Hey guys, anybody have any old-school SAAMI pressure charts? Maybe even something from when they got started in 1926? I’m sure many of you are aware that SAAMI’s recommended max average pressures have slowly dropped over the last 50 years for some cartridges and since I’m a knowledge hog I wanted to take a look at what was considered safe in decades past. I’m specifically interested in pistol rounds. Thanks!
-
Update – 12:30 PM EST
Attachments are now working, and all members can once again upload files.
We are currently testing URL redirects and other miscellaneous features across the site.
Thank you for your continued patience and support during this migration.
Prefer a darker look? You can switch between light and dark modes in your account settings:
smith-wessonforum.com/account/preferences
Old SAAMI Specs for pistol ammo??
- Thread starter Distorto2
- Start date
Alk8944
US Veteran
First, it is basically a myth that pressure limits have been reduced as you say. The major reason is the method of measuring pressures changing. There are basically three different ways of expressing chamber pressures:
Copper (or Lead) crusher interpreted/expressed as PSI based on shortening of the crusher slug compared to a tarage table.
Copper or Lead crusher interpreted/expressed as CUP or LUP. This is just a different way of expressing the pressure from above.
Piezo-Electric pressure testing. This is based on the electric current generated when a piezo electric crystal is compressed.
The reality is that regardless, you DO NOT have pressure testing equipment of either type, so the question is totally moot! You still have to depend on published data to have any idea what pressure your loads develop, or, at least, a chronograph to tell you what velocities your ammunition producer. Anything further pressures you are simply guessing, which can be extremely dangerous, or at best expensive from damage to your firearms!
And, pressure/velocity data published in various loading manuals/sources really mean nothing when they are compared one to another as what their loads were shot in, test barrel length, method of testing, etc. vary from company to company so there is no direct comparison!
Current SAAMI/CIP pressure standards are as close as you can get. Because they both use closely controlled procedures their results compare to each other very closely!
All said it is my experience having reloaded for more than 60 years, that the most accurate data you will find compared to chronograph data, assuming you have a chronograph,!!! is the data published by the propellant manufacturers instead of reloading equipment or bullet manufacturers.
Copper (or Lead) crusher interpreted/expressed as PSI based on shortening of the crusher slug compared to a tarage table.
Copper or Lead crusher interpreted/expressed as CUP or LUP. This is just a different way of expressing the pressure from above.
Piezo-Electric pressure testing. This is based on the electric current generated when a piezo electric crystal is compressed.
The reality is that regardless, you DO NOT have pressure testing equipment of either type, so the question is totally moot! You still have to depend on published data to have any idea what pressure your loads develop, or, at least, a chronograph to tell you what velocities your ammunition producer. Anything further pressures you are simply guessing, which can be extremely dangerous, or at best expensive from damage to your firearms!
And, pressure/velocity data published in various loading manuals/sources really mean nothing when they are compared one to another as what their loads were shot in, test barrel length, method of testing, etc. vary from company to company so there is no direct comparison!
Current SAAMI/CIP pressure standards are as close as you can get. Because they both use closely controlled procedures their results compare to each other very closely!
All said it is my experience having reloaded for more than 60 years, that the most accurate data you will find compared to chronograph data, assuming you have a chronograph,!!! is the data published by the propellant manufacturers instead of reloading equipment or bullet manufacturers.
Last edited:
DWalt
Well-known member
At least in the western world, there are three different pressure standards used - SAAMI, CIP, and NATO. All now use piezoelectric pressure transducers, but the methods of use differ. So firing of identical rounds of ammunition using those three methods will produce three numerically different pressure results.
It is doubtful if any halfway modern ammunition manufacturer on Earth still uses the old copper crusher pressure measurement method. It is literally a relic from the Stone Age. But that was about the only pressure measurement method available until the 1950s-1960s.
The early SAAMI standards based on the use of Copper or Lead crushers are no longer applicable, at least not from an ammunition manufacturing perspective.
It is doubtful if any halfway modern ammunition manufacturer on Earth still uses the old copper crusher pressure measurement method. It is literally a relic from the Stone Age. But that was about the only pressure measurement method available until the 1950s-1960s.
The early SAAMI standards based on the use of Copper or Lead crushers are no longer applicable, at least not from an ammunition manufacturing perspective.
Last edited:
Thanks for the info guys! I’m definitely not one to push the limits, I just like to educate myself. What you’ve both stated confirms what I’ve read elsewhere: that it’s not so much that the actual recommended pressure limits have changed, but it’s the methods that have changed, providing more accurate results. Correct?
LVSteve
Well-known member
Yes. I recall reading that the real peak pressures occurring in many calibers of handguns ammo using fast powders revealed by modern piezo-electric transducers came as a bit of a shock to ammo and gun makers alike. The copper crusher methods were incapable of showing what was really going on. This undoubtedly led to changes in loadings that gave reduced velocities. Many complaints about neutered 38 Spl and 357 Magnum followed.
- Joined
- Feb 3, 2015
- Messages
- 1,323
- Reaction score
- 1,532
Another source of the myth that old ammo was much more powerful is affordable chronographs. Which by strange coincidence became available at the exact same time many people believe ammo makers started watering down their ammo.
gwpercle
Well-known member
Pick up a copy of the Speer Manual for Reloading Ammunition ,
Number 8 , first printing June 1970 ...
Check out some of the maximum handgun loads listed .
I had started reloading in 1967 with rifle data from Hornady , in 1970 I got a 357 Magnum Blackhawk and the brand new Speer reloading manual (the Hornady #1 manual had No handgun data) and just knew Speer was the place to get reliable data !
I'm glad my 357 was a Blackhawk ... Heck for Stout !
They may have been a little warm but I still use several of those old Speer Handgun loads ... as my pet loads !
Gary
Number 8 , first printing June 1970 ...
Check out some of the maximum handgun loads listed .
I had started reloading in 1967 with rifle data from Hornady , in 1970 I got a 357 Magnum Blackhawk and the brand new Speer reloading manual (the Hornady #1 manual had No handgun data) and just knew Speer was the place to get reliable data !
I'm glad my 357 was a Blackhawk ... Heck for Stout !
They may have been a little warm but I still use several of those old Speer Handgun loads ... as my pet loads !
Gary
rockquarry
Well-known member
- Joined
- Aug 9, 2005
- Messages
- 8,484
- Reaction score
- 10,411
Along the same lines, look at several of the old Speer data books from the '60s and maybe early '70s. Tables show actual muzzle velocities recorded by Speer vs. advertised published figures from ammo manufacturers for many rifle and handgun cartridges.
I realize many today are opposed to buying handloading manuals because they think everything is available on line. It's not and these folks miss out on a lot of good and credible information without ever knowing it. It's best to use current load data, but the old manuals remain excellent reference sources.
Get more than one manual for handloading if you are serious. I started with a Lee Loader basic loader that came with one sheet of loading data for .357. They had a dipper and a list of powders. Those loads were pretty mild IMO but shot fine and were large safety margin. You will need several manuals for a larger variety of powders plus you can see differences for the same loads and their results. You can get used manuals online either vintage or just a few years old at substantial savings on the auction sites.
Last edited:
Over the years I have loaded a lot of revolver and pistols loads,
from standard to +p loads , in a lot of my testing with different types of
powders and different weight bullets for my entertainment.
Fast to slow powders will work in all loads but you can get into trouble with both
if you try to push the envelope on the loading data.
Super fast & loud loads were fun when I was young but in my "Silver years",
I now load mostly light, accurate loads for my shooting.
Have fun and stay safe.
from standard to +p loads , in a lot of my testing with different types of
powders and different weight bullets for my entertainment.
Fast to slow powders will work in all loads but you can get into trouble with both
if you try to push the envelope on the loading data.
Super fast & loud loads were fun when I was young but in my "Silver years",
I now load mostly light, accurate loads for my shooting.
Have fun and stay safe.
stansdds
Well-known member
Yep, heavy charges of H-110/W-296 in magnum calibers provides plenty of boom and a dazzling light show, but they are hard on the hearing and the wrists. I'm just not that thrilled with such things these days.
I don't share the reverence stated above for powder manufacturers data. Some are accurate, some aren't. I've got a WW data book that apparently had magic barrels-at least for pistol data. OTOH, I've got Alliant rifle data that tracks well-at least for matching factory ammo velocities from the same gun. Reach the same velocities for a given charge......not hardly.
I used to belong to a now dead board where one of the members was a barrel maker. A large portion of their business was for test barrels. Those were requested with minimum bore, groove and chamber dimensions. The idea was to provide a worst case scenario for pressure testing load data. Naturally, this is gonna produce different results than we're going to see.
You do, very occasionally, run into a "fast" barrel. Not sure what the difference is. Probably bore & groove diameter, there's a 0.002 inch tolerance on most interior barrel dimensions. Plus/minus 0.001 on each side of nominal.
I used to belong to a now dead board where one of the members was a barrel maker. A large portion of their business was for test barrels. Those were requested with minimum bore, groove and chamber dimensions. The idea was to provide a worst case scenario for pressure testing load data. Naturally, this is gonna produce different results than we're going to see.
You do, very occasionally, run into a "fast" barrel. Not sure what the difference is. Probably bore & groove diameter, there's a 0.002 inch tolerance on most interior barrel dimensions. Plus/minus 0.001 on each side of nominal.
Last edited:
stansdds
Well-known member
I'd theorize that fast barrels are a result of perfect bore and groove diameter for the caliber and very smooth internal surfaces. Pistols and rifles might also have higher velocities with minimum sized chambers. Bore throat could also have an effect on velocity.
Case in point, a Bar-Sto 1911 barrel that I had. I had a budding gunsmith perform a little work on it. I had dialed in my ammo for USPSA major power factor minimum velocity plus 5%, but the chamber was so tight that I had to use only Federal brass, other brands of brass were slightly thicker near the case mouth. He ran a chamber reamer through it to open up the chamber a couple thousandths of an inch and recut the throat.
Unfortunately, he ended up cutting the throat so much that it now had about 1/2 inch of free bore. My ammo, which was producing velocities of 5% over the required minimum, now barely made major power factor velocity. He offered to buy me a new barrel, but the modified barrel was still very accurate and now 100% reliable, so I kept it and just increased my powder charge a tiny bit.
Case in point, a Bar-Sto 1911 barrel that I had. I had a budding gunsmith perform a little work on it. I had dialed in my ammo for USPSA major power factor minimum velocity plus 5%, but the chamber was so tight that I had to use only Federal brass, other brands of brass were slightly thicker near the case mouth. He ran a chamber reamer through it to open up the chamber a couple thousandths of an inch and recut the throat.
Unfortunately, he ended up cutting the throat so much that it now had about 1/2 inch of free bore. My ammo, which was producing velocities of 5% over the required minimum, now barely made major power factor velocity. He offered to buy me a new barrel, but the modified barrel was still very accurate and now 100% reliable, so I kept it and just increased my powder charge a tiny bit.
Except for Speer #8. Some of the .45 AR/ACP loads come to mind, but there are others. To the best of my knowledge, Speer produced that manual WITHOUT PRESSURE TESTING.
Jack Flash
SWCA Member
In addition to the above comments remember that in the distant past, velocity figures published by the ammunition manufacturers were, shall we say, very optimistic. Claims of high velocity no doubt correlated with higher sales.
With the advent of the widespread availability of chronographs, the numbers surprisingly became more realistic.
With the advent of the widespread availability of chronographs, the numbers surprisingly became more realistic.
- Joined
- Feb 3, 2015
- Messages
- 1,323
- Reaction score
- 1,532
These days there are so many people with chronographs manufacturers cannot get away with wildly exaggerated velocity claims although a little exaggeration is still very common.
But I have to wonder if the high cost of equipment to measure pressure is causing a similar problem with some boutique ammo makers going over SAAMI pressure limits to generate the extra velocity they rely on to sell ammo.
Underwood has a 158 grain hard cast 38 +P load they spec at 1250 fps with 548 foot-lbs of energy. Without independent pressure testing there is no way to know how hot that ammo is loaded but 357 Magnum velocity requires 357 Magnum pressure levels. Thanks to chronographs most shooters now know that ammo makers cannot be trusted to advertise accurate velocity ratings. But they still believe ammo makers can be absolutely trusted it comes to pressure specs.
Last edited:
gwpercle
Well-known member
I guess it was " The Good Old Days " ...
But maybe it was more a case of ...
" Ignorance is Bliss " !!!
But we sure had fun when Lee Jurras came out with his 110 gr. JHP's and with Speer #8 in hand ... we loaded them in 357 magnums ... water filled milk cartons were in danger of extinction around us young high school aged shooters .
I'm not going to state how much Unique was Speer's Maximum Load ... but we used it !
Gary
Last edited:
While the attitude of some boutique ammo makers is "Damn the pressures, high velocity ahead!" There's some wiggle room in SAAMI specs. So, even if they do perform pressure tests, they can claim with a straight face that their products "meet SAAMI specs."
Ammunition is supposed to be voluntarily limited to SAAMI MAP. I'd have to go down multiple flights of stairs to find out exactly how they determine that, memory suggests it's 2 standard deviations below one of the limits below.
Then there's a somewhat higher pressure limit for a given sample lot of ammunition.
Finally, there's a no round should ever exceed limit.
As an example, Stanag 4090 for NATO 9 mm has a MAP of 37,000 CUP, and a never exceed of 42,700 CUP (using their specified measuring system). So there can be a lot of wiggle room.
Ammunition is supposed to be voluntarily limited to SAAMI MAP. I'd have to go down multiple flights of stairs to find out exactly how they determine that, memory suggests it's 2 standard deviations below one of the limits below.
Then there's a somewhat higher pressure limit for a given sample lot of ammunition.
Finally, there's a no round should ever exceed limit.
As an example, Stanag 4090 for NATO 9 mm has a MAP of 37,000 CUP, and a never exceed of 42,700 CUP (using their specified measuring system). So there can be a lot of wiggle room.
Last edited:
Similar threads
- Locked
