Well, in a test that I ran last weekend it did. I figured that I would give the CHE theory a try. Working up a load for my 223AI, I had a couple of incremental loads that showed pressure signs (slight ejector marks on the casehead). Sure enough, the primer pockets were a little loose on the brass from those ten loads. Measured the caseheads and they were .0005 larger than before the 'warm' loads were fired.

Seems like a good tool to keep an eye on loads that there is not a lot of available data around to reference.

Which told you more, the 0.0005" casehead expansion or the loose primer pockets?

I recently pressure tested and CHE'd some .223/5.56 ammo with an Oehler M43 usign a 21" TC Contender barrel. Three different M193 lots of ammo were tested; LC82, LC91 and new white boc Winchester WCC07. The MAP for the LC82 was 60,500 psi(M43), velocity 3271 fps with no increase in CHE. The MAP for the LC91 was 56,200 psi(M43), velocity was 3230 fps with no increase in CHE. The MAP for the WCC07 was 65,700 psi(M43), velocity was 3351 fps with no increase in CHE. Remington 50 HP factory had a MAP of 52,900 psi(m43), velocity was 3280 with no increase in CHE.

So what does all that tell me? CHE many times doesn't become apparent until pressures are way over acceptable MAPs and probably are equal to or exceeding proof loads. Similar tests I have thus far conducted with 8 other cartridges of various caliber indicates the same; with modern brass cases CHE does not many times become evident until pressures are very high indeed.

I wouldn't be the least surprised if kelbro's loads were indeed "warm".

Larry Gibson

Perhaps an interesting test would be to use 5 different brands of brass in a transducer equipped barrel. Slowly increment the loads up until the primer pockets expand. I am sure the variation would be astounding.

BTW Larry,
Your data dumps cold water all over the "predicting pressure with a chronograph" thread that was recently posted on this forum.

quote:

Originally posted by Ol` Joe:
Which told you more, the 0.0005" casehead expansion or the loose primer pockets?

I think that the two confirmed each other. CHE=Loose primer pockets/Loose primer pockets=CHE

quote:

Originally posted by Larry Gibson:
I recently pressure tested and CHE'd some .223/5.56 ammo with an Oehler M43 usign a 21" TC Contender barrel. Three different M193 lots of ammo were tested; LC82, LC91 and new white boc Winchester WCC07. The MAP for the LC82 was 60,500 psi(M43), velocity 3271 fps with no increase in CHE. The MAP for the LC91 was 56,200 psi(M43), velocity was 3230 fps with no increase in CHE. The MAP for the WCC07 was 65,700 psi(M43), velocity was 3351 fps with no increase in CHE. Remington 50 HP factory had a MAP of 52,900 psi(m43), velocity was 3280 with no increase in CHE.

So what does all that tell me? CHE many times doesn't become apparent until pressures are way over acceptable MAPs and probably are equal to or exceeding proof loads. Similar tests I have thus far conducted with 8 other cartridges of various caliber indicates the same; with modern brass cases CHE does not many times become evident until pressures are very high indeed.

I wouldn't be the least surprised if kelbro's loads were indeed "warm".

Larry Gibson

Validates my thinking that the typical accepted indicators can't always be counted on. I believe that the case design of the 223AI masks some of the signs of overpressure that we have become accustomed to seeing. And, with wildcats, max recommended velocities for each possible bullet weight are not always available.

It's a tool that I used when others were not available. Maybe not the best tool but it did show me something before my action separated. I was lucky that CHE paralleled loose primer pockets and slight ejector marks. That's not always the case. I do know better than to take three signs and not pay attention

quote:

Originally posted by SR4759:
Perhaps an interesting test would be to use 5 different brands of brass in a transducer equipped barrel. Slowly increment the loads up until the primer pockets expand. I am sure the variation would be astounding.

Indeed! This was WCC99 mil brass. Pretty tough stuff. The load must have been pretty warm to expand those pockets. That's why I didn't try it in Federal or Speer brass

quote:

Originally posted by kelbro:
.. I had a couple of incremental loads that showed pressure signs (slight ejector marks on the casehead). Sure enough, the primer pockets were a little loose on the brass from those ten loads. Measured the caseheads and they were .0005 larger than before the 'warm' loads were fired.

Hey Kelbro, Good for you. Did you get Ejector Marks anywhere from 0.0001"<->0.0004" CHE?

quote:

Seems like a good tool to keep an eye on loads that there is not a lot of available data around to reference.

Completely agree. I'd be inclined to say it is the very Best Tool available for a Wildcatter. Reason being is that a 0.0001" capable Micrometer has none of the typical problems associated with the HSGSs that, I believe, have been discussed a good bit in the past. And it provides that excellent data for about $25<->$30.

How was the accuracy?

quote:

CHE. Does it really tell you anything important?

Yes. It does to me. I use it when I have an interest in reloading to max and testing my brass to see if it's as good as another lot.

quote:

BTW Larry,
Your data dumps cold water all over the "predicting pressure with a chronograph" thread that was recently posted on this forum.

Not necessarily.
The idea behind the use of a crono is to compare the velocity of a specific set of components in a test barrel to the same set of components in your rifle.
This data of Larrys was showing the difference in velocity and pressure of various loads with different unknow types of case, powder, primers, and bullets. Not the same type of data nor can they be compared the same way.

and no I`m going any farther with ths.........

quote:

Originally posted by Hot Core:

quote:

Originally posted by kelbro:
.. I had a couple of incremental loads that showed pressure signs (slight ejector marks on the casehead). Sure enough, the primer pockets were a little loose on the brass from those ten loads. Measured the caseheads and they were .0005 larger than before the 'warm' loads were fired.

Hey Kelbro, Good for you. Did you get Ejector Marks anywhere from 0.0001"<->0.0004" CHE?

No other visible signs. The Rem 7.5 primers still had a little radius on them even on the cases that were .0005. Had I been only looking at primers, I might have continued.

quote:

Seems like a good tool to keep an eye on loads that there is not a lot of available data around to reference.

Completely agree. I'd be inclined to say it is the very Best Tool available for a Wildcatter. Reason being is that a 0.0001" capable Micrometer has none of the typical problems associated with the HSGSs that, I believe, have been discussed a good bit in the past. And it provides that excellent data for about $25<->$30.

How was the accuracy?

The load just under the '.0005 load' (about .2gr less powder) was the best. Under .25 for 5 shots at 100 yds. Just a hint of an extractor mark on two rounds. It was right at 100° and I won't be doing much hunting at over 100° so I think that I found my max. Now I need to drag the chrono out and see how fast she's going for a reference. Those JLK bullets are impressive!

quote:

and no I`m going any farther with ths.........

too late now...

A while back I had a thread going on some PMP 303 Brit cases that showed no expansion at all (PRE = zero) while the primer showed a healthy pressure. These cases turned out to be thicker than 'normal'. In this case the primer could be said to be a more reliable pressure indicator.

quote:

Originally posted by 303Guy:
...In this case the primer could be said to be a more reliable pressure indicator.

Hey 303Guy, Since Factory Ammo is available for the 303Brit, I'd suggest "PRE" would have provided, and would still provide, the very BEST Pressure "Indications" possible for you.
----

Hey Ol' Joe, No need to since you summed up that pile of worthless, misleading data real well.
-----

Hey Kelbro, What is a JLK Bullet? Sounds like there isn't a whole lot of need for more Testing with that kind of grouping. Or perhaps I should say there wouldn't be for "me".

And what will you be Hunting with this fine outfit?

?

quote:

Claiming it invalid....... now that it pitiful !

If it is really valid why do the real means of measuring pressure need to exist.
As you said the micrometer and the chronograph are nothing but inferences.

If I give you unknown ammunition and have you chronograph it you may not have a clue about the peak pressure it produces.
Velocity is not just about maximum pressure but is about average pressure and the total area under the time pressure curve.

quote:

Originally posted by Hot Core:

Hey Kelbro, What is a JLK Bullet? Sounds like there isn't a whole lot of need for more Testing with that kind of grouping. Or perhaps I should say there wouldn't be for "me".

And what will you be Hunting with this fine outfit?

JLK bullets is a California outfit that makes some nice J4 bullets for not too much scratch. They took over Swampworks and use his tooling. http://www.swampworks.com/jlk/

They shoot every bit as well as Bergers.


I will primarily use these for 200yd and better coyotes.

My gunsmith (who has been around the block a few times) told me over 30 years ago that the small cases like 222, 223, etc., DO NOT reliably show pressure signs like larger cases ie. 257 Rob., 270, etc.
Just for what it is worth, just last summer, I was messing around with some 270 Win. cases in WW brand. These particular cases had been re-loaded well over 20 times and only partial-resized everytime. I was loading at least 2 grains over any book. After about 10-15 reloadings, I noticed the primer pockets were getting loose on a few of the cases. I could push the primers in over 3/4s of the way in by hand and finish them off with slight tap of a mallet. I would them press them with again in press. I continued to fire them. I did not have a single one blow-out. I would not try this with Remington brass, which is much softer. Oh and yes the CHE was .0005 larger. I believe if you continually reload a case and only partial resize, the brass will eventually keep on expanding until it can't anymore. I eventually threw the brass away after about 30 reloadings - I figured I got my money worth out of it.

CHE is just a "tool" and nothing more. To some -- especially one or 2 on this board -- it is gospel, but those folks are kidding themselves if they think it's the final word in pressure indications.

Other facets must be taken into account. Reloading is filled with variables, and unless you give careful consideration to them all, your results may not be what you had hoped for.

quote:

Seems like a good tool to keep an eye on loads that there is not a lot of available data around to reference.

YES!

I don't always stop where the book makers stopped (I usually do) but, in my OPINION, all of those three are certain signs of significant over-pressure. I have always backed off when any one of: sticky extraction, bolt head marks, loose/smoked primer pockets or CHE appeared.

Even with no other signs but loose primer pockets after four or five cycles, I back off. Pushing the actual pressure limits gains precious little down range, and that little at the expense of safety, case life and firearm damage.

Agree with most all of you. None of the indicators are 100% accurate. The more tools that you have and use, the better chance that you have of not blowing anything up.

quote:

Originally posted by kelbro:
...JLK bullets is a California outfit that makes some nice J4 bullets for not too much scratch. They took over Swampworks and use his tooling. http://www.swampworks.com/jlk/

They shoot every bit as well as Bergers. ...

Hey Kelbro, Thank you. I'll check them out.

quote:

Whammed in by "my hero" alf:
I personally choose the chrono because ... it is in fact internal ballisitcs.

Great discussion Gentlemen!

I don't yet own a micrometer so checking CHE or PRE is not an option for me now. Do you here believe that relying on visual and tactile pressure indicators (flat primers, sticky bolt, and yes....I have a chrono so velocity for selected loads exceeding book max's) will suffice?

?

Don't let me stop you. Y'all have fun!

quote:

Originally posted by rcamuglia:
...I don't yet own a micrometer so checking CHE or PRE is not an option for me now.

Hey RC, For about $25-$30 you can correct that problem and be able to take "PRE" on any Cartridge you have.

A set of Thin Blade micrometers is normally kind of expensive, but I got mine from a Pawn Shop for $25. You need the Thin Blades to measure "CHE" on some Cases, because the Rim is often so wide that it prevents you from getting to the proper measurement spot with typical Round Anvils. You can measure CHE across the Belt on your Belted Cases with regular Round Anvils. The Thin Blades also allow you to measure Groove Expansion(like tnekkcc does) and of course any Expansion at all in the Groove is loosening the Primer Pocket.

quote:

Do you here believe that relying on visual and tactile pressure indicators (flat primers, sticky bolt, and yes....I have a chrono so velocity for selected loads exceeding book max's) will suffice?

Multitudes of folks have done exactly like that for a long time and do just fine. Having watched that same stuff for over 5-decades, I'd say it can mislead you until the Bolt does get Sticky - on regular Factory Cartridges. Few folks seem to back-off prior to the Sticky Bolt Lift, unless they are using CHE & PRE.

If you use an "Improved Cartridge"(non-factory), then you may not get a Sticky Bolt Lift until you are REALLY beyond where you want to be. Only measuring "CHE"(as Kelbro is doing) and watching the Primer Pocket Expansion works to keep you totally SAFE with Improved Cartridges. 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.

If you get a few of your buddies together that all have a rifle chambered for the same Cartridge, run the exact same ammo through each one(it can be Factory so it fits in all of them) and Chronograph the results, you will quickly see why "Velocity" doesn't tell you a whole lot of useful information. Some of the barrels will be faster and some slower, so looking at Velocity and making a Load decision based on it, is misleading at best and potentially dangerous at worst.

I encourage folks to learn about CHE & PRE because the Methods are easy to learn, inexpensive and will keep you Safe when properly used. That said, a lot of folks never measure CHE & PRE and get along fine.

Never under ANY circumstances use anyone elses Reloads in your firearms. Perhaps that person "might have" the same level of Reloading knowledge as alf and warrior - Pitiful!

quote:

CHE. Does it really tell you anything important?

It could. But only once. That is to say, only new, never fired brass qualifies for CHE. So that disqualifies any wildcat brass that needed fireforming to chamber. At least that's what Handloader Mag editor Dave Scovill said about CHE testing his 338 Hawk\Scovill wildcat. He ended up jumping through lots of hoops to get virgin brass that would give meaningful CHE data.

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?

You'll look far and wide to find one. And when you do it won't be 25 bucks. So that old 'CHE|PRE can be done on the cheap' is pure horse hockey! A lie told often enough eventually becomes believable.

I'm putting on my waders in preparation for Hotcore's rebuttal.

quote:

If you get a few of your buddies together that all have a rifle chambered for the same Cartridge, run the exact same ammo through each one(it can be Factory so it fits in all of them) and Chronograph the results, you will quickly see why "Velocity" doesn't tell you a whole lot of useful information. Some of the barrels will be faster and some slower, so looking at Velocity and making a Load decision based on it, is misleading at best and potentially dangerous at worst.

quote:

Just opinion HC but I don`t believe in "fast and slow" barrels. My personal take is there are variations in the bores and chambers that affect pressures and a "faster" barrel is likely producing higher pressure at some point then the "slower" one.
A rough throat can cause a faster rise due to friction on the bullet or and difference in throat lgt (freebore) as examples.

Edited to add; the higher psi producing bbl is the likely the one with the higher velocies.

quote:

Originally posted by rcamuglia:
Great discussion Gentlemen!

I don't yet own a micrometer so checking CHE or PRE is not an option for me now. Do you here believe that relying on visual and tactile pressure indicators (flat primers, sticky bolt, and yes....I have a chrono so velocity for selected loads exceeding book max's) will suffice?

It will suffice along with data referenced from several loading manuals. This information has "sufficed" for years and still will for those who want to safely load ammo within specified range of velocity and accuracy. However for those who wish to push the envelope nothing short of blown primer pockets seemingly will "suffice". By the time you get to expanded or blown primer pockets you are well into or beyond "proof" load pressures.

Many years ago I was "into" pushing the envelope but have since learned better, the hard way. That's why I now, when working up a load, reference loads from several manuals, watch for the usual pressure signs, chronograph the loads watching for consistency, expected velocity increase between loads, expected velocity levels for the load/cartridge/barrel length and now I also measure the pressure via an Oehler M43. The Oehler M43 certainly gives me an extra level of knowledge but isn't necessary if the others are adhered to as they are indeed "sufficient".

Larry Gibson

Brass is the rate limiting component in high-performance reloading - I think we would all agree on that. Thus, we have no choice but to work within the PSI limitations of the brass case. If we go beyond those limits, then we risk a blown primer with gas back into our eyes, a ruined case, and/or a frozen bolt - just as the trophy of a lifetime walks into the timber and you can't get a second shot. Thus, you want to stay within the PSI limits of the brass. A well-made bolt-action rifle can withstand PSIs in the 150,000 PSI and beyond range. Brass will begin to show evidence of "excessive flow" beginning around 65,000 PSI with a blown primer consistently occurring with a new case at around 80,000 PSI. Brass is an imperfectly elastic metal, and primer pockets begin to loosen quickly as you multiply shoot the same case at 65,000 PSI and beyond - Lapua claims their brass is made to "withstand" PSIs of 67,000 PSI. But, even their pockets will loosen quickly at these PSIs. Important to note is that, even with very precise reloading, there will always be variance in PSI (e.g., suppose your aiming for 65,000 PSI as an average, but you know some of your rounds will fire at 67,000 or 68,000 PSI while others go at 62,000 to 63,000 PSI - and that if you are VERY PRECISE in "cloning" you loads). If you're a beginner or a sloppy reloader, don't load at 65,000 PSI. I only use custom made, modern bolt-action rifles with brench rest-rifle quality after-market barrels and trued-up actions. I hand weigh each powder charge and double-check. I use only match primers and primium bullets - no seconds. Moroever, as I shoot, I examine each case for pressure signs and chronograph each round, recording all individuals velocities. Using this approach one becomes pretty good at reading pressure signs as they develop, thus avoiding a blown primer.

People keep talking about the importance of metal fatique, which I don't deny. But, with a modern bolt-action rifle it would take thousands of rounds fired at less than 70,000 PSI before metal fatique would become an issue. By then and at these PSIs, your barrel will be losing accuracy and throat erosion would likely cause significant drop in PSI and velocity. Moreover, there is no need to fire that many high PSI rounds. Once you have your hunting load worked up set them aside only to be used during hunting season, you'll need to fire only 5-10 rounds per year. If you want to shoot thousands of rounds at the range, back off into the 40,000 PSI range - targets don't need much killing and accuracy is often easier to find at lower PSIs.

I don't use CHE/PRE, but I bet - as Hot Core reports - it works. I just don't think it's worth the trouble. As CHE/PRE limits are exceeded, primer pockets get loose quickly. One can "feel" primer pocket loosening with a hand priming tool. Sinclair offers a nice hand-priming tool at a reasonable price. The Lyman reloading manual recommends at least 3 case reloadings before "significant" pocket loosening as safe. I've used this approach for 20 years without any problems.

Regards, AIU

What do the following runs tell you CHE/PRE guys?
Chamber A, 10 rounds factory ammo, CHE-PRE (round anvil, placed ahead of the rim) was within .0001 and velocity was 3000fps
Chamber B, 10 rounds fired, expansion was .0020-.0035 larger (egg shaped) than chamber A and the velocity was 2750

Again with chamber A, 10 rounds fired, expansion the same as before, velocity was 3100
Finally, and again with chamber A, 10 rounds fired, expansion the same and velocity was 2875.

Note: all 40 rounds came out of 2 boxes of factory ammo, same brand, weight and lot number. The first 2 I mentioned were with the ammo at 65^F, the third the ammo was left sitting on the dash for 45 minutes (and was fired at that temp), and the 4th run was with ammo that had sat in the a freezer for an hour (and was fired at that temp)

Not really enough data to really tell you anything more than anecdotal info.

Chamber A behavior sounds normal. Higher temp, higher velocity. Lower temp, lower velocity. You didn't mention cleaning so you could also have some copper buildup working against the consistency of the later rounds.

Chamber B. Don't what you can gather from the data that you posted except the egg-shaped chamber.

Chamber A is a tight chamber, chamber B is loose and irregular. I'd replace chamber B. Shoot the same load in both with neck-sized cases only from each chamber, then measure.

?

quote:

Originally posted by kelbro:
Not really enough data to really tell you anything more than anecdotal info.

Chamber A behavior sounds normal. Higher temp, higher velocity. Lower temp, lower velocity. You didn't mention cleaning so you could also have some copper buildup working against the consistency of the later rounds.

Chamber B. Don't what you can gather from the data that you posted except the egg-shaped chamber.

Barrel was cleaned after every 10-20 shots
Higher temp, higher velocity equals HIGHER PRESSURE but we got the SAME expansion
Lower temp, lower velocity equals LOWER PRESSURE but we got the SAME expansion
With B, Lower velocity, lower pressure (oversize throat) MUCH GREATER expansion.
Tells me that "measuring cases" is a waste of perfectly good time.

AIU
Custom match chamber vs factory chamber (both 30-06 BTW). Chamber A produces what "the books" say their test barrels got

Alf
Both barrels had 3 sets of Whetstone bridges attached (chamber, mid point and muzzle), and A repeated the runs with 8 different hand loads also (4 powders @ book max, 2 primers) all done in new brass of the same make as the above tests.
What I'm going on right now is my memory of the raw chrono. and measurement data, I don't have a copy (yet) of the completed report.

quote:

Originally posted by Ackley Improved User:
Brass is the rate limiting component in high-performance reloading - I think we would all agree on that. Thus, we have no choice but to work within the PSI limitations of the brass case. If we go beyond those limits, then we risk a blown primer with gas back into our eyes, a ruined case, and/or a frozen bolt - just as the trophy of a lifetime walks into the timber and you can't get a second shot. Thus, you want to stay within the PSI limits of the brass. A well-made bolt-action rifle can withstand PSIs in the 150,000 PSI and beyond range. Brass will begin to show evidence of "excessive flow" beginning around 65,000 PSI with a blown primer consistently occurring with a new case at around 80,000 PSI. Brass is an imperfectly elastic metal, and primer pockets begin to loosen quickly as you multiply shoot the same case at 65,000 PSI and beyond - Lapua claims their brass is made to "withstand" PSIs of 67,000 PSI. But, even their pockets will loosen quickly at these PSIs. Important to note is that, even with very precise reloading, there will always be variance in PSI (e.g., suppose your aiming for 65,000 PSI as an average, but you know some of your rounds will fire at 67,000 or 68,000 PSI while others go at 62,000 to 63,000 PSI - and that if you are VERY PRECISE in "cloning" you loads). If you're a beginner or a sloppy reloader, don't load at 65,000 PSI. I only use custom made, modern bolt-action rifles with brench rest-rifle quality after-market barrels and trued-up actions. I hand weigh each powder charge and double-check. I use only match primers and primium bullets - no seconds. Moroever, as I shoot, I examine each case for pressure signs and chronograph each round, recording all individuals velocities. Using this approach one becomes pretty good at reading pressure signs as they develop, thus avoiding a blown primer.

People keep talking about the importance of metal fatique, which I don't deny. But, with a modern bolt-action rifle it would take thousands of rounds fired at less than 70,000 PSI before metal fatique would become an issue. By then and at these PSIs, your barrel will be losing accuracy and throat erosion would likely cause significant drop in PSI and velocity. Moreover, there is no need to fire that many high PSI rounds. Once you have your hunting load worked up set them aside only to be used during hunting season, you'll need to fire only 5-10 rounds per year. If you want to shoot thousands of rounds at the range, back off into the 40,000 PSI range - targets don't need much killing and accuracy is often easier to find at lower PSIs.

I am with you on the numbers for a .47" large Boxer primer rimless case, like a 30-06.
But the .376" small Boxer primer rimless case, like a .223 can take more, per my experiments.

tnekkcc, how much more can the .223 take. My obsevations are with '06 and 300 Win Mag cases. Regards, AIU

quote:

I don't use CHE/PRE, but I bet - as Hot Core reports - it works. I just don't think it's worth the trouble.

Warrior

Warrior says he agrees with Alf and Hot core is wrong.

quote:

Hot Core = HC = Holistically Confused

Warrior says he agrees with Alf and Hot Core is right.

quote:

I don't use CHE/PRE, but I bet - as Hot Core reports - it works.

Alf, this guy is giving you a bad name, you gotta shake him somehow.