[scythefwd]

I have a manual, modern reloading rev.2, that shows pressure as well as velocities for max loads. When looking at the .300 win mag loads, many of the MAX never load above this amount loads were actually below SAAMI max pressures by almost 4k in some instances. Same with the .308 load data, most of the loads were 2-3k lower than the max SAAMI pressures. Why is that?

If the max SAAMI pressure for .308 win is 62k psi, why only give load data that goes up to 59 psi (some max loads were as low as 55k psi)? Why not give full max loads and put a waring that you might blow up a gun that isn't in top condition on them instead? You would bet that the manufacturers make their guns to handle the max pressure for the caliber, why can't I find load data that will let me do that?

[ljnowell]

Lawyers, courts, judges, and a screwed up tort system in this country.

[rondog]

Yep, the CYA effect. Don't give people information they can hurt themselves with, and sue you over.

[Friendly, Don't Fire!]

You asked why not give a warning that someone may blow up a gun if using the maximum loads in a Reloading Manual that would have higher maximum charges.

The short answer is that most people do not read the "Caution"-"Warning" and any other such labels.

A lot of people see a MAXIMUM charge listed as that charge which they want to load - they figure the book doesn't lie, the gun is new, so it should be STRONG, and this is what some factory loads that are real "BARN-BURNERS" must use. So they go with it.

I know many people who do not "WORK-UP" a load, looking for signs of excessive pressure, i.e., flattened primers, hard extraction, flow of primer around firing pin, etc.

There are so many variables that need to be considered, including, but not limited to:

Lots of Powder vary - probably not much, but they do vary.


All scales are not necessarily calibrated to actual weights throughout the range of the scale. Any scale that has been calibrated at the factory may no longer be calibrated after shipment - if any parts on the scale have been changed at all, due to rough handling during shipment.


Just the difference in brass thickness alone from new brass vs. brass that has been loaded a number of times would be considerable thus varying pressures.


Differences in case volume between various brands of cases can result in changes of pressure.


Certain bullets may be seated tight up against the lands, thus causing a spikes in pressures.


Any deviation at all from the published loads could result in pressures so excessive that something in the gun has got to "give" - Possibly at the expense of a finger, hand, eyesight, etc.


Add up all the above variables, and add some that are not listed here, and consider "worst-case-scenarios" in that every variable is on the "HIGH" side of pressure and you are now working in pressure zones that could easily blow certain guns.

[ArchAngelCD]

Why are reloading manuals so conservative?
Short and simple, to limit liability...

[Remo-99]

If the max SAAMI pressure for .308 win is 62k psi, why only give load data that goes up to 59 psi (some max loads were as low as 55k psi)? Why not give full max loads and put a waring that you might blow up a gun that isn't in top condition on them instead?

Admin's will proberly ban my IP from this site, again. For saying such, but anyway.

Reloading data is mostly just a guide of what data those companies tested and considered safe in most firearms.
As they don't have control over which firearms their data is use in, for example a modern built boltaction in 308win is much stronger than say a 308win Re-chambered Lee Enfield SMLE that was designed over 100 years ago.

Going beyond max listed data is when you're on your own and have already been warned by powder/component companies against it and when you need to work up carefully and be fully aware of any signs that pressure limits have been reached, as most long time reloaders are aware of.

There's a few calibres that I load over max data on, and I wouldn't be doing that unless I had some faith in the strength of the action/rifle as a whole.
Brass life can be much shorter, as the action strength, on modern front locking boltactions, way exceeds the SAAMI standards for the cartridge.
So when reaching the limits of the brass it's well worth stopping there and reducing some.(a blown casehead can still have it's risks, even when the locking lugs are holding good and solid).

A modern front locking boltaction will fail somewhere in the vacinity of around 80,000psi to 120,000 psi(depending on make/design). The brass casing of the round will usually fail well before that.

i.e. Tight/hard extraction = case limits exceeded, swelled caseheads and primer pockets that barely hold a new primer in place = case limits exceeded, boltface imprints on the casehead = case limits exceeded,etc. It's the best indicators most reloaders have for excessive pressures as most don't have access to pressure testing devices. That's not the case with all actions where case limitions are above that safe pressure of those actions i.e. older/weaker designs/actions(rear locking bolt actions, lever actions, pump actions, etc.)

Unless your confident/well expeirenced enough to workup loads safely all I can say is stick the published maximums.

[Shrinkmd]

But not Hornady...

Their loads on several pistol rounds seem head and shoulders above what some other books say. Check out their 45 acp. Their recipe for 200 gr LSWC starts at 4.9 of Bullseye, and goes up to 6.3 or so. I made up a batch of 5.2, figuring this would be a medium starter round. Boom! Hotter than I was expecting. I do need to chrony that one, but compared to the 4.5 or 4.6 almost all the other manuals list, they are loading those up to 950 or so fps!

Then again, Lyman also had similar loads going up to 5.6 or 6.0. Unless there is something funny going on, I can't imagine shooting 45acp loads that hot.

But I do need the chrony to tell the tale.

[edSky]

maybe the books are written by people who actually do research, and define the parameters of their testing beforehand. perhaps they look at group size (something engineers like to call "repeatability"), in addition to pressure signs.

achieving maximum pressure may have it's applications. just like running a car for as long as possible at its maximum RPM. but engines are "engineered" to have an optimal performance range, and while they may spin really fast, their torque may drop off (and systems like cooling and lubrication may start to fail). it may be great for a 1/4 mile strip, but not so good for a 24 hour race.

do you want to set a record, or do you enjoy shooting? to each his own. it really depends on what you are after.

[Walkalong]

To help keep you from blowing your a** up. You should be thankful.

[ranger335v]

"...loads were actually below SAAMI max pressures by almost 4k in some instances."

Well, fact is, loading isn't all that precise. Pressure variations occur, the pressures we see in a book are AVERAGES, meaning they do have excursions somewhat higher than what is listed. The only way to actually know the pressire limits of any firearm is to move charges up slowly until it blows apart; then back off .2 grain. ?? Or use book max.

If anyone wants to go higher than some overly conservative book max there is nothing or no one to stop them but please don't test overloaded ammo on a crowded range.

[griz]

It's more than just liability. If you load a batch of any load the individual rounds will vary by several thousand PSI from each other. So they aren't just trying to keep the average pressure to a certain level, they are also looking at the maximum pressure possible with that combination. Some loads have higher spreads which forces more conservative loadings to keep the average acceptable.

It is true you can often exceed the max load in the book without damage, but the few times when you DO get damage make it a bad idea.

Edit: Well, that's what happens when I let work get in the way of posting, somebody just posted what I was getting ready to say.

[The Bushmaster]

And then there is the handgun that starts having high pressure signs even before reaching even Lyman's maximum load. Like my S&W mod 19 that starts having stuck cases (hard to extract) at just under maximum load...

I go with Walkalong on this...

[Deavis]

If you understand process variability then you can easily make a case for keeping the published pressure well beneath the maximum pressure. Just having the average pressure underneath the maximum pressure is NOT enough. There are so many factors here that could be pointed out that justify that decision but here are just a few.

1) The load manual has no control over lot-to-lot variation in powder characteristics
2) Test conditions dictated by the Z299 spec do NOT replicate your gun's chamber conditions at the moment of firing
3) Testing equipment is not all equal (barrel condition, crusher lot, calibration equipment, etc...) and will introduce variation into the data
4) You gun is not a test barrel (this should be very obvious)
5) small increases in powder charge can result in large changes in pressure (i.e. 3-sigma limits or maximum probably pressure predicted using statistical analysis)
6) No control whatsoever over your reloading techniques (seating depth, bullet choice, measuring methods, etc...)

I urge everyone to read the Z299 spec, it is enlightening to say the least if you've never read it. Before anyone brings up old manuals having stronger loads than today because we are all wimps, remember that measurement equipment has come a long way since Grandpa was shooting lead torpedos packed tightly with 2400.

[Cosmoline]

I haven't found the manuals to be excessively conservative. They *ARE* conservative but that's as it should be. Both because of the potential dangers due to load variations and because maxing out the load's potential is generally disadvantageous to accuracy. Even old Elmer Keith, who blew up a few Colts in his day, suggested backing off the published maximums to find the sweet spot load.

[Steve C]

I think most of you miss the point of the manuals and are assuming its Lawyers, a fear of litigation that dictate loads and that somehow maximum pressure is a holy grail that should be attained.

Manuals are not just a cook book to get a maximum pressure they are a guide to help you develop top notch accurate ammunition. If you read completely some manuals they will tell you that the maximum loads are given at a point where to increase beyond resulted in declining accuracy, erratic pressures and velocities not simply because a SAAMI maximum allowable pressure has been reached. In fact most manuals don't say anything about pressure other than their loads are below maximum pressure limits.

[Phone Guy]

What would be the advantage of loading to the maximum pressure anyway? If there was a load that was well within the pressure limits of whatever load you were shooting why go beyond that? I am just curious maybe someone could educate me?

[ants]

We have covered this subject two or three times in the last few years. It's probably hard to select the right search phrase, but you should be able to find those old threads with a little extra effort.

A lot of what we think is 'conservatism' is actually the engineering lab methodology for testing loads and assigning Maximum to the highest load. It's a matter of applying math to the data, and has nothing to do with lawyers and liability.

And a lot of what we think is 'conservatism' is exactly what Walkalong said.




That's why I'm very wary of buying used guns from you guys who think the warnings don't apply to you.

[nulfisin]

Because they want to keep you alive and not maimed. Seriously, they have an incentive to be as accurate as possible, without possibly knowing exactly what components and gun you are using. The more accurate they are, within the realms of safety, the more books they sell. What am I missing?

[kelbro]

Just read some of the posts here (and other loading forums) and you should understand.

Seems there is always a contingent that wants to push the envelope.

[Noveldoc]

Maximum pressure is way over rated. Especially if you are going for accuracy.

Tom

[rfwobbly]

And a lot of what we think is 'conservatism' is exactly what Walkalong said.

...and you know how dangerous those gun-slinging, Bible-totin', Republican-votin', conservative Alabamans are. :D

[Walkalong]

Yup....... :scrutiny: :D

[freakshow10mm]

Or they use the industry standard of maximum charge plus two SDs that is still under SAAMI MAP to get their max charge.

[jfh]

"...IIt's a matter of applying math to the data, and has nothing to do with lawyers and liability."

I absolutely agree, ants, as I do with freakshow10mm's comment in the post right above this one.

However, I'll bet it isn't the engineer that is making the final decision about what gets published. That decision, by some sort of upper-level manager (who may or may not be an engineer), is based on any number of considerations--the "facts" of engineering data, the legal advice about liability from the corporate lawyers, and yes, the sales department's advice about what is popular right now for marketing.

Jim H.

[scythefwd]

Guys, thanks for the answers. It is basically what I thought, but I still don't like it.
I don't intend to push the max limits, but I had to wonder why the hottest loads in my manual for the .300 win mag still fell under the "acceptable" pressures for the .308. I just didn't get the point of the larger case and pressure limit if you weren't actually going to use it.
Working up a load for accuracy is fine, but working up a load for certain characteristics like minimal arc, max retained energy at a x distance, while maintaining hunting accuracy could be reasons to push the limits of max pressures.

[ants]

Walkalong: Yup....... Anthony "Danger" Walkalong.
Danger his middle name!

[ants]

Perhaps there is a nuance not yet revealed. The standard deviation and the mathematics mentioned above IS the conservative approach built into the system.

Lawyers are too smart just to lower data. If someone suffers a loss and sues the publisher, ultimately the lawyer may be the liable party for telling his client to lower the data when the lawyer clearly has no expertise concerning the reloading of ammunition. Lawyers are too smart to put themselves in that position. [For instance, H110/W296 is actually dangerous when loaded too light. If the lawyer advises the lowering of H110 data without knowing the dangers, the lawyer may be found culpable of exposing danger to the unsuspecting public.]

Instead, the lawyer's advice is to place the client in the most defendable interposition (go look up that word). If the publisher follows industry standards and does what every other publisher does, he becomes defendable. That is the origin of the "Two Standard Deviation" rule. Two standard deviations has become the industry standard, and thus is automatically the Standard of Care metric needed by the lawyer to mount a defense. Look up the phrase Standard of Care and you understand more about how an industry defends itself in mediation, arbitration, and litigation. And how a plaintiff's lawyer will build a case against a member of industry who did not follow the Standard of Care.

Thus, industry "conservatism" is found in the Two Standard Deviation rule. They could use a one-standard-deviation principle, or a simple mean, or a fixed coefficient, or some other means and method for determing max load. But those would not be defendable under the Standard of Care.

[ir3e971]

I think another reason for being conservative in manuals is probably more general purpose. The manuals are written for a broad audience with a wide variety of experience levels and whose equipment will have varying levels of precision.

People on this board use everything from Lee loaders, dippers, to progressive machines, and precision scales that cost hundreds of dollars. Quality of firearms used with these loads will also vary from poor to outstanding.

From a responsibility aspect this necessitates being more conservative.

The purpose of the manual is to give all of these audiences loads that will perform successfully.

Those reloaders with more experience can continue to develop loads as they need to.
For my purposes, I have never needed to go beyond anything in the manuals I use. Others will have different desires or requirements.

[Walkalong]

Danger his middle name! I may swim in the edge of uncharted waters on the rare occasion, I just don't recommend it. ;)

The manuals are trying to keep us safe. There are so many variables out there. No two guns are exactly the same. No two power lots are exactly the same. No two scale operators are exactly the same. Some tests are done with real guns, & some use pressure barrels.

You may go over data ABC in gun A and be fine, but go over data XYZ in gun B and run into serious trouble.

There is data out there that can be exceeded a hair, and there is data out there where it would be dangerous to do so.

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

Universal proved a little "spiky" in 400 Corbon. In defense of Universal I did make too much of a jump with it. You know, like you aren't supposed to. Argh....

How much pressure? Too dang much. I do know how much velocity. 3 shots... ES = 3 and SD = 1. Avg FPS = :o

Close to blowing a primer. Sloppy firing pin/firing pin hole fit? Maybe, but still not good.

http://www.thehighroad.org/attachment.php?attachmentid=107829&stc=1&d=1256393654

[Ol` Joe]

Everyone that questions the manuals load limits, and why data varies from book to book, should get a copy of A-Squares "Any Shot You Want" http://www.midwayusa.com/viewProduct/?productNumber=524043 Then read the sections titled
"pressure Measurement and Interpretation"
"Effects of Change in Temprature"
"Effect of Change in Components"
"Difference from Lot to Lot"
This is all their report on what was found in their lab during the making of the manual and IMO is a "must read". Why other books don`t give similar info is anyones guess....
I will say you`ll have a whole new outlook on pressure and load variations once you are done.

[TEDDY]

in reading posts in this and other forums there are many who ask how high can I load X cal.they want screamers.and then they wonder why the gun blew.I started many yrs before you were born.and I had nothing to go by.my first loading was 8 mm WW1 mauser.30/06 brass driven into chamber with hammer.cut off with hacksaw.what length?who knows. filled with bulk shot gun and lead bullet cast in plaster of paris mold.using 30/40 krag R nose.had to hammer bolt open.the bullet melted and I had a shotgun.the lord protects fools and children.I found a lyman book and used that from then on.:mad:

[ants]

Great story, Teddy!!! I love it.

While still in high school, I tore the heads off a few 44 Rem Mag brass until I went back to the book and learned more about the difference between fast powder and slow powder. I only had one book available then: Shooter's Bible Reloading Guide. The info in it saved my bacon. I cast bullets in an old brass bullet mold from the 1800's (made for cap-n-ball revolver). I lubed the single groove with a 50/50 mix of parafin and motor oil because that's what Shooter's Bible recommended. Seems like a long, long time ago.

[ants]

'Ol Joe. Thanks for the reference. I'll go look it up.


Walkalong: Wow! Cup material flowed way back into the FP hole and sheared off right there!

[Maj Dad]

As a young hot-shot reloader, I used max load data not as a number to be approached cautiously, but as the upper limit in the range of acceptable loads. It resulted in my having to beat open the bolt on my custom Mauser 308 with a 2x4 because I was using military brass instead of commercial :eek: . It was one of the first "aha! s" of my reloading career, and has evolved into a true understanding of why each and every load manual, and experienced reloader, will state over and over: WORK UP LOADS IN YOUR GUN! Start low, etc etc etc. Lawyers are a player, but so are we...

Too soon old, too late smart.

[45crittergitter]

They aren't conservative. You are liberal. ;)

[delta5]

I have noticed that Lees manual shows beginning charges and actually I have to go up a half size on the disc thrower to get the listed amount. They back these numbers off on purpose, I assume...

[Cosmoline]

Why other books don`t give similar info is anyones guess

Because when you pay $100 for a small box of A-Squares you are prepared to invest some time reading up on them.

[qajaq59]

Why are reloading manuals so conservative? I'm not altogether sure that they are really. They have huge labs and all kinds of engineers figuring it out, and I have a loading press and a scale. Somehow I think they might know more about it then I do. And at least if they are wrong. it's on the side of my not blowing up a rifle.

[twice barrel]

How much freebore in your barrel? Did you load max charges with nearly flat primers in January and now going after prairie dogs in July?

As pointed out already - you need to be savvy enough to recognize signs of pressure in your own gun. What if you work up loads with a batch of hard primers only to make another batch with soft primers?

Why push it?

TB

[Remo-99]

And at least if they are wrong. it's on the side of my not blowing up a rifle.

I recently seen data from a reputable source (from a major powder company) and it showed max data for pushing a 55gr bullet at +4,000fps from a 17 remington.
Just a typo I'm sure, but say it was powder weight or type that was way off in error, and being used by a new reloader?
Sure pays to cross check data with after data from different sources.

[qajaq59]

Sure pays to cross check data with after data from different sources. That a chunk of advice that I hope every Newbie reads and follows!!!

[Galil5.56]

They have huge labs and all kinds of engineers figuring it out, and I have a loading press and a scale.

Maybe some do, but you would have gotten a kick from seeing the Accurate Arms "lab" from the the early 1990's. Prior to my job offer from them, I toured the "lab", part of which was an older single wide trailer filled with dies and Lee Turret/single stage presses. The actual testing area as I recall had just gotten new piezo test equipment, with older test barrels stacked to one side. I found the packaging area the coolest, where in a metal shed a few ladies with scoops and scales were hand filling bottles from big imported cardboard cylinders.

In no way am I saying anything negative here, just that if anyone thinks these labs are filled with white coat workers in pressure regulated clean rooms carrying out their work, well, certainly not in my experience. Much of it is tedious, low tech, but very concise and methodical.

[USSR]

Quote:
Why are reloading manuals so conservative?

I'm not altogether sure that they are really. They have huge labs and all kinds of engineers figuring it out...

Try calling Sierra sometime, and ask them what the pressure is on one of their "Max" loads. They will tell you they don't know, they just decided to stop there. So much for huge labs and engineers.

I think another reason for being conservative in manuals is probably more general purpose. The manuals are written for a broad audience with a wide variety of experience levels and whose equipment will have varying levels of precision.

People on this board use everything from Lee loaders, dippers, to progressive machines, and precision scales that cost hundreds of dollars. Quality of firearms used with these loads will also vary from poor to outstanding.

From a responsibility aspect this necessitates being more conservative.


Yep.

Don

[Byron]

I have used Speer #10 and Sierra #2 for years.I work up the loads and stop before max. The key is working up the load. If I am not mistaken, the Speer
#11 or 12 used a max load for 357 mag and Olin 296 below what the minimum charge was per Olin. Byron