October 2, 2017, 04:11 PM | #26 | ||
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Longer than: The chamber is .016" longer from the shoulder to the bolt face than a minimum length/full length sized case. When I size cases for that chamber I adjust the die off the shell holder .014" and then size 280 Remington cases to 30/06, with that adjustment I get the magic .002" clearance. There is a most interesting story among old reloaders on how the rifle got the long chamber. There were a few old smith that got their noses out of joint and then got all snarky. F. Guffey And then there is above and below, I choose to call the case head that hangs out beyond the end of the gage 'case head protrusion' cases fired in my rifle with the long chamber have .011" case head protrusion. For those reloaders than can keep up they remember to add the case head protrusion to the length of the case when trimming. Quote:
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October 2, 2017, 05:24 PM | #27 |
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Mr Guffey:
Isn't that what I said--that the case head should be flush but if it protrudes outside the gage, the indication could be a long chamber. Today I had 24 Federal '06 cases fired in a Garand and I took the time to gage each case while sizing to see if it revealed anything practical. Cases first checked in the gage before sizing--a few dropped in with no resistance and dropped right out again. Most required a slight shove into the gage as would be expected. Two or three had burrs around the rim that prevented easy entry but the burrs were filed off and entry was again easy. After sizing all cases were again gage checked and all fell in and out again very easily as would be expected. All case lengths fell between the upper and lower steps at the neck, right around 2.484 case trim length and required no trimming. They had been trimmed once before. So, was anything gained by doing that experiment? Not hardly. The case head burrs if left unattended would not have interfered with chambering due to additional chamber clearance. But I have had other fired cases that were difficult to insert in the gage due to increased circumference and that could indicate excessive chamber expansion.
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October 2, 2017, 05:38 PM | #28 |
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Anybody with an internet connection can put out incorrect and confusing information.
In the context of the Geometric Dimensions and Tolerances on Engineering Drawings A DATUM is a THEORETICAL plane,line,point,circle,etc. It is the starting or anchor assumption for the dimensioning scheme. Remember,THEORETICAL. You may buy drawings or make sketches...but a datum is not a thing. Now,the flat bottom surface of a part may be designated as a DATUM on the drawing. No problem. We may use a very flat granite surface to SIMULATE the DATUM. We can rest our part on the granite and measure from the granite surface. That is how it is done,but by definition,the granite surface plate is NOT the datum. It simulates the datum. Your case gauge is not a DATUM. It has a hole tha more or less SIMULATES the round circle of the SAAMI diameter that defines the theoretical DATUM circle. The gauge is not the DATUM. On the part being measured,there is a DATUM FEATURE. It may be the flat bottom of a part. It may be the shoulder of a cartridge case. It's real form will be imperfect. The flat bottom is not perfectly flat. The brass shoulder is not perfect. What we measure from is how the Datum feature contacts the simulated Datum ,be it a surface plate or your case guage. Feel free to research and verify what I just told you. Search "Engineering Drawing Datum" or GD+T DATUM. I would copy and paste but that copyright thing... Nothing personal,Mr Guffy,but ego does not justify confusing folks who are trying to learn something serious. Condor Bravo,you are doing well.Be aware Garand and other semi auto brass may well get some stretch after unlock. Case length and chamber length may become disconnected. You are correct about diameters on a typical bushing gauge designed to check length.You cannot gauge length and diameter at the same time with a bushing gauge.You must have diametral clearance for the gauge to measure length. A "plunk"gauge is a different tool with a different purpose. Mr Guffy,I must confess,your post #6 is good. In 9mm,all it will tell you is whether your case length is to spec.Nothing else.It IS NOT A PLUNK GUAGE. It was never intended to be. The diameters are larger than a chamber. Your bushing case gauge will tell you if your shoulder bump back puts the case to SAAMI length.Between the steps. Its great for that! Check! With the gauge and case head on a flat surface,if the neck protrudes,its time to trim. Check! NOW,we get fancy !! Once you,by whatever means,establish THE perfect head to shoulder length for YOUR rifle.....like .002 for a bolt gun,and .004 or .006 or whatever for a semi auto...Are you ready? Drop it in your gauge and measure over the gauge and your case head with your calipers, with your calipers over the ground in step. Write that number down. A year later,you can set your sizing die to give you that measurement over the case in the bushing and BINGO! Same head clearance.Just be aware if your case neck protrudes this won't work.Trim it to sub flush. Me,I absolutely do NOT think they are useless. I think a lot of folks do not know what they have or how to use it. And some bellow "Unnecessary! Waste of money" rather than I'm a newbie,how do I use this?" Guess who quit learning long ago? Guess who learns something new every day?. And who do you want to listen to? Last edited by HiBC; October 2, 2017 at 06:27 PM. |
October 2, 2017, 06:30 PM | #29 |
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When I got into reloading you used your rifles chamber as your gauge. The truth is , a round may easily fit the "case gauge" but not chamber in your rifle. I just use the rifle to make sure they chamber. But that's just me.
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October 2, 2017, 06:46 PM | #30 |
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HiBC
Good point, semi-auto case elongation not necessarily related to chamber length. Thanks for that update.
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October 2, 2017, 06:46 PM | #31 | |
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Quote:
One thing that helps is to control how much "head clearance" you get when you set the shoulder back. In a bolt gun,.002 is regarded as ideal.In a semi,more is required for reliable full lockup. Most of this is about measuring for this fine tuning. Yes,you can make ammo without. Clearly,the gage was never meant to represent a chamber.It does not. It measures where the shoulder is...in loose terms,for "headspace" purposes.(wrong use of the word "headspace) |
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October 3, 2017, 10:35 AM | #32 | |
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And now Wilson is making a gage that fits the bottom of the case gage, one more time; I have always used a straight edge with a feeler gage and or a flat surface. F. Guffey |
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October 3, 2017, 01:40 PM | #33 |
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I have a flat black granite block with a vertical post. Commonly called a compatator stand ,on my reloading bench .It has a dial indicator attached.
I can put a bushing case gauge on the plate,and zero the indicator to either the high or low gauge limit,as I choose. So long as the cases do not need a trim,I can easily get an accurate read of the case head relationship to the gauge. You can do pretty much the same measurement with calipers. The comparator stand is more efficient for qty. You can also log a die setting as "Low limit plus 0.003 gives .002 head clearance in Win M-70 .308,Low limit plus .005 gives 0.004 head clearance in the AR-10" If I want to get fancy,I can even set the little tolerance pointers on the indicator face. I can check a lot of cases fast. I have this stuff due to my trade. I have set up for so many inspections this stuff is second nature. Not every Handloader needs the setup. But if you find the idea interesting,check e-bay for "comparator stand" |
October 3, 2017, 02:38 PM | #34 |
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Yep, again a simple question gets answers steeped in advanced reloading theory and unnecessary "facts". Then the thread becomes a pi$$ing match between "expert" reloaders on who knows more than the other (one old timer is really bad at this, explaining, ad nauseum, the finer points of cartridge and chamber design).
For the OP; K.I.S.S.!!! No you don't need a gauge to see if your ammo will chamber, your barrel is good for that. If there is a chambering problem, then find a tool for troubleshooting and correcting the condition, no need to load yourself down with more tools than necessary. I reloaded several years just F/L sizing my brass and never had a chambering problem. After you get a good foundation on reloading and want to "improve" your reloads, then get any tool, gauge or book you want, but for now until you get a good handle on reloading, stick with the basics and K.I.S.S. ...
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October 3, 2017, 03:45 PM | #35 |
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Thank you all for the replies. Very helpful information.
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October 3, 2017, 04:48 PM | #36 | |
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Brass life was not a consideration, In its crudest form,that was reloading. It met my needs. For a few rounds of decent ammo,a Lee Classic set and a hammer will do. I fully respect those who RELOAD to make recycled ammunition that is safe,accurate,and meets their needs. This can be done very well with minimal equiptment I believe you are right,as far as that goes. But there are also Handloaders. They are after something more than a good replacement for factory ammo. No one has to go the extra,but the Handloader deserves respect,too. There is nothing to be gained from criticizing someone who uses a bushing gauge to tailor head clearance. Yes,the water does get muddied up .It is confusing and distracting. I also notice it seems like 95% of the posters have an emphatic opinion on case gauges,and about 20% of them know what the tool is designed to do or how to use it. Example: The word Datum is thrown around as a term of mystery and confusion with NO supporting text. Its the property of the keeper of knowledge. I had enough of the misuse of the word and the silly,confusing game.,and took the time to correct it. You may scoff. Many know too much to learn.But I'll bet the OP,hungry for the answer,learned about his gauge and its uses. I treated the OP and his question with respect. Last edited by HiBC; October 3, 2017 at 05:04 PM. |
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October 3, 2017, 11:34 PM | #37 | |
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October 4, 2017, 12:51 AM | #38 |
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I make no effort to change Mr Guffey. Not my job.
I know how to read a print.I know what a Datum is. I shared the knowledge. More people know Truth. And hopefully,more people understand the bushing gauge. |
October 4, 2017, 08:28 AM | #39 | ||
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Quote:
Quote:
I made a one legged stool, the one legged stool saved a lot of lecture time. I never had to accuse someone of doing something and then waste time listening to them denying it, they would wake up and say "What happen?". F. Guffey |
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October 4, 2017, 08:43 AM | #40 |
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I was at a gun show when I said to a dealer "DATUMS!", he claimed he did not have any datums, the shopper ahead of me ask "Where?", the shopper behind me ask "What does a datum look like?". I purchased a box of what looked like junk to most for $5.00. Basically I purchased a box of holes, the holes were in plates, bushings, case holders for tools no one had ever seen nor did they know what they fit, and a lot of it was home made.
F. Guffey |
October 4, 2017, 11:17 AM | #41 | |
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Quote:
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October 4, 2017, 12:33 PM | #42 | ||
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Quote:
Quote:
F. Guffey |
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October 4, 2017, 12:49 PM | #43 |
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Mr. Guffey is a man unto himself. I just wish we had more like him that have the knowledge that he has.
If you don't believe me, ask UncleNick. |
October 4, 2017, 02:42 PM | #44 |
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Mr Guffey referenced a digital height gauge.I have a Sylvac digital height gauge.It compliments my black granite surface plate,my Harig surface grinder,my Harig fixture,my Browne and Sharpe magnetic Vee-block,my Ingersol-Rand Radius and Angle Dresser,my Sin plate,
My precision angle plate,and mt Hermann Schmidt toolmaker vise. And I have decades of experience using such tools. I'm relatively well tooled for a home hobby shop. I just brought home my South Bend Heavy 10 Navy Signal corps lathe,(3 jaw YuasaAccu-chuck,4 jaw,5-C,Aloris,taper attachment.) It had been in my buddy's shop,he has the Bridgeport.We were a team. He wanted a bigger,more rigid lathe.I found him a well tooled 15 in by 30 Regal LeBlond For my own shop,I still need a mill,an optical comparator or toolmakers microscope,and a heat treat oven. But all in good time.I have access to a Bridgeport. None of this has anything to do with reloading. I do know about setup,measuring,reading prints,....etc. And Datums I have no doubt Mr Guffey has knowledge and experience. He never hesitates to tell us so. My problem is ,for the folks looking for answers with a serious question... His answers seem to come down from a very tall stool,clouded in pipe smoke ,shrouded in riddle and mystery. Unless you already have a very clear understanding of what he is lecturing on,you will likely be quite confused and understand less than what you did before.By definition,the OP with the question will NOT have the background and confidence to make sense of Mr Guffey. While I believe Mr Guffey has a great deal he COULD offer,it gets lost in the murkiness.It transforms from Gold to mud. Last edited by HiBC; October 5, 2017 at 02:27 AM. |
October 4, 2017, 04:00 PM | #45 |
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HiBC, it concerns me that you are so angry, I was watching the news when I was horrified by the act of one angry person. I have guns, when law enforcement started digging into the shooters life I could not believe the picture they were painting looked like me with the exception of being a millionaire, I do hot have any high capacity magazines nor do I own a black rifle.
The fastest rifle I own that is not a 22 is a 1905 Ross, it is like an M1 Garand without the gas and it is very accurate when shot slowly. F. Guffey Last edited by F. Guffey; October 4, 2017 at 04:01 PM. Reason: remove n |
October 4, 2017, 04:31 PM | #46 |
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Wow! I'm out of here. DATUM!!!
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October 4, 2017, 04:42 PM | #47 |
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No anger at all,Mr Guffey.
Anger rises from unmet expectations. I do not expect anything else. The anger is your illusion,or attempt at manipulation. You own that.And I think it is a loathsome cheap shot for you to exploit the tragedy in Los Vegas as you did. I'm just plain speaking. I'm happy. |
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