Measuring for Pressure
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- Опубліковано 26 вер 2024
- “Today we are going to talk about measuring cases.”
An update on measuring cases, as there have been questions I want to address, though there is also a video on Patreon on this subject
This video goes into further detail.
This method of measuring for pressure was developed over 70 years ago by the late Vernon Speer. I’ve not found any better way to do so.
Sit down, take notes.
Whether you have a 1 inch tenth micrometer or a flat anvil micrometer, Randy instructs on the best method for measuring cases, rimmed or unrimmed, magnum or not, it is all done the same place, in the same way.
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Thanks for a valuable piece of information that will further improve my reloading abilities. It's rare to pick up good information from people who know less than you do, so I look to those who know more. By accumulating that knowledge over time, it gets harder to find those who know more... but such as yourself, those people are out there so I appreciate you passing down this legacy of knowledge.
Finally, a man who shares usable knowledge. Thank you so much Mr. Randy
I am blessed and very greatfull that you are willing to pass down such valuable information to us, other people make you pay big money to learn the things I have from your videos, thank you sir for you're time and knowledge!
You are truly a wealth of information Mr. Shelby. God bless you for passing down your knowledge, to the next generation. I am most grateful. Merry Christmas Old Timer.
You Sir, you've absolutely made my progression in handloading so much more exciting & enjoyable through sharing all your years of experience & knowledge with us.
Thank you & wishing you & your family a wonderful holiday season 😊 from 🇨🇦
Thank you for sharing this information. For those of us who can't find a teacher - this is an invaluable experience.
Thank you so much for sharing your wisdom. “An accurate rifle is interesting” RS
Indeed it is, we appreciate this 🙏🏽
We have been measuring case head expansion for years! I have held mine to 0.0002" expansion. I have used a blade micrometer to measure the case head as I fine it more accurate. I am glad you are showing how it's done. Mr. Speer told us 0.0001" was max and others have said 0.0005", I have settled at 0.0002", I also use a 0-1" blade from Mitutoyo Digimatic Blade Micrometer, 0-1" accurate to 0.00015". The other thing is to be careful that you are not measuring ahead of the case web where some cases expand at that junction. If I remember right the, it was in Handloader Magazine back in the 70's were I first came across the method.
Thank you, Mr Randy, keep the great information coming
This video describes exactly how I was taught to hold and use a micrometer nearly 50 years ago while working as an inspector for a precision machine shop in the automotive and heavy equipment industries. I was also trained in layout inspection for the jigs and fixtures used in production and final inspection. This is THE way to hold a micrometer.
Thanks for watching and taking time to comment, with CORRECT information.
I'm sure that using a micrometer holder is mostly for the OCD among us. However, the fact that the yoke grows with the heat from one's hand is undeniable, significant or not. I was taught to use it to tell when a mic is properly zeroed. When the one inch standard is held between the anvils and after holding the yoke for a bit, it drops, that indicates correct calibration. Of course, test piece and tool need to be at the same temp, etc. etc.
Love to listen to this guy person can learn a lot from him
You are a treasure Randy. Thank you for sharing your knowledge.
Wow, thanks
Great video I learned something new. Always watched for pressure signs but never new how to measure it. Thanks.
First time I heard about checking for pressures.....Thanks you for all you do!
Excellent information & much appreciated.
Casework is the vital foundation of the whole shooting match.
Just maybe the best one yet, randy. Thanks
Thanks Randy,
I have used your technique to bring my 6.5 SE into the 21st century shooting 100gr bullets
I only came close to head expansion expansion with faster burning powder AR 2206H. It has taken a while to get to the AR2209 via 2208. Whilst the faster powders took a lot more efffort to get to 3200fps, 2209 made it easy almost within book parameters . Your information and comments proved extremely helpful 👍🏻
Like I said Randy sir you have forgotten more than I do know and ever will know thank y’all GOD BLESS
Thanks for sharing Randy. I hope more people listen to what you are saying.
These are pearls of wisdom! Thank you for sharing from Greeley, Colorado!
I learned this method from the Hornady 2nd edition manual. I purchased a blade mic because it's hard to measure a round surface with the flat anvil of a standard mic. The small balls like Randy has would be nice too.
Keep putting it out there thank you!
Vern Speer used a collection of factory rifles to determine loads.
1. Factory rifle chambers vary brand to brand, model to model and as the reamer wears.
2. Cases vary brand to brand, also in volume and hardness which changes the case thickness where you are measuring.
3. If you fire a soft Winchester case with more volume in a sloppy chamber it will record more expansion and not be an accurate measure for pressure. Likewise, many factory rounds expand a lit because they are undersised to fit any sized chamber
4. Modern pressure testing has determined that pressure signs appear at around 70k psi which is already past factory maximum SAAMI pressures.
Thanks Randy😅. I have a digital micrometer with interchangeable ball, flat and point measuring ends. I often wondered why it was designed in such manner. Now I understand why and how to use my micrometer even better. Once again, Thanks you!
Thank you for the great talk
Good evening Randy and to your lovely wife to.
Real sound advice and very experienced with rhe subject
Very informative advice. Thank you Randy.
Thanks for sharing your experience and valuable information with us!
Thank you for taking the time to teach and pass on your knowledge.
Fantastic information and instruction. Thank you. 🐕
Great video Randy, thanks for sharing your vast knowledge, you are the Master Technician.
Thank you for sharing your incredible knowledge.
I love to set in my junk room my wife calls it and listen to the radio and load some rounds. Randy sir this is a very good video all of your videos are great. Thank you for sharing this very informative video with us great job. I learn something from every one of your videos I can catch. Merry Christmas to you and your family sir and Happy New Year GOD BLESS y’all Amen 🙏
Thank you for sharing your knowledge
The old ways are the best, thank you for sharing!
Hi Randy,
Thanks for passing on life long info, Forgive me if I missed the answer,. How do you deal (measure) with 2nd, 3rd, 4th fired brass ? if you use it for further load development? Or Is it just once testing from brand new brass only?
Thanks, The Windsock.
They are measured the same way and for further expansion. When it does, you go to new cases.
Thanks for watching.
Great information thanks so much.
Thanks for sharing your knowledge and keep your videos coming please.
Thanks Randy for sharing your wisdom. God Bless and Merry Christmas
Thank you, Sir! I have ALWAYS done it that way, but I limited my loads to 0.0003" for the first firing. Also note that brass work hardens, so I always check the 2nd and 3rd firings, too, just to measure that those expand LESS than the original 0.0003". Having said all that there, I then back the load down 0.5 to 1 grain to check for best accuracy. I Usually find that accuracy point at 0.5 grain below the maximum load. Oh. BTW, I have yet to have any game animal thank me for the 30-50 f/s slower impacts... It washes out over range variations anyways. Merry Christmas and a Happy New Year! Jerry
I know one thing since I learned how to measure my brass I was amazed at the greatest groups I can shoot.
I love Randy!!!
The case head measurement system produces very low grade information. It is possible to overcome this by measuring a prohibitively large number of samples, but that just isn't practical. Anyone who thinks they are going to get a correct pressure measurement by measuring a few case heads is dreaming. It has been part of the lore for a long time, and is thankfully finally starting to be abandoned. It is dangerous and should not be used.
The etymology of micrometer is greek and actually preceeds the metric system.
It simply means, "small measure", not a millionth of a meter, micron. or micrometre.
I am also a machinist. Not as old as Randy but 48 years in shops both commercial and academic.
Most of those shops were climate controlled to prevent errors due to expansion or contraction of stock due to fluctuations in temperature.
One of those shops is a contractor to NASA.
Every professor and every master machinist or tool maker using a hand held micrometer that I have ever known used it as Randy demonstrated.
But I am old. Is there something new under the sun that I have missed? (Happens more and more).
Can you share a source?
Every second year machinist knows that the thermal expansion coefficient of steel is approximately 0.0000072 inches per degree Fahrenheit or about 12 micrometres (see what I did?) of length per meter of stock at +1°C.
They also know that it is a range.
No hand held micrometer can even see those differences.
Cheers!
Randy sir I don’t doubt your wisdom one bit and I’m sure you’ve forgotten more than I will ever know. I’ve been loading from when I started till now probably 35 years.
Very interesting.
Great video. Just looking at primers and looking for extractor marks/heavy bolt lift doesn’t tell the story. Your method does. Using the micrometer is more accurate and gives feedback before something extremely negative happens. Thank you.
Awesome info! Thank you!
Thank you for your videos. My observation this year with Hornady 7PRC brass was impressive in a very negative way. Even with first reloadings and minimal powder charges, the primers basically fell into the pockets. Even some of the once fired brass from factory ammo wouldn't even keep a primer snug. This is the first year I've ever handloaded Hornady brass. It won't happen again
Hornady brass has done this with me in 6.5creedmoor, 6.5PRC and 300WM. Norma brass fixed it.
@@albertlemont5471 I like Norma brass and use it a lot. Also Lapua, ADG, Peterson among higher end cases. Never had issues with Fed, Rem, or Winchester brass. This year I'm new to Starline and so far it's excellent. Would like to try Sig Sauer
Same experience with Hornady brass. It's junk. I use Peterson brass.
@derekmcmurry4263 I have some sig 6.5 creedmoor brass. So far so good with 3 stiff loads of 4350 and Hornady 120cx at 2950fps
Thank you Randy
Found nearly 30 years ago. Use a specific case brand and check all by weight and detention. Use a quality reloading manual and follow with caution. Have found that small cases such as .22 hornet , .17 hornet. .17 fireball , .221 fireball are very sensitive to pressure spikes between different case manufacturers and powder manufacturers even from one lot to the next . I love them but always keep safe in reloading them. Tight tolerances spike pressure. Fact. Use discipline and control over how you reload ! Blessings to you all and keep safety first!
Greatly appreciated..
👍👍
I have a Starrett micrometer, hopefully that is accurate enough.
A lotta years ago, I read about this measurement, but the recommendation was to measure the expansion of a new, factory load and try not to exceed that expansion. This doesn't help me much as I seldom fire factory ammo, sometimes because it is no longer produced. My actual question is whether the 0.0005" limit applies to each firing or first firings, only. Once a case has been fired three or four times, does a 0.0005" incremental head expansion mean the same thing as it would on first firing? Or, does arriving at 0.0005" growth from new indicate max pressure has finally been reached? I bought a blade mic for taking this measurement.
What is the increase in speed using a 309 jacketed hollow point bullet in a 308 barrel? i am loading a Hornady 30 cal 90 gr XTP #31000, a pistol bullet, with CFE/BLK 21.5 gr in a Schilen 30 tapered match barrel 16" long in a 300 BO No book i am going slow very accurate/small game. I shoot 100 yd target, a target shooter from Boy Scouts who used to hunt. So far have loaded and shot 2300 rds from 90-200 gr with 1 hole loads with Speer 130 gr large hollow point , varmint with CFE/BLK and IMR 4227, need drop tube. Book says 1996@28200 with IMR 4227 about 38.700 I to go a little less ant a 32-40 Everlasting. wasted 30 min not trimming brass loaded some cases shot over a hundred times no need to trim.
You need to use a chronograph to measure the increase. "The book" information is a guideline. All rifles are individuals and will get differing results, even with the same load. You won't know for certain what you and your rifle are doing without a chronograph.
Thanks for watching.
Everything Randy is explaining is stuff I was taught by my father. Sadly, todays younger generation have dropped it on the ground and left it to spoil. So sad.
Just a little clarification. Is that half thousandth diameter or a half thousandths radius. About the 6 minute mark I heard this was a radial measurement?
.0005 is the diameter, not half the diameter, or I would have said so.
Thanks for watching.
@@TheRealGunsmiththank you. Someone else replied and said the opposite, but that reply is gone now. Thanks for the clarification and have a great Christmas 🎄
Randy I have a question. I am getting into reloading for myself. Have had others reload my ammo for me in past. Does this method need to be done on new brass, full length resized brass or will it also work on a fire formed piece of brass if I wish to just neck resize? I plan to do my loads from factory fired brass.
You measure new brass and again after firing each time.
Thanks for watching.
@@TheRealGunsmith I bought a 100 rounds of Norma ammo to shoot and use the brass from since it was much cheaper then getting new brass. Also I couldn’t even find new brass for 270 win from Norma.
So must it be new brass or once fired work as well?
Randy what is your thoughts on a tight chamber holding the case head expansion to a minimum until that pressure far surpasses what a factory rifle would have exhibited for the maximum allowable case head expansion?
A tight chamber does not hold expansion to a minimum. Tighter chambers build pressure sooner as they are tight.
Thanks for watching.
Since metal expands with heat , do you wait to measue until the case has returmed to room temperature? Or can
you measure it wile still "hot"?
Heat is of no concern in a bolt rifle. I've never had a case out of a bolt rifle be "hot".
Thanks for watching.
Thanks for the knowledge! Can this method be applied to semi automatic pistol ammunition?
No, it can't.
Thanks for watching.
A writer is a writer not gunsmith. Love it.
So you’re saying measure in between the labeled case head rim portion and the start of the wall of the case ? Like down in the groove that the extractor falls down in? I’m assuming measure that part because that’s most directly in relation to the primer pocket? And assuming that because you’re using pointed micrometer jaws ? Am I picking up what you’re putting down?
I’m fairly new to this and stick to manual load data but would be a handy thing to know in my opinion just to keep yourself safe.
You measure above the extractor groove, the web of the case after the primer pocket ends.
Listen again.
On the head, ahed of the extractor groove, 1/32nd of an inch.
Thanks for watching.
😊I think our ole buddy Ken Waters explains it well in his books (pet loads ) vol. 1&2
Waters measured cases at the area of greatest expansion not the area over the primer
Thanks Randy…
Randy,
What should a guy do with piles of brass in various cartridges that may have been fired over pressure but were never measured at the case head prior to firing?
Can it still be used or does it go in the trash?
If I find pieces with an extractor mark on the bottom of the case should I throw those away?
Can you tell how to measure pressure using plastic gauge
No. Won't use them.
Thanks for watching.
Randy, it would help if you held up an illustration of a case, marked to show exactly where to take the measurement. Pointing with your finger does not give a clear indication of what you mean. I only use mid-range loads that are listed in the manuals. I do not experiment with hot loads, so I presume I don't need to take these case head measurements.
I highly doubt you were going to respond to this, but I really need your help!! Can you please make a video exactly how you measure your cases because I’m doing something wrong. I have alpha 308 small rifle primer brass and I am loading 42.0 -45.0 grains of varget powder. The original reading from the brass was .4682 then after one firing of 42 gr the lowest published load the reading is .4691 and all the rest are .4686-.4689. Which means almost all of my loads are over pressure. I tried to follow every bit of advice I can from you, but this subject is really kicking my butt please help. None of my primers are flattening nor have ejector marks.
We are able to sort comments that have questions and if they are legit, as your is, we answer, as time allows.
We do have other videos on YT and Rumble that may help: Case sizing in depth, Case trimming, Gauging cartridge depth, Reloading for accuracy, Brass: reloading tips, as well as 4-5 of them on our Patreon channel. You could join for one month, watch the videos, then cancel if you aren't interested in a monthly subscription.
I don't think you are doing anything wrong, by the measurements you give. Load your cases again, that you have fired and see if they expand more. If so, reduce the charge 1 grain. Not all barrels, chamber are the same. Good luck. Email me if you have further questions.
Thanks for watching.
Now with the different case styles wouldn't you measure them differently such as a belted magnum ,rimmed,rimless,rebated cartridges have different traits that are essential .the shoulder on a belted magnum may shift .also the pressures by bullet seating depth will effect case life and could aid in accuracy and remember barrel throat and freebore along with chamber may expand with high pressures after many loads have been sent through the barrel !
On a separate note, what are the draw backs of not sizing fire formed brass?
Clean prime load and crimp for hunting not bench rest??
No crimping. Size fired brass for hunting.
Thanks for watching.
I've looked at a few schematics for 45-70 cases. I don't have one in hand to check yet. The schematics vary. Some say the measurement right above the rim is .498, some say .505 and some say .506. Just for the sake of my question, and i hope it's not too much of a stupid question, but I'm just trying to learn. Let's use the .505 measurement. Would half of a thousandth more case expansion be .510?
Sorry I am terrible at this stuff.
Mr. Selby, is there a commercial micrometer available without the anvil style points, such as the one you use? Is there one you would recommend? Thank you for sharing your knowledge, i always enjoy learning from your videos!
There are many, many good ones, go to reputable outlet and find a blade micrometer in .0001.
Thanks for watching.
Can you add a link to one of these micrometer. All I see is one with flat tips. Nothing with ball ends. Thanks. I love all you videos. Very informative!
Hello, when you say the head of the case do you mean the rim?
The head is not the rim. I didn't say rim, as that is not what I was talking about. I said just ahead of the extractor groove, 1/32nd".
Thanks for watching.
If I was wanting to try a new powder in a rifle but I cannot find any reference to that powder in that caliber. How would you determine where to start with your powder charge if there's no reference?? I'm thinking lever action 45-70 30/30 calibers, using slower burn rate powder then IMR 4198.
Look at the burn rate chart and data for the caliber to come close, start conservatively and work up in 1/4 gr increments.
Good shooting.
Thanks for watching and Happy New Year!
Hi randy I have a question a little off topic for this video but I don't recall if you have a video on annealing or if you anneal you brass your thoughts please.
It would be a very, very short video. No, I don't anneal modern brass as it is done in manufacturing.
Thanks for watching.
New brass or fire formed brass?
New brass.
Thanks for watching.
I’m learning my 13 year old nephew to reload.
Would this be .0005 max of expansion?
Yes. .0005 is top working pressure.
Thanks for watching.
I'm not perfectly clear on what you're saying (after listening carefully -- twice). Are you saying that the max pressure load you should use is the one that expands a half of a thousandth -- and that a load that expands more than that is over-pressure? Also, Mitutoyo makes a micrometer graduated to 0.0001 inch, with spherical anvil and spindle. Is that the type of micrometer you are recommending? Thanks.
A better micrometer is a blade micrometer that allows you to measure with a thin blade. Mitutoyo Digimatic Blade Micrometer, 0-1"/0-25.4mm - 11-792-9 is the one that I use expensive but worth it.
@@paulnelson9907 LOL. Thanks for the info, but I don't think I'll be spending a thousand bucks just to measure case heads...
He's saying max pressure is 0.0005. You don't want to keep shooting that. Back off a half grain to full grain of powder.
Also you don't need a 1000 dollar micrometer. There's plenty of them from 60 bucks to 200 that will get the job done.
Yes, just what I said you heard correctly. Buy a spherical .0001 mic.
Thanks for watching.
@@TheRealGunsmith Thanks. Great info. I'm very eager to work with it.
If you can't understand this, I think it's safe to say quit reloading and take up golf or knitting.
What do you think about the 6x45?
Another 6mm. Good within its capabilities.
Thanks for watching.
Randy did you check with gunwerks
LOLOLOLOLOLOLOLOLOLOLOLOLOLOLOLOLOLOLOLOL
Can you recommend a micrometer
Mitatoyo
@@justice1327too expensive
@@justice1327 Type or model or Style
Pointed , rounded, Blade micrometer
Mitutoyo are tops. Blade micrometer in .0001.
Thanks for watching.
If you don't have small hands you can insert your ring finger in the micrometer. Really
Sorry I comment so much
I am a machinist, and we do never advice to hold a micrometer in such way. Why? Heat will transfer to your tool and give you inaccurate reading. You should hold it on the small, insulated area, if you do not have a micrometer holder. And why do Americans call it a micrometer, clearly you measure inches 🙂 I have used this method for as long as I have been reloading.
I worked with a carbide tool company and we held the micrometer exactly as it was shown here and we held tollerences to .0005 of an inch.
I have seen heat change tings but not att humen heat thats so little that you Will not measure that accurate.
Micro = very small
meter = to measure
As a "machinist" you should know that the measurement unit, whether inches or millimeters, is able to be micromeasured with proper devices.
Good for you, but I've worked with tops in the field for over 60 years and all have done this even a tool & die maker/machinist from Germany who worked for 40+ years with tolerances tighter than most people can even imagine.
The term 'micrometer' can be traced back to neoclassical Greece and literally translates as ‘small measure.’ Different types of micrometers have measuring ranges of between 25mm and 1 inch.
Thanks for watching.
I have worked with professional racing engines both machining and assembling. As long as he’s consistent in how he holds the micrometer it will read the same every time. The people who thought up this method obviously understood that it’s a great way to hold the micrometer consistently. We measured some parts to .00001”, and yes, temperature transfer matters, but consistency matters more. Best practices for precision in any field are consistent practices.
Can you help me I'm try to put 1000grains of IMR 4198in a 30-06 and I'm having pressure problems:0 I will call it 30-06 Weatherby >JK< Thanks for the great teaching wisdom I really listen to all your vids. Thanks for sharing your time and expertise.
Thanks! Glad you are JK!!
We appreciate your following.
I’m pausing for my comments I like Winchester brass I’ve always used more of it than any other kind of brass.
Hello Mr Selby allways enjoy learning and watching your videos. Just wondering your opinion about Norma brass vs Lapua brass? It just seems like some shooters ar religous about lapua "if lapua doesnt make brass dont load it" . Also any input on the 7prc-w cartridge it a 6.5 prc necked up to 7mm. That caliber won the worlds in fclass open and i think recent midrange as well at nationals. I think it was favored because Lapua brass is avaliable. just wondering any thoughts on these subjects, thank you and happy holidays.
Both Lapua & Norma have brass and they are very good. Lapua over Norma, is my take.
Thanks for watching and Happy New Year!
Does the micrometer have balls on both ends?
Yes, it does.
Thanks for watching.
Great information! I enjoy your videos.
I REALLY LOVE THIS MAN .