9mm +p


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Hondo 60
January 17, 2011, 11:58 PM
Is there a SAAMI spec for 9mm+P?

I keep hearing about +P ammo, but have found no data anywhere.

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RidgwayCO
January 18, 2011, 12:07 AM
IIRC, standard 9mm has a maximum average pressure of 35,000 psi, while +P is 38,500 psi.

1SOW
January 18, 2011, 12:41 AM
As RidgewayCO said: Yes

+P+ has no SAAMI/CIP specs.

bds
January 18, 2011, 12:47 AM
Download this SAAMI PDF for centerfire pistols and revolvers (http://www.saami.org/specifications_and_information/publications/download/205.pdf).

It covers 115 gr 9mm +P on page 15 (PDF page 23):

9mm Luger +P, 115 JHP, 1235 fps, 38,500 PSI (maximum average pressure)

Page 21 (PDF page 29) has cartridge and chamber drawings/measurements.

Hondo 60
January 18, 2011, 01:17 AM
Thanks for the replies & the link!
So there IS a SAAMI spec for 9MM +P.

Then why no data for it?
I've looked at Hodgdon's, Alliant's & Accurate's websites and in Lyman's 49th & Lee's books.
No where have I seen any +P data.

ljnowell
January 18, 2011, 02:07 AM
Then why no data for it?
I've looked at Hodgdon's, Alliant's & Accurate's websites and in Lyman's 49th & Lee's books.
No where have I seen any +P data.


Probably because they dont want the liability of someone using a weak gun and blowing the heck out of it and blaming them for it. That would be my guess.

Also, this is just opinion, and ignore it if you will, but +p is pretty pointless. Usually its more pressure, in the case of 9mm about 3.5k, with a very small increase in FPS. Usually not nearly enough gain to make up for the increase in recoil.

cheygriz
January 18, 2011, 11:39 AM
Remember, most reloading manuals published in the last 20 years have been written by corporate lawyers, not by ballisticians. :(:(

"Maximum" charge weight (and performance) goes down every time a new class graduates from law school. :neener:

Ol` Joe
January 18, 2011, 01:09 PM
Remember, most reloading manuals published in the last 20 years have been written by corporate lawyers, not by ballisticians.

Actually they are written by ballisticians, just that better lab equipment is now being used. The legal department has no more say in the process then to push them to follow SAAMI guide lines for the cartridges.

A large percentage of reloading manuals were developed in the past with the same techniques to determine pressures as we handloaders are/were using at the time. Primer cratering, Case head expansion, excessive flattening of the primers, and sticky extraction were all employed. Bullet makers didn`t have expensive crusher barrels, universal receivers, and labs like todays. They made do as best they could.

Today the new strain systems are relatively cheap and much more accurate then the crusher method which only reacted to peak pressure over time and missed fast occurring events. Plus, the results could be skewed by the difference in how two proficient with a micrometer different techs were, and how accurately they measured the pellet and compared it to the tare table.

The different manufactures don`t want to admit another companies products can offer better velocity/performance and are not watering down their data. They report exactly what is found in their labs and the differences are due to variation in component lots or changes in the product, not lawyers. They follow SAAMI mandated standards today which are set by the developer of the cartridge, not SAAMI or the cartridge/component makers.

Some cartridges MAP `s have been reduced due to the age of the cartridge, and older weaker firearms out there. Others have been found to develop pressure spikes that the crushers used to develop loads in the past didn`t properly respond to, and are now loaded to reduced pressures to avoid them.
Loads developed by case head expansion have often been found to be off the mark when checked by strain systems and may have the charges reduced or even raised due to it.

New bullets have been added to the manufactures manuals over time, and change the data due to their presence. The books such as Speer, Hornady, Nosler, etc list loads by bullet weight, not by specific bullet. Sometimes this could be 5-6 different style, constructions and shapes of bullet. The data in the book is only valid for for the one that produced the most pressure with that specific max charge. The others obviously give less pressure, and the data may reflect a lower charge fr them due to the addition of the new bullet now being offered. That doesn`t mean the max isn`t valid for the older styles, we don`t know how much difference there actually is and they may be more similar then we believe them to be.

Then too it could be just the difference in the new lot of powder tested being at the fast end of the burn rate compared to the old data being built around powder that was on the slow end, or a new test barrel or change in primer brand, etc.
Ya never know...start low and work up. Trust the book, and if you have a crony use it. Comparing those two pieces of reference are the best judges of where you`re at pressure wise you have. :)

cheygriz
January 18, 2011, 01:24 PM
Joe,

I respect your opinions, but I most emphatically do not agree with them.

45 years od experience with an Oehler chronograph, maximum loads, and never a problem tells me that the "old" methods worked quite well. And the bigger outfits like Lyman, Sierra, Speer etc did indeed have "crushers" and pressure guns.

(:D :D BTW, perchance are you an attorney??:D:D:D )

Steve C
January 18, 2011, 02:45 PM
Data in the manuals for the 9mm is not listed as +P, not because of lawyers but because its not needed. Since you can easily achieve or exceed +P velocities for the 9mm as published by the manufacturers for their ammo with published hand load data, the fact that the data isn't listed as +P is inconsequential. The 9mm has always been a high pressure cartridge and all the firearms made for it where designed for the pressure it generates.

IMO 9mm+P is a manufacturing marketing gimmick. I can remember when the +P designation didn't exist in the 70's and the ammo you could buy then wasn't any less potent. Ammo that's called +P today used to be called "Hi Speed" or "police loads".

The only place where +P data is listed in hand loading manuals is for century old cartridges still in use that where originally black powder and there are still older firearms that are unable to take higher pressures due to metallurgy or condition while shooters of modern firearms want the better performance they offer. Examples would be the .38 spl and .45 Colt.

Clark
January 18, 2011, 02:56 PM
Look at the progress in the 35 years between between 47 years ago and 12 years ago:

"Speer 6" 1964 38 s&w special 160 gr. soft point 11 gr. 2400
"Speer 6" 1964 357 mag 160 gr. soft point 15 gr. 2400
Midway "Load map" 1999 357 mag Speer 160 gr. soft point 10.9 gr. 2400


How can 357 mag max has gone below 38 Special?

The "Load Map" says they used an "Oehler System 83 and piezoelectric transducers, the latest
in industry standard equipment".

For those with common sense..
This is nuts.
This is a wrong turn.

For those obsessed with process...
This is progress.

highlander 5
January 18, 2011, 03:09 PM
Isn't NATO spec ammo considered +P? Myself if I wanted more velocity I'd get a barrel for 9x21.

GLOOB
January 18, 2011, 05:42 PM
What would a 9x21 barrel do for a handloader? Unless you're talking about a .45/1911 platform, it wouldn't change the max OAL or case capacity except with extra light bullets. All it would do is provide a little more neck tension and make your brass 5 times as expensive.

Steve C
January 18, 2011, 07:06 PM
Look at the progress in the 35 years between between 47 years ago and 12 years ago:

"Speer 6" 1964 38 s&w special 160 gr. soft point 11 gr. 2400
"Speer 6" 1964 357 mag 160 gr. soft point 15 gr. 2400
Midway "Load map" 1999 357 mag Speer 160 gr. soft point 10.9 gr. 2400

But put into context the 160gr Speer bullet hasn't been in production for quite a few years and the data in the Speer #13 lists 14.8grs of 2400 as max for the 158gr jacketed bullets. Not much difference for 40 years.

Speer did stop listing data for heavy bullets over 140gr for the .38 spl. as they felt that you can't get enough velocity from the heavier bullets in the .38 spl. Latest Speer data I have showing the 160gr SP bullet was published in 1993 and it listed 10.0grs of 2400 as max +P load using magnum 550 primers.

onebigelf
January 18, 2011, 07:51 PM
Wow. Some interesting suppositions. The data listed in most manuals includes pressure data and is well below the maximum standard pressure of 35,000psi, much less +P pressures of between 35,000 and 38,500psi. It is, therefore, not +P data. There is a point of diminishing return. The powder charge data for one powder I load with goes from 6.2gr to 6.9gr and picks up 100fps at a cost of 6600psi, topping out at 1392fps and 36,300psi.

John

918v
January 19, 2011, 01:19 AM
I load my 9mm to -P- levels because target loads are more fun.

cheygriz
January 19, 2011, 12:16 PM
Highlander 5,

Yes, NATO spec is +P. However, that's according to SAAMI. In Europe, CIP standards consider ammo "normal" or "standard" pressure at the same levels we call +P.

Ol` Joe
January 20, 2011, 12:35 AM
Joe,

I respect your opinions, but I most emphatically do not agree with them.

45 years od experience with an Oehler chronograph, maximum loads, and never a problem tells me that the "old" methods worked quite well. And the bigger outfits like Lyman, Sierra, Speer etc did indeed have "crushers" and pressure guns.

cheygriz I don`t doubt you have never had a problem with the old methods. I too have been stuffing powder in cases since the mid 60`s and can only say I`ve had 1 problem with a load using primers, case expansion, extraction, etc as a guide. That one resulted in a stuck case in a 45LC Ruger Blackhawk that also locked up the cylinder due to the case head being jammed back tight against the rear of the action. No damage was done though, and pulling the remaining bullets never reveled the cause. The load was near, but not at book max.

I`ve heard that pressures need to be around 70K PSI piezo for primers to show cratering and flatten excessively. This is 5K psi more then the hottest rifle loads as set by SAAMI. Primers that don`t flatten at 35K psi in your safe and 44 mag load can`t be expected to show problems at 25-30K psi overloads in your 45acp or 44 spcl. Todays newer cartridge styles like the 223/308 or WSM`s with their straighter walled brass doesn`t stick bolts like the old tapered ones did either.
The case is the weakest link in the system and as long as it holds we think we are within safe SAAMI specs. We may be on safe ground as far as the case not rupturing, but we are not always within SAAMI specs. Thankfully the modern firearms and brass is better then it needs to be, and we get away with it.

A bit of info though that you might find interesting on how manuals arrive at their data,

The Speer#10 manual on pg 107 states,
"Over 20 pressure test barrels were added for this #10 manual, and much of the data is now computer processed ( anyone think "Quick load"?). Over 35,000 rounds were loaded, fired, and measured in some way for the revisions and additions to the loading data.

Then further on pg 108;
"Where pressure barrels were not available - all of the wildcat and foreign cartridges, and some of the older less popular standard US cartridges- loading data was developed using the primer- appearance/case-extraction-head expansion methods.":confused:

This manual was published in 1979 and they were just moving to "pressure barrels and computer models for their data, or so it sounds.

The Hornady 5th edition published in 2000 on pg 70 states "When possible, loading data was fired in a special firearm designed to measure pressure. There is a description of a pressure gun in the Illustrated Glossary" (the glossary shows a crusher gun not the modern strain system)

The newest, just out this month, Hornady 8th edition on pg 78 seems to say Hornady is still in the process of moving to the latest test equipment.

"In some calibers and for some cartridges, pressure barrels were not available. We developed and tested loads in these situations by employing a factory or custom firearm and examining the brass case and the fired case extracted from the chamber. The brass case will show several indications of increasing pressures. One is case head expansion as measured by a good micrometer and compared to a fired, factory loaded cartridge. Other pressure signs of significance were cratered or flattened primers, brass flow into ejector slots, case head expansion, as well as difficult case extraction.
We employed the procedures above only when we had no other options. The vast majority of the data in this book was derived from the use of strain gauges"
Hornady by their own mouth is still using the old methods in some instances

I`ve heard it repeated by too many writers and industry people that todays data changes are due to improved pressure measuring and not lawyers. I can`t believe they all are lying.
Old data was developed by Crusher and the pressures were listed in CUP or LUP depending on the cartridge. later they tried saying CUP was the same as PSI and simply started changing the CUP label to psi. Today we know the difference and PSI is used where it is relevant, with strain measurements, and old crusher data is still listed in most cases as CUP, or no pressure is given for the load. Hodgdons web site is a good place to see this.

Compare a couple different manuals, all modern with data listed for the same bullet and powder. I think you`ll find the velocity of each load falls with in what can be expected to be the extreme spread of the load in most cases, no matter what the powder charge is. they all load to max and all get similar results with the same components

There are a few cartridges out there though, that SAAMI dropped the max pressures slightly on over the years due to spikes or other perceived problems with the higher psi level. The 7mm Rem mag, and 44 mag, are two of them. I think the 357 mag is another. These I can agree are lower due to legal or manufacturing problems of some type. They are not the reason for most of the lowed charges though, and the change and reasoning was published when they happened in a few magazines.

Clark
January 20, 2011, 01:23 PM
"There are lies, damn lies, and then there are 7mmRemMag published loads." -What Mark Twain should have said.

I can get more power than that, with long brass life, from 7x57mm Mauser.

deacon8
January 20, 2011, 01:38 PM
Clark,

Are you referencing something? I'm not trying to be a moron. Sorry if I just overlooked something, or don't get it. The 7X57 Mauser is my favorite cartridge and I reload. So based on that, I am interested in what you are talking about.

cheygriz
January 20, 2011, 01:49 PM
Joe,

I definitely agree that we've made enormous progress in measuring. No question of that. Case head miking can vary according to the hardness and/or thickness of the brass. (although it can still be valid if several different brands of case are used.)

I've never used primer appearance as an indicator, since cup thickness and hardness varies wildly, IME.

But I do believe that "crusher" measurements, while less precise than strain guage measurements were (and still are) valid.

My primary guides to whether or not I was "over-pressure" on a load has always been velocity and case life.

If several manuals say that a particular load makes 1000 FPS, and my load makes 700, or 1300, I know something's wrong.

Also, if I can reload cases from several different manufacturers more than 5 times, I pretty well know my load is safe. If primer pockets start getting loose after one or two loadings, I back off, regardless of whether or not the manual says it's okay.

Most of my loading for pistols is +P or +P+, so I always exersize extreme caution working up loads. I re-work a load when changing lot numbers of the same powder.

My heartburn with the modern manuals, is that for most of the calibers I load in volume, they have cut the maximum velocity as well as powder charge. With so many new powders available, there's no reason to sacrifice performance.

(OTOH, perhaps my rather intense dislike of most (not all) lawyers has colored my judgement! :D:p:D )

Clark
January 20, 2011, 02:30 PM
deacon8
Clark,
Are you referencing something? I'm not trying to be a moron. Sorry if I just overlooked something, or don't get it. The 7X57 Mauser is my favorite cartridge and I reload. So based on that, I am interested in what you are talking about.

I am talking about comparing reality to published load data.
If I work up to the threshold of short brass life, and back off an engineered and verified safety margin, the practical performance can be realized and compared to the performance of max published loads shot over a chronograph.

Different cartridges are getting cheated different amounts.

The 1889 7.62x53mm Mauser case head design, when built with a large rifle primer pocket has the same real limit for 270 and 8x57. One cartridge may be SAAMI registered at 65,000 psi and the other at 35,000 psi, but they are capable if the same pressure for long brass life in a strong rifle.

Using that technique for the 7x57mm and comparing to a 7mmRM loaded with max published load, same barrel length, over a chronograph, the 7x57mm will win.

But the 7mmRemMag case head is stronger and the case holds more. How can it loose the contest?
It is because of the lameness of 7mmRemMag published load real results.

I get 3025 fps 180 gr from my 7mmRemMag and that is way down into the long brass life and WAY WAY WAY above max published load results.

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