quote:

Originally posted by Tailgunner:
What do the following runs tell you CHE/PRE guys?

Hey Tailgunner, I'd suggest the reason you are having trouble with CHE/PRE is because you have somehow gotten how to take the measurements just a bit confused. That happens a lot with all the Bad Info floating around, so don't get concerned, do as it says in the Link below and you will do fine. CHE and PRE are "separate" measurements and are done differently.

quote:

Chamber A, 10 rounds factory ammo, CHE-PRE (round anvil, placed ahead of the rim) was within .0001 and velocity was 3000fps

The number 0.0001 appears to be a CHE measurement of 0.0001". Since the Case was previously "unfired", the CHE measurement is meaningless. The Cases need to be "Once-Fired" and the Velocity has no bearing on the issue. Also, the CHE needs to be measured in the exact same spot before firing and after firing. Ten Cases are more than enough for Averaging CHE.

And to answer the question, if the measurement was taken while following the Instructions in How to measure CHE & PRE, then your 0.0001" CHE says the Load is Safe and the Primers will still be snug Seating. But, since they are new Factory Ammo, you can't use them for CHE measurements - unless you just want to practice.

quote:

Chamber B, 10 rounds fired, expansion was .0020-.0035 larger (egg shaped) than chamber A and the velocity was 2750

This appears to be PRE if the numbers indicate 0.0020"<->0.0035" and again the Velocity is meaningless to CHE & PRE.

From seeing that wide of a spread, it indicates to me that you have a great opportunity to lower the Variation with Reloads. With good Reloads, the Variation in PRE should be 0.0000"<->0.0004" for 3-5 shots.

Normally you "Average" all the PREs for 10-20 shots and use that PRE Average as your Safe MAX PRE. With that wide of a Variance, I'd be interested in what the Average PRE turned out to be.

The PRE for one barrel has noting to do at all with a separate barrel. You have to establish the Benchmark Standard PRE for each barrel separately as you did. And what is a Safe Max in one has nothing at all to do with the other one.

If that dosen't help you, you can send me a PM with your phone number and I'll call you.
-----

Hey Ol` Joe, I'm going to start a thread about Fast & Slow barrels so we can discuss it there.

Is there ANYONE on the Board that thinks warrior and alf have a clue???

You are wrong again, it may work for HC, but for most others it is too much trouble, and then please don't forget all the imponderables that Alf mentioned. For me it is out too.

Selective quoting is giving you a bad name, not me, and your shitty attitude with Alf on a subject matter that you have not contributed one iota. No one will give you a better explanation than Alf, and all you can say it is irrelevant. You have put nothing on the table, just playing your game. Many ballisticians hold the view that mass is favoured in our ballistic system, not just me and Alf. This is actually typical of spead-freaks that are in denial !!!

Warrior

Years ago when the Sendero first hit the market, a close friend and hunting bud, picked one up in 7mm magnum, and brought it to me to work up a load for use to use on feral hogs at long range. Typical to most every load I work up, I consulted just about every book available at the time for load data on several bullets which I felt offered the very best weights and BC's for our project.

Also since he and his Uncle had a very well stocked machine shop I burrowed their blade micrometer specifically for this project. I purchased new Winchester cases, had the barrel hand lapped to a very fine polish by a gunsmith friend of mine, and went about gathering up powders for the task at hand.

Setting up my chrono, I loaded and shot 10 rounds of factory ammo to get a standard reading on velocity using 160gr bullets. At the time of firing I also took readings on the case head, and ring of the case as well as neck and body dimensions. This as to ensure that I got everything covered as I worked up my loads.

Once I found a suitable powder that was giving similar velocities in the factory cases, and not exceeding the pre measured dimensions, I set about working with the new cases. I worked up to the same level of expansion by simply dumping powder from a Uniflow measure and shooting them into a 100yd target. At this point I was more concerned with the groups I was getting and the expansion. After hitting a nice groups with the same 10 factory cases which were not exceeding but were right at the same expansion, I chrono'ed them and found that they were way below what they should have been. Some 250ft plus slower, putting them in the same ranges as a .280 Remington. Shooting the 10 cases I purchased as bulk produced similar results with both measurements and velocity.

With this data in hand, I proceeded to ease the powder charge up on these same 10 cases. As I shot I measured them as well and not until after I had seen a 75 then 150 fps spike on my chrono, did I see any measurable differences in what they had been when I started on their first firing, to what they were after hitting the second spike in velocity. This now put them running a 162gr Hornady BTSP in the 3260fps range. Now granted the accuracy out to 300yd was awesome grouping right at 1", and I could get around 4 loads from them before the pockets started to loosen up. However this was at a temperature of around 50 degrees, and once it warmed up to 75, simply firing the round on the first load was the end of use for that case.

I have used both methods through some of my short 35 something years of loading. I have also simply loaded shot for groups and felt great about the loads with out using either. However, IF, I am looking to work something up in any particular caliber, I will trust the chrono over the mic every time. I felt that with the above described load, I proved to myself, (and that is all that really matters to me anyway,) that when the load is increasing steadily by 25 or so feet per second per charge change, then it jumps to 75 or higher, that this is the stopping point regardless of the resulting velocity or accuracy of the load, and I either back off to the next lowest best grouping load, or drop that idea and go on with other more suitable powders. In using this method with appropriate powders chosen from known data, I am generally within 200 or less fps of published data one side or the other. If the groups aren't coming around to what I like, I change powder and start over. If I try using a powder which is in the same characteristics as several others but not listed I can also use the same method to accurately look for the same signs.

Will measuring the case give accurate results, or will they mirror what I saw above with the Sendero? Well there lies the crutch of it all, both methods will screw you if you let them. They both take time to learn over a broad base of different case brands, powder types, and differing bore dimensions. Yes they are both revelent to producing an accurate load for a given set of components within the limits of a particular rifle at the time, and under the conditions at that time. However using one over the other is the same as picking one brand of rifle, car, or bullet over the other simply due to one own personal experiences with them.

It might be better for you, but your not the one who will be sitting behind my scope when the sear breaks, nor is one any more definitive in proving the "actual pressure" of any given caliber of cartridge over the other. Both leave a lot to chance, it up to the end user and interpreter to decide which is more accurate for their uses.

Bottom line it all boils down to one opinion over the other, and opinions are like a$$hole we all have one and most thing the others stink.

Hey Warrior,

quote:

You are wrong again

I cannot be wrong again because I have not been wrong before.

quote:

Many ballisticians hold the view that mass is favoured in our ballistic system, not just me and Alf.

Ah...Now you fancy yourself a ballistician. If that is so, the ballistic science is in dire trouble. What about Alf? I thought he is a doctor.

These ballisticians, who hold the view that mass is favoured in the ballistic sciences that are important to us as sport shooters and hunters, who are they?

"A man with one watch always knows the time. A man with two or more is never quite sure."

One thing that everyone does seem to agree on is that there is no single tool to determine max or near max pressure. I like posts like this that have a lot of different ideas for achieving the same results. The real goal is safety. Nobody gets blown up and all is good.

It would be pretty boring if it was all fixed and there was only one load for each rifle that consisted of one brand and weight of bullet, one primer, one type and weight of powder, and one brand, length and weight of brass.

Hot Core, why use PRE/CHE, if feeling for loose primer pockets is just as effective and much easier to do? Regards, AIU

AIU,

ASSCLOWN, when he was here, calculated that the Mauser case head [30-06 type] was good for 76kpsi and that the .223 case head was good for 86kpsi.

I find that there is almost no margin above 65kpsi [pressure estimates per quickload calculations] in the Mauser case head.

I have not done allot of testing on the 223 failure threshold, but it seems to be between 80kpsi and 92kpsi. I have done long term multi case tests at 66kpsi. The SAAMI registered max is 55kpsi.


---------------------------------------------

The logic error made by many is that the absolute pressure of a load matters.
In a strong fire arm, it does not matter.
Usually, the effect on the brass is all that matters.

Measuring pressure to predict the effect on the brass, instead of looking at the brass, is how Denton and Oehler get money from suckers.

tnekkcc, thanks for the comeback, but please clarify. Is ASSCLOWN saying that the 3006 case primer pocket will fail after one firing at 76 Kpsi and the .223 case at 86 Kpsi? Also, I'm not sure what you mean "no margin above 65 Kpsi" in the Mauser case head.

Finally, I sure agree that one needs to watch the effects of PSI on the brass, where the real and practical evidence of excessive PSI resides. IMO it's time to stop when one sees ejector port marks or dents and/or rapidly developing loose primer pockets - they tend to occur together. When these things happen, one is close to blowing a primer or exceeding the elastic recoil of brass, thus risking a frozen case in the chamber. If the elastic expansion of the chamber exceeds the elastic recoil of the brass, you'll have a frozen case and/or bolt to deal with. Any thoughts?

Regards, AIU

quote:

Originally posted by Ackley Improved User:
Hot Core, why use PRE/CHE, if feeling for loose primer pockets is just as effective and much easier to do? Regards, AIU

Hey AIU, You must have missed part of a post on the first page:

quote:

Whammed in by Hot Core:
...You can always load five at say 50.0gr of Powder, shoot them, and then go home, Resize/Decap and see if the Primer Pockets are looser. Then load five more at 50.25gr, shoot, go back home, etc. But that takes a bit more time than using the good-old, never-fail, totally repeatable, "CHE".

Some folks just load up a whole Series of shots and begin blasting away. Lets say they had 6 different Loads and the Primer Pocket Expansion began on Group #3, but they have no way of knowing it. So they have Loose Primer Pockets on #3, #4, #5 & #6. Depending on how much additional Powder they are adding and how large the case is, they may have ruined the Cases and subjected the rifle to Stress it didn't need. Probably not going to Ka-Boom it, but it didn't do it any good.

That is part of the answer, but it is perhaps best answered by saying, CHE & PRE allow you to "ease toward" a Safe MAX and know when to STOP before going too far. You eventually get to where you STOP before you get an Ejector Mark or a Sticky Bolt. Nor are Worthless Cases created due to loose Primer Pockets. Best of all, you do not exceed the Pressure Limits of the weakest Link in the Firing sequence that tnekkcc mentioned - the Case.

Once you get in the rhythm of measuring and recording the data, it goes pretty fast. And it allows for the barrel to cool a bit. Granted, it is not near as fast as not doing it.

I grew up using CHE & PRE, so I'm used to them. Having done this for a long time, I really do not see anything better. That said, plenty of folks get along fine without CHE & PRE.
-----

Hey Kelbro, Nice post above that I agree with.
-----

Wooooops, nearly forgot.The current number of folks who believe warrior and alf have a clue is - TaDaa - Zero!

Hot Core, thanks for the comeback. The issue becomes...what is going too far? For me, going too far is defined by loose primer pockets, which is a practical definition. Obviously, in the field I want the case to hold the primer and I don't want to be too high in PSI to cause a blown primer from anticipated variance, especially if I might encounter warm temperatures while hunting. I doubt I've ever put 100 high-performance, hot rounds through any of my rifles, and thus, I don't fear "metal fatigue."

I believe I've become quite good at reading increasing pressure signs at the range and I rarely totally ruin a case anymore, although on purpose I'll find where significant pocket loosening occurs. Cases are cheap, even negligible, relative to the overall cost of my hobby. If I go through a few cases to find my stopping point, I can afford it. I can usually find the loosening point after one trip to the range after firing a ladder sequence of incremental powder charge increases, while concomitantly chronographing each discharge. The clues are usually clear-cut - excessive velocity (as predicted by QL), ejector port impressions, and markedly flattened primers. Ejector marks, heavy bolt lift, and a black ring around the primer are strong signals to stop. If accuracy is less than MOA, the next trip to the range is to fine-tune the sightin. Then I'm ready to hunt.

Three more questions, if I may. At what PRE or CHE do you also observe "significant" loosening of the primer pocket? - "significant" = noticeable easier hand priming. Second, how does full sizing effect PRE or CHE? Finally, where do you measure PRE/CHE on belted magnum cases - at the belt?

Regards, AIU

quote:

Originally posted by Ackley Improved:
...I believe I've become quite good at reading increasing pressure signs at the range and I rarely totally ruin a case anymore, although on purpose I'll find where significant pocket loosening occurs. Cases are cheap, even negligible, relative to the overall cost of my hobby. If I go through a few cases to find my stopping point, I can afford it. I can usually find the loosening point after one trip to the range after firing a ladder sequence of incremental powder charge increases, while concomitantly chronographing each discharge. The clues are usually clear-cut - excessive velocity (as predicted by QL), ejector port impressions, and markedly flattened primers. Ejector marks, heavy bolt lift, and a black ring around the primer are strong signals to stop. If accuracy is less than MOA, the next trip to the range is to fine-tune the sightin. Then I'm ready to hunt.

Hey AIU, That Method obviously works well for you, and you have a good bit of first-hand experience to base your Judgment Calls on. A Beginner/Rookie can use CHE & PRE with regular Factory Chambered Cartridges and easily learn when the things you notice begin to occurr that they would have trouble detecting "early on" in the Firing Sequence. And as Kelbro, CHE provides an Early Warning when PRE is impracticle.

quote:

At what PRE or CHE do you also observe "significant" loosening of the primer pocket? - "significant" = noticeable easier hand priming.

All good questions. Once you "typically" get to 0.0005" CHE the Primers are loose enough that even a Beginner would notice them. It is not a "precise, exact number" and may be 0.0004". So, it is a Weasel-Word answer.

quote:

Second, how does full sizing effect PRE or CHE?

Either Full Length Resizing or Partial-Full Length Resizing is required for PRE while Developing Loads. The Pressure Ring needs to be Resized to see how much it Expands with each shot. If Neck Sizing is done, the Pressure Ring is not Resized and the PRE data is worthless.

Any type of Resizing is fine for CHE, because the Case Head is not resized and the results become cumulative. By that I mean if your Load only creates 0.0001" CHE, over time that will loosen the pocket.

However, and this is something the Rookies/Beginners might not understand, "in some situations", continued Firing with Moderate Loads tends to Work Harden the Case Head. So, you can reach a point where it requires more Pressure than normal to force the Case Head into the "Plastic State" and once again Expand. When you get to this point(after many firings) it takes a relatively Larger amount of the same Powder to enter the Plastic State. For example, if you had been tracking CHE previously and saw:
1. 70.0gr gave 0.0001" CHE
2. 70.5gr gave 0.0003" CHE
3. 71.0gr gave 0.0005" CHE

And you decided to shoot them at 68.8gr because there was a nice accurate Node at that spot. If you shoot them 6-10 times, the Case Heads will Harden a bit. Now you may get:
4. 72.0gr gave 0.0000"
5. 72.5gr gave 0.0000"
6. 73.0gr gave 0.0005"<->0.0009" CHE or more.

Or perhaps you decide you want to try a "different" Load and since those Cases have done so well for you, you decide to use them. The problem here is CHE will not begin moving when it should because of the Work Hardening. Plus, once you reach a point where it does move, the same "increment of change" has the potential to cause a quick CHE change as it did above. Lets say you decided to use a slightly Faster powder, same Bullet and same "old" Cases. You might see:
1. 65.5gr gave 0.0000" CHE
2. 66.0gr gave 0.0000" CHE
3. 66.5gr gave 0.0005"<->0.0009" CHE or more.

So, it is important to limit the number of times a "Specific Set of Cases" is used for Load Development to one event. Some of that is in the Link(with different wording), but this explaination is not. Reason being the Link is intended for people just beginning to use CHE & PRE, and there is no reason to clutter their mind with unnecessarily complex thoughts.

quote:

Finally, where do you measure PRE/CHE on belted magnum cases - at the belt?

This should be in the Link.

On Belted Cases, you measure CHE across the Belt and PRE at the Widest Diameter forward of the Belt. And if measuring Groove Expansion as tnekkcc does, it is always taken inside the Extraction Groove.

Clear your mind of previous notions on "How to" measure CHE & PRE. Then just follow what is written in the Link. Otherwise, your results will be worthless.

Best of luck to you.
-----

And still - The current number of folks who believe warrior and alf have a clue remains at - TaDaa - Zero!

Hot Core, thanks for your responses - I appreciate it. Regards, AIU

This was my latest harvest. This is a 330 AZ bull, one shot at 308 yds. with a 300 Win Mag, 180 Accubond, 83 grs. Re25, ~3300 fps. The gun is in the pic. It is a trued Rem 700, 26.5" Kreiger, Jewel trigger, MacMillan stock, Harris Bipod, Leupold scope. Regards, AIU


[/IMG]

Looks like a NM bull.........

R, he was shot within a few miles of the NM border in the Blue River Primitive Area. This is my second 330 bull from the area - funny how those "350" bulls become 330 bulls with a measuring tape - you know, the "shrinkage" phenomenon. AIU

quote:

Originally posted by Ackley Improved User:
This was my latest harvest. ...

Hey AIU, Sure looks like a Kill to me - and a fine one at that. Congratulations.

Here's another, a decent muley shot in New Mexico at 515 yds. The gun is a trued Rem700, Jewel trigger, Leupold scope, HS Precision stock, 26.5" Kreiger, Harris bipod. Caliber 30-06 AI, 165 Accubond, 69 grs. Norma MRP, ~3200 fps.He was good eating and running around in the wide open spaces with his buddies - hardly a tree within a mile. Regards, AIU

Hey AIU, Another fine Kill. You must have two freezers.

Say, ummm... just getting back to topic briefly.... about PRE & CHE, I have some fired cases that show healthy pressure on the primer but virtually zero PRE. CDE will be the same. These have turned out to be thicker and stronger cases than normal. What then?

Now then, back to the deer... Those look like fine specimens to me.

Hey 303Guy, If it was someone using a recently produced rifle, I'd "guess" the Pressure is still low and the Primers are pulling a clinton on that person.

However, I've read enough of your posts to know you do not follow what I consider "routine, typical, or normal" types of Reloading sequences. Dosen't mean you are doing ANYTHING wrong, just different than what I'm used to.

So, I'm reluctant to offer any "guesses" concerning what you are seeing, based on what you may have done differently than I'd expect. I'm also not familiar at all with the rifles you use, so once again, I'm reluctant to "guess" about them.

Perhaps one of the other folks will be able to offer some assistance.

quote:

Originally posted by onefunzr2:
...Sinclair International sells lots of components and tools to those nit-picky benchrest guys. They also sell lots of 'thingys' and gadgets to make handloading more precise. Look through their catalog or website and point out to me where they offer a .0001" capable thin blade micrometer. They don't. Neither do Graf's or Midway or other vendors who cater to us reloaders. I wonder why?

Hey Dave, I don't know.

quote:

Originally posted by Hot Core:

quote:

Originally posted by onefunzr2:
...Sinclair International sells lots of components and tools to those nit-picky benchrest guys. They also sell lots of 'thingys' and gadgets to make handloading more precise. Look through their catalog or website and point out to me where they offer a .0001" capable thin blade micrometer. They don't. Neither do Graf's or Midway or other vendors who cater to us reloaders. I wonder why?

Hey Dave, I don't know.

I don't know why...that's the best you can come up with? You can drone on, and on, and on, about how strain gauge systems and chronographs are useless crap, yet the mandatory tool for measuring CHE\PRE isn't offered for sale by any internet reloading business and all you can say is, "I don't know?"

Measurement of the web most often requires a micrometer with a blade anvil since the web on most cases is narrow enough that the barrel anvil of standard micrometers is too wide to make that measurement - the rim and the enlarged pressure ring get in the way. Yet MidwayUSA offers 4 different brands of ball micrometers for the measurement of case neck thickness and not a single blade mic. Care to venture a guess why? Perhaps nobody reads Waters and Hagel anymore? Perhaps the majority of handloaders dismiss the error-prone CHE measurement procedure as not worth their time? Cause if there was a market for a .0001" capable blade mic, Larry Potterfield would try to make a buck off it. Don't ya think? For cripes sake Hotcore, you're still living in the reloading dark ages. Do you still shout the praises of the slide rule, too? Aw crap, why do I even bother?

Hot Core, those were actually Berdan primed factory loads I was refering to. They were not fired in my gun but the primers were crimped and show no sign of having backed out. Just the normal, 303 Brit factory loading. I cut one open and discovered they were real thick walled. (The brass seemed pretty tough too). I have nearly a hundred of these same brand cases in boxer. Even the necks are thick! I'll be using these for paper patched boolit's - they are ideal because with paper patching, I don't resize the necks.

quote:

that's the best you can come up with?

Hey Dave, Actually I first posted something worthy of the attitude you are offering me. Then I decided not to aggrivate you any more than you currently happen to be, and erased it.

If I did not think you actually had worthwhile information that I see you occasionally post, I'd be handing you what you are handing me, as I normally do.

Some of your questions in various threads are superb challenges to an existing idea or Method. Causes a guy to have to think through what he is doing and see if it has a problem. Any good Method can withstand a strong challenge. The ones that can't need to be Modified.

I agree the Thin Blade Micrometers are very expensive. It has been a long time since I priced a new set of Mitutoyo Thin Blade Micrometers from Mrs. Gleaves at "Gleaves Co., Inc." (502) 969-1959. I don't even know if they are still in business. They ran $144<->$169 back in 1988. Might be a bit more today.

I got my Mitutoyo Thin Blade Micrometers long before that at a Pawn Shop for $25. They may be selling them for more than that today as well.

Chances are though, they are less than a M43 used to be even without the Laptop. And the Micrometers actually provide "useful" Pressure Information, which is Calibrated to a known Standard - when used properly.

Best of luck to you Dave.

Yet again, you fail to see my basic premise. Which is: your beloved CHE needs only one fundamental measuring tool, yet no supplier of reloading tools offers one. Hell, not even an inaccurate, cheap knock-off chinese copy of a Starret or Mitutoyo. If the commie chinese don't see a market for it, that in itself says a lot.

CHE might not be totally useless, but it's more trouble than it's worth. If you can find the precise measuring tool needed to use it. If?

CHE is dead, deader, deadest. Moribund. Caput. Defunct. A dead soldier. Rest in peace, CHE.

HC, the following would seem adequate - am I correct? A bit expensive, although once in a lifetime I assume. Regards, AIU

STARRETT 786P-1 65225
No. 786, 786M Series , Electronic Digital Blade Type Micrometers with Non-Rotating Spindle (with Output), 0-1" Range, .00005" Resolution
Transcat Order#: 786P-1
Model: STARRETT 786P-1 65225
Mfg Part#: 65225

Our Price: $856.00 USD
Availability: Usually ships within 1-3 weeks

quote:

Originally posted by Ackley Improved User:
HC, the following would seem adequate - am I correct? A bit expensive, although once in a lifetime I assume. Regards, AIU

STARRETT 786P-1 65225
No. 786, 786M Series , Electronic Digital Blade Type Micrometers with Non-Rotating Spindle (with Output), 0-1" Range, .00005" Resolution
Transcat Order#: 786P-1
Model: STARRETT 786P-1 65225
Mfg Part#: 65225

Our Price: $856.00 USD
Availability: Usually ships within 1-3 weeks

Hey AIU, NOOOOOOO!!!! WAAAAAAY too expensive!!!!! (I don't see a Hot Core Passing-Out Icon due to things being WAAAAAAY too expensive.)

No doubt those are excellent Micrometers, but you sure don't need anything, anywhere close to that cost. NOOOooooo!!!
-----

All you need is a Regular Rould Anvil 0.0001" capable Micrometer that is able to provide - a Repeatable Measurement to start with. Then you can find a Deal on the Thin Blade Micrometers as time passes.

"Electronic Digital" Models have an annoying Design issue which is refered to as "Shifting Reading Values" that can drive a regular user crazy, let alone someone using them for the first time. This is one time where "buying the Best" is not the thing to do.

Look in the other thread about Fast Barrels because I gave a bit more answer there. If you want to talk about it, send me a PM with your Phone Number and I'll call you. I've got Unlimited Everything on my cellphone, so it is no problem to discuss the issue.

Let's see if I've got this correct: we're measuring the pressure of a reloaded cartridge case that was fired just a few inches in front of your eyeballs, where the difference between acceptable MAX pressure and a possible catastrophic failure is .0001" of case head swelling? Somehow I don't think I'd go for the el-cheapo measuring device.

quote:

Originally posted by onefunzr2:
Let's see if I've got this correct:

Hey Dave, No, not totally correct.

quote:

we're measuring the pressure of a reloaded cartridge case that was fired just a few inches in front of your eyeballs,

Good so far.

quote:

where the difference between acceptable MAX pressure and a possible catastrophic failure is .0001" of case head swelling?

No, no one has said, claimed, suggested, hinted-at, or dreamed that at all. The difference between a CHE/PRE determined Safe MAX and one additional 0.0001" equates to a slight loosening of the Primer Pocket. More 0.000X" equals more Primer Pocket Expansion.

Granted there is a point where that if the Expansion is too large, then a Catastrophic Failure is a possibility. Our buddy tnekkcc would be able to expound on that subject quite well.

So, no need to "make-up" incorrect info about CHE/PRE, because they can withstand the challenge. Unless if however you are trying to prove "if a lie is told often enough, etc."

quote:

Somehow I don't think I'd go for the el-cheapo measuring device.

Nothing wrong with that, but there is no reason to waste money at 200x what will work fine.

I have a book by BOB HAGEL that goes into depth about case head expansion.
I have decided I can do without that last 100 fps.If fact,my current load for my 30-06 is a 150 gr cup and core bullet at 2700 fps.Plenty accurate and more than powerful enough for hunting in the big woods,but then,my hunting is almost always well under 100 yds.

HC, I’ll likely go with a thin-blade, digital micrometer of very good quality. I’m a “practical” person and believe in using high-quality equipment applied in straight-forward ways. (For me, spending money for first-rate equipment is “practical.” Besides, I’ve saved money in my lifetime by staying married to one woman.)

It seems that the most reproducible technique of measuring CHE would be to measure the inner groove diameter. The case extraction groove would help steady the micrometer and help insure measuring the identical spot, the latter spot marked with a sharpie or guided by a stamped mark on the base plate such as the “3” of 30-06, etc. Does this alternative technique work and make sense?

Next, I plan to run an increasing ladder of loads using my usual technique and correlate Case Groove Expansion (CGE) with primer pocket loosening. With this information, the next time out I’ll be able to get immediate feedback at the range, rather than wait to get home to decap and feel the pockets. Any thoughts?

HC, I believe these Mitutoyo's would work and likely worth the expense - that is, a once-in-a-lifetime purchase. I believe the digital would be easier to read, inspite of the digital drift you describe. Regards, AIU


Standard Blade Micrometers (MIT Series 122)

Non-Rotating Spindle

* For measurements of narrow grooves, key-ways, and other hard to reach dimensions.
* Blade dimensions - .030" wide x .250" long.
* Decimal equivalents marked on frame (1" models 122-125).
* Hammertone green frame finish on 2", 3" and 4" models.
* Quick zero adjustment on the sleeve.
* Appropriate standards supplied.
Order # Manufacturer Description Price
0122125 MITUTOYO 0-1" .0001" Grad. $234.91
0122126 MITUTOYO 1-2" .0001" Grad. $245.71
0122127 MITUTOYO 2-3" .0001" Grad. $258.31
0122128 MITUTOYO 3-4" .0001" Grad. $275.41

OR

Digimatic Blade Micrometers (MIT Series 422)

Non-Rotating Spindle


For SPC output, order connecting cable 937387 (1m) or 965013 (2m).
Replacement Battery: 541980 (1 pc.), 541980-10 (10 pcs./set).
Order # Manufacturer Description Price
0422311 MITUTOYO 0-1"/0-25.4mm .00005"/0.001mm Resolution $585.15
0422312 MITUTOYO 1-2"/25.4-50.8mm .00005"/0.001mm Resolution $626.90
0422313 MITUTOYO 2-3"/50.8-76.2mm .00005"/0.001mm Resolution $661.50
0422314 MITUTOYO 3-4"/76.2-101.6mm .00005"/0.001mm Resolution $691.00

quote:

Originally posted by Ackley Improved User:
HC, I’ll likely go with a thin-blade, digital micrometer of very good quality. I’m a “practical” person and believe in using high-quality equipment applied in straight-forward ways. (For me, spending money for first-rate equipment is “practical.” Besides, I’ve saved money in my lifetime by staying married to one woman.)

Hey AIU, Nothing wrong with that thinking.

quote:

It seems that the most reproducible technique of measuring CHE would be to measure the inner groove diameter. The case extraction groove would help steady the micrometer and help insure measuring the identical spot, the latter spot marked with a sharpie or guided by a stamped mark on the base plate such as the “3” of 30-06, etc. Does this alternative technique work and make sense?

Yes and it works great. That is the Method tnekkcc uses.

I also use a Stamped Case Head Marker. As long as you use the same thing all the time, you will do fine and avoid confusion. I normally use the Middle Letter in WIN, REM, or FED since they have a "straight line" within the Letter. Doesn't matter what you use though as long as you can remeasure it.

quote:

Next, I plan to run an increasing ladder of loads using my usual technique and correlate Case Groove Expansion (CGE) with primer pocket loosening. With this information, the next time out I’ll be able to get immediate feedback at the range, rather than wait to get home to decap and feel the pockets. Any thoughts?

Absolutely. There is some variation form Lot-to-Lot, but all that becomes self evident as you get used to doing the Measurements, recording them and comparing them to other Pressure Indicators.
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I'd strongly encourage you to locate a person with access to an "Electronic Digital Micrometer" and checking it out. I bought 4 or 5 to upgrade some Measurement Equipment at one place I worked and none of the Quality Technical Inspectors liked them. They all had years of experience with the old Solid Spindle style(like me) and just never got comfortable with them.

Dosen't mean you won't like them though, especially since the entire Method is new to you.

Best of luck with the new Micrometers.
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I seem to remember a thread, either earlier this year or last year about buying Micrometers. You might do a Find and locate it then contact some of the responders for their input. I seem to remember a lot of excellent input from people with plenty of first-hand experience. Huuummm,maybe it was on the GunSmith Board if you can't find it here. There would be a lot of folks there with plenty of first-hand Micrometer experience and might suggest a good Supplier too.

I hate with HC around to admit I used a mic at one time to guest-a-mate where I was pressure wise, but.....

When I did I used a reg spindle and anviled Mitotoyo digital mic of 0.00005" resolution/0.0001" accuracy.

I took a fine tooth file and touched the case rim at 180 degrees, just enought to ensure it was out of the way and I wasn`t touching it when I measured the very edge of the case head ahead of the extractor groove. These "flats" also helped keep me measuring the exact same spot each time I checked that case.

It saved buying special mics and trying to find ink spots that rubbed off the case.


BTW, I didn`t "invent" this idea I read it somewhere 30 yrs ago

quote:

and trying to find ink spots that rubbed off the case.

And don't measure on the ink spots!

Hey Ol` Joe, Years and years ago, I did that too. I'd forgotten about it until you mentioned it.

I always thought it would be nice to have a Drill that would open wide enough, and had a deep enough throat to insert the Case, spin it and remove just a bit of the Rim.

I seem to remember it was a pain in the clinton to do, without bumping into the beginning of the Case Head. Probably just trying to go too fast. I sure was glad when I found the Thin Blade Mics.

Hey Warrior,

quote:

it may work for HC, but for most others it is too much trouble, and then please don't forget all the imponderables that Alf mentioned. For me it is out too.

I can see how CHE would be out for you. There is the difficulty in operating a mic and the record keeping that must connect to reality. I can see how that would be great obstacles for you. Now that you only have question marks to quote, I see you are in some difficulty.

Ag shame, we must not poke fun at you hey?

HC, I got my blade Mitutoyo micrometer (Digimatic), and it's a really fine piece of equipment. I don't see "measurement drift" yet. Over the next 6 mos or so I'll figure out at what CGE (case groove expansion) corresponds to "significantly" loosened primer pockets, and post them here. Regards, AIU

I think that followers of Che Guevara are clinging to a myth. He had a window installed in his office for viewing the many executions without trial that he ordered. Yet the liberals that run Wikipedia will ban anyone who "vandalizes" the web site with detractions.

How can people be so opinionated about Che, and be so wrong?

quote:

Originally posted by Ackley Improved User:
HC, I got my blade Mitutoyo micrometer (Digimatic), and it's a really fine piece of equipment. I don't see "measurement drift" yet. Over the next 6 mos or so I'll figure out at what CGE (case groove expansion) corresponds to "significantly" loosened primer pockets, and post them here. Regards, AIU

Hey AIU, Good for you. Depending on how much you shoot, it might not take 6 months. But I look forward to what you get.

When you change "Lots" of Cases, the potential is there for the CaseHead to begin showing GE & CHE at a different Powder Level. But, when they do Increase, it is typically beginning to loosen the Primer Pocket.

No totally worthless HSGS has that ability. And of course knowing what the Primer Pocket is doing indicates where the real MAX is located for those Cases.

Glad to hear you are ot having the Drift Issue. If you have some Cases that have been fired between 1-5 times and if you want to share some readings, toss them in.