"+P" history

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Guillermo

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Greetings fellow THRers

We all know that the SAAMI specs were lowered for .38 special in 1972 (?). The old "regular" pressure ammo became "+P". "regular" ammo was emasculated.

Is this the case for other cartridges as well?


Would someone with the old manuals post the pre-72 specs for other popular handgun cartridges?

Thank you in advance

G
 
I know that factory 38 Super was downsized. Originally it used a 130 grain bullet at around 1270 FPS. Supers were always loaded in nickel cases to distinguish them from the 38 ACP which is dimensionally the same but loaded to around 1050 FPS. A few years ago I noticed Super ammo coming in brass cases. I clocked it and sure enough it now runs 1080 FPS. I assume this was done on advice of counsel out of fear of an older 38 ACP gun being loaded with 38 Super ammo which USED to be loaded to much higher chamber pressure.

I believe that the 357 and 44 Magnum revolver ammo has also been watered down from original loadings. But I have not studied this to be sure.
 
Got my first 44 mag in 1974 & the standard Remington load was a 240gr lead gas check which they advertised at 1470. I didn't have a chrono then (nor much else), but you can't find a load even close to that today.
 
In 1974, SAAMI introduced the +P standard to a few select calibers.

257 Roberts = 54,000
257 Roberts +P = 58,000

9mm = 35,000
9mm +P = 38,500.

.38 Spl = 17,000
.38 Spl +P = 18,500.

Colt .38 Auto = 26,500.
.38 Super +P = 36,500.
(.38 Auto & .38 Super are the same size case. +P designation was added to the Super to avoid confusion)

.45 ACP = 21,000.
.45 ACP +P = 23,000.

rc
 
It varied by caliber.
.257 Roberts +P was standard pressure before 1974.

9mm +P is more similar to WWII German surplus IMO:
American ammo was loaded way lighter then that up until then.
I owned more then one Luger in the 60's that wouldn't cycle reliably with American ammo.

As of 1975, .38 Spl standard pressure was 18,900 CUP, +P was 22,400 CUP.
As of 1998 it was 17,000 PSI and 20,000 PSI.
As of today it is 17,000 PSI & 18,500 PSI.

.38 Super didn't change much if any.

.45 ACP +P seems to me to be the only one with much if any performance improvement.

rc
 
I think that another thing that has happened over the years was a standardization of test barrel lengths. now for most revolver rounds the standard barrel length is a 4 inch vented barrel. years ago you had to look at the ammo company catalogs to see what the barrel length was used. some of the revolver rounds were tested in 10 inch unvented barrels and that is going to give a much higher velocity than the 4 inch vented barrel. after all velocity sells.
 
Here is a scan from my Speer #6 1964 and Lyman's #44 1967 editions.
 

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In addition to standardization of tests, there have been changes in powder formulations, primers, and evolvement of bullets. The 158gr JHP, .357, is not the same bullet that was made in the 1970's.
 
"As of 1975, .38 Spl standard pressure was 18,900 CUP, +P was 22,400 CUP.
As of 1998 it was 17,000 PSI and 20,000 PSI.
As of today it is 17,000 PSI & 18,500 PSI."

Thanks for that info, rcmodel. It would seem I should be able to use current manufacture +P ammo in my 1950's Colt Trouper revolver without damaging it in any way compared to standard .38 cartridges.

Would you agree - or am I missing something?
 
Correct me if I am wrong.

But the Colt Trooper is a .357 Magnum to start with.

.357 is rated at 35,000 PSI.
So any .38 Spl ammo you can buy is only about 50% of the pressure the gun was designed for.

rc
 
I've heard of .357 Troupers but mine came from my uncle after he passed. He was a prison guard in the federal system and the revolver is marked .38 special.
It certainly looks strong enough for .357 magnum so I presume these were made for the government. That's all I know about them.
 
O.K. so you do have a .38 Spl. Trooper!
Thats special!!

Still, I would have no worries about shooting todays +P in it if it were mine.

It was designed from the getgo as a .357 Magnum on the old Colt medium I-frame.

rc
 
RC is, of course, correct.

That said, even if it were a frame designed for .38 spl, which it isn't, +p is he same pressure as the "regular" ammo from before 1974.

A trooper was made to be a .357. It yawns when u shoot .38s
 
Well, I got my wires crossed.

The Trooper was a .38 Spl. in the beginning.

Later refined into the .357 Trooper, .357, and Python.

Still it is a fairly strong gun based on the old Colt .41 cal frame, and I would have no problem with +P in it.

Back then, there were .38 Spl Hi-Speed loadings that almost put todays .357 loads in the shade and a lot of cops used them in guns just like that one.

rc
 
I just read up on it

RC is batting 1000

Until 1961 .22lr. .38 and .357 troopers were available.

Not special order.

38 Trooper is like a .38 Anaconda...WAY overbuilt
 
Thank you all. It's good to know that I can safely use +P for home defense.
 
Why did they down load? Less wear on the revolver?

Given this information, am I wrong to assume that this means that modern +P rounds can be safely fired in an older .38 special revolver, even if it wasn't originally rated for +p?
 
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