case gauges

[Brian Pfleuger]

I believe the world is going to shift also, and start calling that dimension "Case Headspace" or "Cartridge Headspace".

The world has already shifted to that point, quite some decades ago, actually.

I actually called SAAMI about it, back in August of 2014. (This terminology has been Mr Guffey's major malfunction for some years now).

He (the SAAMI guy) said specifically that they do not use/approve the term because some cartridge (7mm Rem Mag and .357sig as examples) have shoulder datum line and do not headspace on the shoulder. In other words, they don't like exceptions to their terms, I guess.

He also said that the dimension commonly called "case headspace" does have a "name" of sorts but it's really a symbol with no word to describe it. Sort of like the "Artist Formerly Known As Prince".

Further, he said that they (SAAMI) are well aware that major manufacturers, such as Hornady with their "headspace gauges", use the term as it is now commonly understood (by most everyone except Mr Guffey) and they have no issues with it.

 

[Slamfire]

in the beginning I said I make datums, I collect datums and on occasion I purchase datums.

In the beginning Guffey created the heavens and the earth. The earth was dimensionless and void, and darkness was over the surface of the deep, and the Spirit of Guffey moved over the surface of the earth creating datums which could be collected and sold.

In a fantasy universe, I don't see any reason why theoretical datum's can't be physically made, collected, or sold.

http://blog.3dcs.com/Blog/bid/73215/Dimensional-Engineering-Datums-are-Important

In a dimensional engineering procedure datum design is the second critical task, right behind objective specification. Datum Design is integral to Assembly Strategies, GD&T (Geometrical Dimensioning and Tolerancing), and Measurement and Inspection Plans.

The definition of a Datum from the Dimensioning and Tolerancing Standard ASME Y14.5-2009 is:

A theoretically exact point, axis, line, plane, or combination thereof derived from the theoretical datum feature simulator.

In other words, Datums have the following characteristics.

(1) Datums are the origins from which the GD&T and Measurements are established.
(2) Datums are derived from actual datum features, not reference points, lines, or planes.
(3) Datums are theoretically exact.


https://thefiringline.com/forums/showthread.php?t=551274&page=2

Originally Posted by F. Guffey

I make datums, I collect datums and on occasions I purchase datums.

I agree with Brian Pfleuger on his statement:

You also fixate on esoteric minutia and babble without a purpose beyond what I can only assume is your intent to confuse and your own perception that it makes you sound more knowledgeable

.

 

[Slamfire]

He (the SAAMI guy) said specifically that they do not use/approve the term because some cartridge (7mm Rem Mag and .357sig as examples) have shoulder datum line and do not headspace on the shoulder. In other words, they don't like exceptions to their terms, I guess.

SAMMI is not the only one trying to turn the clock back to 700 AD or earlier. The Académie française periodically publishes an updated Dictionnaire as the official dictionary of the French language. They are trying to protect the purity of the French language by banning new word additions, particularly words that came from the dreaded English language. France has launched a new drive to stop a glut of English words from invading the native tongue. Words to be banned included "email", "blog", "fast-food" , "supermodel", "take-away" food, "low-cost", "shadow-boxing" , "detachable motor caravan" and "hashtag".

The failure for all Lexicon Ayatolla's is that trying to describe today's world, with its new and changing technology, gets to be very difficult using only 7th century words and concepts. Just how would have 7th century goat herders concisely described a Xerox Copier or Xerox copies, when even fifty years ago, these did not exist. What did the Lexicon Ayatolla's call blueprints I wonder? The wonderful thing for them, technology has made carbon copies obsolete so they don't have to fret over those words anymore.

So, according to the SAAMI Ayatolla's the only official "name" for the measurement is an "alpha-numeric character". . Since Guffey is so stead fast in standards, it is only proper that he should be using "alpha-numeric character" instead of telling us that "cartridges don't have headspace". The proper correction would be, "cartridges don't have headspace, they have alpha-numeric character". Now that is something we can all unify behind.

Ha, ha, ha, ha, ha, ha, ha, ha, ha, ha, ha, ha, ha, ha, ha, ha.

 

[308Loader]

WOW

 

[Beargrass]

case guages

Hey, Nitescout, I was not thinking of you. Yep all of us that work on rifles and build custom guns use headspace guages. I need to slow down and read more carefully. Have a happy and prosperous new year!

 

[Nitescout]

beargrass,

Thanks! This has really turned into something of a mess...I hope we can all agree to disagree, and keep on reloading and shooting!

 

[308Loader]

This post digressed into some thing way more than the OP might be able to comprehend fully in this stage of his reloading. I have read it now 3 times and learned a few little things. I am still new to all of this and have misused the term "head space" when talking about cartage dimensions. I also can see why this topic is confusing to a new loader. A chamber is cut and a bolt face closes on it, the distance from bolt face to supporting element in the chamber (mouth of a straight wall case, or datum on shoulder in bottleneck case, or belt of magnum) would be the head space of that chamber right?. It then would make sense that the brass cartage must fill this void to be properly sized for this chamber. I know it is a bit more complicated than that but back to case gages.

Uses for case gage:
1. Check circumference of cartage at its base and mouth.

2. Quick measure of trim length of rifle cartage. If it is longer than trim length it will stick out the bottom provided the above (1) is correct.

3. Quick measure of trim length of pistol cartage. If it is longer than max it will stick out the top provided the above (1) is correct.

4. Quick Go - No Go. Will the remanufactured round chamber in most any gun designed for that chamber.



Is a case gage a good tool for setting up your equipment? I think so.

 

[cw308]

I think all TonyZ wanted to know if a loaded round could go into a case gage, yes it tells you the case will chamber as long as the OAL is correct.

 

[Tony Z]

Thanks CW308! My OP may not have been that clear, and my terminology may not be correct, but the intent of my question was "is there a case gauge into which a loaded round could be entered to determine is reloaded rounds are made within specs".

I've been reloading since the late 70's and on two occasions, I've had my reloads not enter a chamber. The first occurrence was in the early 80's when I gave my father some .270 rounds for his Model 70, that I had worked up in my Model 700. Though the rounds fired very well in my Remington, they would not chamber in his Winchester. The second occurrence was about a month ago while working up loads for my .357 Henry. The cause of the rounds not chambering (felt a bit of resistance and have learned years ago to not force anything) was due to my cast bullets being a whisker oversized and quickly cured by running the cast bullets through my Lyman cast bullet sizer. In thinking through the .357 issue, I believe it was a combination of a slightly oversized bullet that caused a bit of belling of the case when a crimp was applied. Interesting thing about the crimps: First rounds were made in a 1980's set of RCBS dies, with a roll crimp and would not work. The rounds that did work, were loaded in a 3 or 4 year old set of Lee dies, that had a much milder crimp (I have multiple presses and at one time, had one press set up for .357 and a Lee Turret set up for running lots of .38 Specials. I used to cast many bullets, and admittedly some of the casting combo formulas were whatever was on hand: sometimes wheel weights, sometimes just old hunks of pipe and once lead taken from an E-ray room).

 

[cw308]

TonyZ on rifle rounds resized F/L sized to the book setting for OAL , some rifles have more or less free bore before the bullet hits the rifleing, that's why store bought rounds will fit in any rifle. As for auto, once the case is belled when seating auto it shouldn't be a roll crimp but a taper crinp . Pistol is a roll crimp holding bullet tighter so it wouldn't slip foward causing cylinder to jam . a roll crimp on a auto would put a slight bulge in the case causing feed problems. Taper on a auto , Roll on a revolver. Your case gauge for 45 auto should pick up the problem, if you used a roll crimp on your 45 auto before feeding into your chamber. I haven't reloaded pistol or auto for for awhile, I'm a benchrest rifle shooter, but I do remember what could cause problems like yours. I try to keep it simple with out all the other technology. Hope I helped. Chris