Measuring Pressure

[@KeystoneTexan]

Mr. Selby teaching class once again.

[@rt66rc86]

Randy, I learned what you are teaching here 50+ years ago and Vernon explained it well in his reloading manuals years ago! Why people choose to remain ignorant when the facts and the truth about this is starkly evident to anyone with common sense and reloading equipment, remains a mystery to me! God Bless you and yours's my friend.

[@TheRealGunsmith]

Yes, it's a mystery. Keyboard warriors figure they know more than anyone with decades of experience. Thanks for watching.

[@joshuawooledge6945]

Your concern for educating and advancing others for the benefit of all reloaders is humbling. Thank you Randy and Cathy for all you do.

[@edwardabrams4972]

Remember old Vern! He made great bullets at a very reasonable price and top quality for their time🙌 Today Speer is still one of the very best for their price bullets! 60+ years of handloading hunting and rifle collecting and after using thousands of bullets and he knew what was needed for the job of taking game!

[@marksarkaquariums9056]

Thanks for doing a second video on the subject.I watched the first one,but never quite got it 100%.Most people will listen until you say something they don't want to hear.Then they look for someone to say that doesn't matter and take that as gospel.

[@TheRealGunsmith]

Thank you. You hit the nail on the head. Glad this one clarified what you needed. Thanks for watching.

[@brianwhitney2075]

If folks would just listen to this simplified advice about an important issue they would save themselves from themselves. Thank you, Randy and Cathy,!

[@daveysac]

Randy, have you considered offering a gunsmith course for the next generation? There is absolutely a need to protect and share the knowledge to the next generation….. sign me up!

[@TheRealGunsmith]

It's come up a time or two. For a multitude of reasons, in person classes are not an option for me to teach. Trinidad State Jr college, where I learned, has a 2 year and 3 year course. Not the same, I know, but they are producing good gunsmiths. Thanks for watching.

[@adamscott-young1216]

A timely reloading tip. I am on several social media groups and seeing posts every day ,blown primers, ejector marks, my bolt is sticking, cratered bolt faces etc .All brass is not exactly the same in its metallurgy and if you stick to the methods that Randy has described (a viewing of his case sizing video too) you will end up with spot on loads that are safe and repeatable for that particular brass in that particular rifle.

[@JimParvin-o9e]

Thank you for repeating this aspect of handloaded ammunition. I'm still keeping every single video that you make to keep it in my video library as far as all the things that you know about guns and handloaded ammunition. I put my trust in your extensive experience. Thank you very much, Mr. Randy Selby and God bless you and yours. J.B Parvin

[@richardkramer1094]

Shars sells a Mititoyo 1” spherical end micrometer (SKU 115-253) for this purpose at $133.00. It is what I use every time I’m working up a load and compare a fired load. For those interested.

[@TylerKlatt-kv6xl]

Thank you from Saskatchewan Canada

[@madsloper]

Thank you for passing on your knowledge, I've implemented this measurement into my hand loading process. Thanks for keeping us safe.

[@TODinWY]

Randy, the amount of knowledge you have accumulated over time is nothing short of astounding.

[@pabloco091]

I figured it out from the other video, thanks again for your recommendation on a micrometer 👍

[@jessejones3616]

Thanks Randy! When I started reloading I use your teaching as a guide to work up loads. Was a tremendous help.

[@normanmallory2055]

That’s very true and he is spot on with his method ! Myself I’ve used a 1” micrometer for years to measure case head expansion! Mostly in my teens I read Outdoor Life in the 50’s and 60’s always the hunting column and tech tips ! As the years past I took the Rifle and Handloader magazine , so at this point I can’t say with certainty where I read about that method!

[@19jimbo62]

Thank you for your wisdom and techniques!

[@robbie1390]

Lots of love coming your way from Northern Alberta your videos are a wealth of knowledge have learned so much just watching and listening. Thanks for taking the time!!!!

[@scottpellegrin8]

Awesome job explaining this a second time Randy!

[@bills303]

I tried this technique you showed by removing a little brass from the rim on three different cartridges that I reload for. All three were the half a one thousandth that you described. It was very satisfying to get that result.

[@adamwright4969]

Thank you Randy , i always value you4e information that you graciously take the time to give us.

[@N5KDA]

This information was also in the Hornady Third edition reloading manual. This is easy to do with a blade micrometer.

[@puppy1876]

Thank you Mr. Selby for revisiting this subject & reviewing the proper use of a micrometer for this technique. Very clear and concise. Well done Sir. Been rolling my own ammo since 1975. Thanks again for sharing your knowledge. Best regards, Paul

[@HotRod7mm]

As a man getting back into reloading after a number of years without appropriate room the the equipment, I greatly appreciate the info your sharing. It’s something I can share with my boys as they get into hunting/firearms in general.

[@onpsxmember]

Interesting, thanks for sharing. If one is measuring small objects with a micrometer, a fixture is a good idea. The hands heat both up and the reading is more consistent cause the viewing angle stays the same. Even with the isolation area to hold onto, that can change within 0.002 mm ( 0.000079 inches). I'm sure you know about that, it is just for others that might not. It sounds viable to me IF one is consistent in measuring the cases including measuring failures and if the case material is consistent. With enough data points and absolute control of the case material and forming in house, one could even build a decent pressure approximation and throw in a FEM model as well if I'm not mistaken.

[@disturbedmaynard3873]

Going to finally have more time to dedicate to hand loading soon. Good thing I hung on to the machinist tools when I got out of machining work.

[@docholliday1588]

Thanks Randy,love the videos. hope you and your family are doing well.

[@TheRealGunsmith]

Thanks! Doing well, just very busy, so thus the fewer videos. A few I hope to get up by tomorrow, barring any more unseen interruptions! Thanks for watching!

[@jrhunt414]

Great info. Using yield information to predict max pressure without needing to actually know the pressure. Just making sure you don’t over yield the case because that’s what really matters in most bolt guns.

[@dme031990]

Thank you Mr Shelby.

[@thomaspaine5091]

great information Randy thank you

[@paulhazel5754]

thanks again, love every vid. take care you two.

[@Jack-ur5or]

As always Randy is rite on point…again! Best wishes from the west end of your state!

[@joelclark2130]

I learne some thing almost every day. My you live as long as you want kind sir.

[@troycrum9294]

Thank you.

[@michaelguerin56]

Thank you Randy and Cathy a.k.a. The Boss. Honest information can be rare. I have always been a wee bit doubtful of measurements forward of the case head BUT getting to the heart of the matter was not easy. The middling to poor-especially Sierra-Tables of Contents in Reloading Manuals do not help. The gross arrogance that I encountered when I pointed this out to Sierra was disappointing but not as disappointing as the thoroughly dishonest response from Hornady when I advised that their stated Maximum Overall Length for the 8x57 IS with their then new 195gr flat-base bullet was unachievable. I still have the printed copy of that garbage response with the employee’s name.

[@jfess1911]

As mentioned, this method does not measure the actual pressure, it merely shows where the yield point is for a particular piece of brass in a particular chamber. That is fine for a strong action with plenty of safety margin, but some brass/chamber combinations can take very high pressure before significant case head expansion happens. In a recent Ultimate Reloader episode, a 308 was pushed to over 100,000psi with Alpha munitions brass. They were at over 80,000psi before they got over half a thousandth case head expansion. On weaker actions like lever, pump, or semi-auto, the absolute pressure is indeed important. Those bolts have less of a safety margin and will break if the pressure creates too much backthrust. This is more common with some setups, like a 6mm ARC or 6.5 Grendel, where the AR15 bolt strength is what determined the SAAMI 52,000psi max chamber pressure*. A number of people have broken bolts with loads that did not show pressure signs like case head expansion. When the chamber and cases are clean, the brass sticking to the chamber reduces the thrust against the bolt. If there is some oil or lube on the case or chamber, or if things get wet from dew or rain, the bolt sees closer to the full backpressure and is more likely to break with an overpressure round. * The brass itself can handle higher pressures. In fact, Hornady publishes two sets of reloading data for the 6 ARC. The "gas gun" max pressure is 52,000psi and the "bolt gun" data is 10,000 psi higher.

[@MichaelRandall-f1o]

I've reloaded now 24 years. The Lee and Lyman manuals show pressures. And are the First go two manuals I use first. I've only reloaded 3 calibers to max pressures. .44 mag, 7.62x39, 6.5 Grendel. The Ruger Black Hawk 6 gun, AR 15 in 7.62x39, and 6.5 Grendel were the guns used. my winter loads in .243 win. I don't shoot over 70 degrees temp out side. Don't shoot a 45acp that a bullet has been set back in the case from a stove pipe. The primer blew out... always work your loads up from the start load. You are the only one responsible for your loads.

[@robertskowronski2923]

That was a wonderful video! I shared it with my buddy.

[@jaydurtsche2569]

Well done!

[@geoffreyanderson4456]

Thank You Sir!!!

[@joeallbright3245]

Randy should have PHD after his name based on the precision yet common sense approach he takes to explain the details that matter. Thank you Sir for sharing the information and experience of a life’s work!

[@iamnobody9542]

Oh. I have to add this here... You remember those yearly 'reloaders bibles'... This one writer had a friend who he called "Shrapnel"... There was a foto of Shrapnel standing in front of a wood fence all burned black and his clothes shredded and face blackened, holding a rifle with the barrel split opened 4 ways like a banana peel... I wish I still had that... Jerry

[@stevebrown8299]

Thank you Mr. Selby. Enjoy videos sir. Very good information.

[@michaelguerin56]

Thank you Randy. Honest information can be rare. I have always been a wee bit doubtful of measurements forward of the case head BUT getting to the heart of the matter was not easy. The middling to poor-especially Sierra-Tables of Contents in Reloading Manuals do not help. The gross arrogance that I encountered when I pointed this out to Sierra was disappointing but not as disappointing as the thoroughly dishonest response from Hornady when I advised that their stated Maximum Overall Length for the 8x57 IS with their then new 195gr flat-base bullet was unachievable. I still have the printed copy of that garbage response with the employee’s name. Cheers from NZ🇳🇿.

[@samstewart4807]

Hi Randy, When I saw your first reloading video ( use of mic) I thought wow. Until now, I never would have thought to use 2 balls- AND you did not not tell us to use 2 balls. (lol some people need to be told what 2+2 is) For years I used 1 ball to measure engine bearing thickness. Until you made this video, I would not have used any balls to measure case expansion. Now that you explain it ( 2+2 really is 4) it makes perfect sense. Using two balls, you can pinpoint any spot on the case( in relation to the END of the case) and get an accurate measurement of THAT spot. I will bet that most? people who tried your method used no balls. (That explains their critique of your method) I hope everyone listening now understands WHY your 2 ball system is the perfect/correct way to measure case expansion. I certainly do. Why is always so difficult to see the forest through the trees????

[@tobinlakeguideservices]

Like the first video on this subject, great information

[@billcarlson852]

Thank you. I listened, message received AND WILL BEGIN TO IMPLIMENT😊😊😊😊😊

[@misterlewgee8874]

Appreciate your content. I wonder if case head expansion may vary from brand to brand of brass with different metals and case head or web thickness.. However....this is perhaps not too significant if you keep the expansion to under half thou to save th primer pocket from expanding..

[@gregrehmer9069]

Oh, good video!

[@jwdundon]

I am at work so I can't watch this video right now.... BUT, after work, I am looking forwards to watching this one. I am having a BITCH making a sub MOA cartridge for my 300 rum. 2 MOA, EASY, (1 is being a real bitch-- with a HUNTING bullet)! Thanks for the video.

[@S.A.U.1489]

Thank you for this video. I am curious, how would you measure pressure on a rimmed case like 7.62x54R, 30-30, 30-40 Krag and so on? Thank you for all your hard work.

[@TheRealGunsmith]

These are all loaded under pressure for the procedure to come into play. Thanks for watching and God bless!

[@willemgreeff4475]

Brilliant

[@thomasdaum1927]

👍👍👍👍👍👍👍👍 Thanks Randy !……..

[@joshchieka810]

Mr Shelby thank you for going over this again! Does this same method work for all cartridges like pistol (475 linebaugh and 454 casull) our just rifle?

[@JohnDoe-zr8tq]

If you spelt his name right, maybe he would answer you

[@TheRealGunsmith]

No. For rifle cartridges. Thanks for watching and God bless!

[@robbieodum9345]

Randy, thanks for all the info and I love your videos. Simple enough method. Question, could you recommend any specific depth micrometers that would work good out the box for this, and/or show us how to modify the Anvil like you mentioned you did yours? That would be awesome!

[@TheRealGunsmith]

Check with Mitutoyo. Mine are decades old, work as well a new. Thanks for watching.

[@johnnydawson7675]

Randy , good video production. Those gold fans in the background have been removed. Much better picture that way. Thanks for the video.

[@rogerray2545]

👍🏻👍🏻

[@iamnobody9542]

Amen, Bro!! But. What you didn't mention is that different lots of the same mfr brass and particularly different brands can have both different case capacities and different initial case head hardness's. Bullet seating depth also matters, as does freebore with different boolitz of the same weight by different mfr's or even different shapes of the same weight. IF you buy a large same lot # of brass & powder, and always use the same boolit the same way, in the SAME gun, this works fine! Bench resters do this all the time. But. For Wally woods walker look'n fer a buck... Not always... Oh, but he wants his bang maker to shoot like a laser... at least 1,000,000 f/s!! with several empty 20 rd boxes of any number of different mfr brass to "reload"... Good luck!! I have always reloaded the same as you. but - particularly before temp stable powders - I would always back down a half to 1 grain from that load. I also noticed accuracy was better then, too. Nor was the trajectory loss from 50 f/s less ever noticeable. Neither did any of my game animals ever complain about it, either. Good show, Sir!! Jerry

[@davealderfer8270]

Curious on your thoughts about whether to crimp or not to depending on the cartridge..

[@CharlieInglis-ps9ev]

Thanks for another very helpful video Mr Selby, in the video you mentioned that you start by measuring the new case before firing your test load. My question is does it have to be brand new brass or can it have been once fired factory brass? Thanks

[@TheRealGunsmith]

Preferably, new. Once fired, you can try it. Thank you and God Bless!

[@CharlieInglis-ps9ev]

@ Thanks for the advice!

[@MrMagoo321]

@TheRealGunsmith thank you for confirming my spotting all the BS ing going on out there (not much of an engineer statement). I can see the micrometer method being more accurate. You don't need to know the actual pressure. Some guys are actually still saying 7 prc delivers more velocity than 7 mag. I need to see his particular ammo chronographed. Just my opinion. I have been noticing there are a lot of BS ers in many aspects these days. Thanks again

[@wesleywhitworth2424]

Mr Selby, What is your view of annealing brass? If you have mentioned it, I didn't hear it. I always appreciate your content.

[@TheRealGunsmith]

No need. All modern brass is annealed in the manufacturing process. If there are companies not doing so, I don't know of them. Thanks for watching.

[@wesleywhitworth2424]

@TheRealGunsmith thank you sir! I've seen some reloaders annealing their fired brass, but I've never heard you mention doing so. If that works for you, I won't fool with it either.

[@David-bf9ux]

What is your favorite cartridge Mr. Selby.?

[@johnnash5118]

Hi Randy, Since you stated that you can get up to 15 moderated reloads; if you stay @2% away from max published velocity, is that enough to not be concerned about case-head expansion and ball-caliper measurements, perhaps limit the reloading to 10 times?

[@TheRealGunsmith]

I think you are missing the point. Accuracy is only obtained with a load, ballistic balance, where there is close or minimal velocity spread. Thanks for watching and God bless!

[@JacobRiggs-v7l]

Thank you for another video Mr selby! I’m new to rifle reloading. Do you measure virgin brass and compare it to all subsequent firings? Or do you compare first firings to second and second to thirds? Thanks again for taking the time to make these videos for all of us. God bless.

[@TheRealGunsmith]

No pressure above .0005 case expansion. Thanks for watching and God bless!

[@gregrehmer9069]

Question, I’ve been measuring case head expansion with a ball micrometer like you said, and get good repeatable measurements. I also use a go-no go gage for primer pockets. I’m loading 308 well under published loads, 42-43 grains with Lapua brass. After 6 same loads primer pockets are still tight, seemingly no or little change from new. But I find after the first firing I get + or - .001” expansion and there after .0003” or less. Does that make sense?

[@JohnDoe-zr8tq]

I don't understand how after firing your cases could be minus -0.001.... just saying

[@jbradley500]

This method is just for center fire rifle cartridges in that 60-65kpsi range i assume? Do you take brass manufacturer/hardness or diameter of the cartridge into consideration?

[@TheRealGunsmith]

Yes. use the same procedure of loading for any brass to get the max working performance. Thanks for watching and God bless!

[@robertoaragon1506]

👍

[@sbacsigadget]

What would you think about using a blade anvil style micrometer to measure the case?

[@TheRealGunsmith]

Very good. Thanks for watching.

[@mikerobinson6606]

Randy, What are your thoughts on the 35 Whelen as a lightweight timber rifle for Deer and Elk (inside 300 yards)? What bullet weight would you recommend if at all?

[@TheRealGunsmith]

200 or 223 gr. Thanks for watching and God bless!

[@sherwinstaudt1881]

👍🙏.

[@danielravenstar4051]

I am new to the idea od using the micrometer, Can u recommend a brand name and model you use, So i can start getting some hands on experience, With the same measurement device that you say works...

[@TheRealGunsmith]

Buy a 1" blade mic that reads in ten-thousands of an inch. Mitutoyo are great. Mine is decades old and works like new. Thanks for watching and God bless!

[@Paladin1873]

If the case is tapered, how do you ensure you are measuring the exact same spot each time?

[@TheRealGunsmith]

The immediate area forward of the extractor groove. Thanks for watching and God bless!

[@jasonweishaupt1828]

Looks like ol’ Ken passed on in 2017 at 100. Looks like he was a wildcatter too.

[@triggerman1092]

Please lord make me this smart

[@TexasLeverGunner]

Randy, this is a good method, but with modern technology I don't know how much it applies anymore. Alpha Munitions brass with their "OCD Case head Technology" only moves about .0003 at roughly SAAMI max pressure. There needs to be a better way in 2024 for the average consumer to measure pressure outside of software like GRT or QL. QL is extremely anti-user friendly.

[@thomaspancoast275]

Every chamber is a little different so pressure is not that important. You have to mic the brass you are 100% right.

[@AP-ow5vu]

Thanks Randy, do you think it would work to take a file to the sides of a cheap 0.0001 micrometer to shape it into a thin blade rather than buy an expensive flat blade or ball micrometer?

[@TheRealGunsmith]

No. Buy the .0001 blade mic. Thank you and God Bless!

[@rotasaustralis]

There's no doubt that measuring case head expansion is a very poor indicator of pressure signs. This kind of information should not be propounded within reloading circles as it is inappropriate & verifiably false. There has been a number of studies conducted with the focus on the correlation factor of case head expansion vs pressure &, the correlation has been determined to be so poor that it is statistically no better than guessing at pressures ranges of + & - 20Kpsi of max pressure. In plain language, .00005" case head expansion has been measured as low as 20KPSi below max cartridge pressure & as high as 20KPSi above max cartridge pressure. These tests were conducted while measuring actual chamber pressure so as to consolidate a statistically robust correlation between case head expansion & known measured chamber pressure. Further more, neither SAAMI or CIP mention case head expansion as a reliable method for determination of a max pressure situation. Measuring case expansion to determine signs of overpressure or, no overpressure is reckless advise & should not be recommended.

[@newmexicosixshooter1994]

Jeeeezzz…Thousandths is 3 spaces not 4. Tenths, hundreds and thousands… .005 . 4 spaces is ten thousands.

[@406life]

Last time I checked 1/2 a thousandt is .0005, exactly what Randy described

[@Jack-ur5or]

As always Randy is rite on point…again! Best wishes from western Wyoming!