forward and pressure starts to build expanding the case sealing the chamber and the case actually grabs the chamber walls and is stuck in place until the pressure drops . Well what happens to that gap between the case head and bolt face because the case is stuck to the chamber walls and can't move rearward . As the pressure builds , at some point the pressure gets high enough to actually stretch the case at the web ( section of the case above the head ) and the head of the case is forced back against the bolt face . When that stretching accrues it is actually thinning the case wall at the web each time the case is fired and resized to short for the chamber . As you can see with the picture above it only took 3 sizing and firing cycles to stretch the web so thin the case failed ( NOT GOOD ) .
In a bolt gun properly sized cases can be reloaded 10 , 20 and even 40 times . In semi auto's you may not get as many as a bolt gun but if you size your cases correctly you should get 6 to 10 reloads and if you anneal maybe many more . OK so what is the "correct" size to size a case ? I don't know , I just made all that crap up , lol just kidding .
In bolt guns you want to size your cases .001 to .002 shorter from head to datum then your fire formed cases from the same rifle they will be fired in . For semi autos you want to FULL LENGTH size your case .003 to .004 shorter then your fire formed cases from same rifle .
OK so size your cases correctly , trim every time at first and use the bullet manufactures recommended COAL and you should be gtg
If you'd like we can talk press flex/deflection and how that causes cases to size longer then you think they should be .
When you put a load on a press and it's linkage it flexes and or deflects resulting in that die not touching the shell holder when you're actually sizing a case .
Example -
Here are two photos of a die set up to touch the shell holder when not sizing a case and another photo of that same die adjustment and the orientation of the die and shell holder when actually sizing a case .
No case in the die
Actually sizing a 308 case with the same die setting
Note how the gap appeared once you put a load on the press . this means even though you think you screwed the die all the way down you can actually screw it down more and the case will be sized more . that flex/ deflection is why the instructions say screw it down an extra 1/4 to 1/2 turn . A lot of guys think there die is as low as it can go but find they still have that gap when sizing a case , if you do you can screw the die down more .
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Dies don't need to touch the shellholder at the top of the ram stroke........
* If the bullet doesn't need to be crimped in with a conventional seater die.
* If the fired case shoulder wants to be set back only a thousandth or 2 with a conventional full length sizing die.
hammered54
New member
I reload for 30.06 ( for my 03) FL everytime as per instructions (rcbs dies) fits case gage perfectly I have no problems with headspacing what so ever......the question was how do you make a case shorter when the die is at the shell holder ( can't push it any farther unless you have undersize shell holder)...screwing die in more does nothing...case is as far in as its going to go.......so?
Matt.
Matt.
Metal god,
Pretty good description of the sequence of firing event. Here some icing to put on your good cake.
Bolts with inline ejectors push the loaded cartridge forward to its stop at the chamber shoulder when the bolt closes.
With other types of ejector's, the firing pin drives the case much harder usually setting the case shoulder back a thousandth or more. Easy for a 2+ ounce firing pin pushed by a 25+ pound spring force.
Primers fire a few microseconds after the cartridge is full forward hard against the chamber shoulder from firing pin impact. Takes that long for the firing pin moving near 20 fps to dent the primer at least .020 inch to fire it.
Pretty good description of the sequence of firing event. Here some icing to put on your good cake.
Bolts with inline ejectors push the loaded cartridge forward to its stop at the chamber shoulder when the bolt closes.
With other types of ejector's, the firing pin drives the case much harder usually setting the case shoulder back a thousandth or more. Easy for a 2+ ounce firing pin pushed by a 25+ pound spring force.
Primers fire a few microseconds after the cartridge is full forward hard against the chamber shoulder from firing pin impact. Takes that long for the firing pin moving near 20 fps to dent the primer at least .020 inch to fire it.
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hammered54
New member
I cam over so this is not a problem....I guess what Id like to know is how turning the die in 'any' farther will make a case shorter....when its in as far as its ever going to go... ram is at the top and no flex....( assuming your using the normal .125 shell holder )
Matt.
If you're camming over the die and shell holder are making firm contact . In that case you can not size the case any more then that . To be fare to me , I'm thinking you don't know to trim a case after sizing ?? There could be all sorts of things your buddy forgot to tell you so I started throwing things out there I believe are important to know/understand . Right about now it's pretty clear I could have done a better job getting my point across . Sorry about that , I'll try to do better next time
hammered54
New member
Im not the OP....and yes I trim after sizing....also wasnt trying to hijack this post...but when someone says to " bump the shoulder to make the case shorter" ( as in this thread)....Id like to know how thats done?
Check out post 49 in this thread.....
https://thefiringline.com/forums/showthread.php?p=6805088&highlight=post6805088
Start your own thread about this.
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For those who responded with helpful considerations...I've realized that a "start at the beginning" is in order. Got my hands on a 9th edition Abc of Reloading text and have a life-long reloader friend coming by this week. Hopefully I will get my sea legs soon.
Concerning trimming, which some of you correctly assessed was a problem,..I ordered a Giraud TriTrimmer today.
Looking forward to learning a great craft.
John
Concerning trimming, which some of you correctly assessed was a problem,..I ordered a Giraud TriTrimmer today.
Looking forward to learning a great craft.
John
Or, some might say, <ahem> addiction...
I've found that case life depends more on the relationship between chamber size and sizing die size, the amount of sizing being done, the level of loads being fired and what gun they are being fired in.
Loading for semi auto rifles involves more sizing and working of the brass than other designs need. You HAVE to size the brass small enough so the mechanism can chamber it. There is a limited amount of force and camming action available in a semi auto. A bolt action's force is you, not a spring. Makes a difference.
I've been using the same Lyman .308 Win sizer since the early 70s. Screwed down against the shellholder. I've got brass fired half a dozen times or more without failure. Fired from a bolt action. Full length resized. Not a problem.
Other side of the coin, I've got a .303british that FL sizing the brass means MAYBE 2 or 3 reloads (or less) then the brass fails. Why? Big chamber, small die. Everything is "in spec" but the spec is the case headspacing on the rim. Neck sizing that .303 and cases last4-6 firings, ..usually.
Me said:
You said:
I read that as you agree with my statement ? You point out at least 4 ways your die "may" be set up different then the "one" way most die manufacturers recommend . After readjusting my dies to size to my chamber and getting competition shell holders so I can still cam over while sizing my cases longer then they would if camming over on a standard shell holder . I now get 10+ reloadings per case . I don't know how many more I can get because I use large lots of brass ( 500 to 1000 ct lots ) so to reload only one lot of my brass 10 times gives me a minimum of 5k reloads . I have 2 1k+ lots and 5- 500ct lots of different year LC cases . I anneal at the 4 or 5 reload mark but instead of annealing right away I switch to a different lot of brass . Needless to say I've not reloaded and shot enough of my brass to have reloaded any one lot more then ten times
I have 1 lot that has 10 reloads and needs annealing , one lot that has 4 reloads and needs annealing , 1 lot on there 2nd reloading and several still on there first reloading . I suspect I will not know how many I could actually get for several years , maybe decades 
That's interesting , cus even though the cartridge headspaces off the rim the fact it has a shoulder means you can size them as if they were rimless bottle neck cases . I'd think neck only sizing would extend life considerably which I guess double is but would think 4 or 5 times that would be possible .
Is it the primer pockets that are going or case head separation ? Maybe split necks which annealing on the 3rd reload may fix ?