9mm +P+ pressures?

[jski]

I’ve been reading and hearing people talk about 9mm +P+ ammo generating 45,000 PSI pressure levels. Any truth to that? That would put it at Federal 327 Magnum levels and the 327 is riding the edge.

Wouldn’t those pressure levels tear most 9mm pistols to pieces?

I’m dubious.

 

[mcb]

+P+ has no specification from SAAMI. I don't believe any other organization (like CIP) has a specification for +P+ either.

 

[jski]

+P+ has no specification from SAAMI. I don't believe any other organization (like CIP) has a specification for +P+ either.

I suspected that but is there any published data on these loads? 45K psi in a revolver is one thing but in an autoloader it’s quite another.

And as I said, the Federal 327 Magnum is riding the edge at 45K. There are numerous reports of flattened primers from Federal’s factory loads. Though I have to believe those rounds are completely safe coming from Federal. They have way too much at stake to risk anything.

 

[mcb]

I suspected that but is there any published data on these loads? 45K psi in a revolver is one thing but in an autoloader it’s quite another.

I don't think you will find any official publish data for loads that go over SAAMI by the powder/bullet etc manufactures with the exception of 45 Colt and 45/70. SAAMI specs exist for a reason, to keep us safe and them from being sued.

That said there is lots of data out there that goes over SAAMI spec for various cartridges by various specialty groups. USPSA Open competitors are pretty "famous" for going well over 40K with 9x19mm to make Major power factor, especially in guns with barrel ports close to the chamber. It's been nicknamed 9mm Major. So if you looking for hot 9mm might look to USPSA Open shooter data (Brian Enos Forum would be a good starting place) for some "+P+" 9mm data to play with. I personally would not shoot that stuff in a regular 9mm gun, the USPSA Open guns are setup to deal with these high pressures and the loads are worked up for each gun typically.

 

[AK103K]

There may not be a specific SAAMI rating for +P+ 9mm, but some of the big makers seem to have an idea as to what it is. Speer does anyway.

I sent them an email asking about the difference between +P+ and 357SIG when I was into that round, and was told that they both were a 40K psi round, and with bullets of equal weights, would more or less give the same results.

So it sounds like Speer looks at +P+ 9mm being 40K psi. Im sure Winchester and a few of the others that made/make it, know what theirs is as well, even if SAAMI doesnt want to rate it. Cant say if one of the others isnt running at 45K, but from what Speer was saying, there is no +P+ 357SIG, and 40K psi is the max pressure for it. Kind of doubt 9mm would surpass it.

 

[Rule3]

But the real question is WHY? What good is a 9mm+P+?

 

[fxvr5]

Some semi-auto pistols will handle the high pressure with no problems. As noted, 357 Sig runs 40,000 psi. 9mm +P is 38,500 psi, which is close. But other rounds have even higher pressure.

356 TSW has a maximum limit of 50,000 psi. It is a 9mm-OAL round designed to make major power factor for IPSC/USPSA right out of the box. It did, and still does. A 115 grain bullet at 1600 fps, a 125 grain bullet at 1450 fps, and a 147 grain bullet at 1220 fps - from a 5" barrel.

The 356 TSW is a good example of what you can do with a 9mm Luger since they both have the same OAL.

Then there is the 9X23 Winchester. Also designed for major power factor for IPSC/USPSA, it has a 55,000 psi limit. It pushes a 124/5 grain bullet to 1450 fps, and was designed to do so from an unsupported chamber. The 9X23 is the same length as a 38 Super. Proper powder selection will get those speeds and well below the 55,000 psi. A 38 Super can get that speed with 124/5 grain bullets within it's normal operating pressure (36,500 psi) by selecting the right gunpowder - N105 is very good for this purpose.

Here is information on 9 Major for people who want a more info:

https://americanhandgunner.com/discover/whats-9-major/
https://www.ssusa.org/articles/2018/1/9/how-to-use-9-major-in-a-short-barrel/

 

[fxvr5]

I suspected that but is there any published data on these loads? 45K psi in a revolver is one thing but in an autoloader it’s quite another.

Chamber walls in revolvers can be very thin, and they can be thicker in a semi-auto. My S&W j-frame 357 Magnum cylinder wall measures 0.055". My S&W M&P9 9mm chamber wall measures 0.100". Both have a pressure limit of 35,000 psi. People build 9 Major guns with the M&Ps.

 

[fxvr5]

Also consider that SAAMI proof pressures for the 9mm Luger 55,500 psi (maximum).

Proof pressure for the 356 TSW is 72,000 psi, and for the 9X23 Winchester it's 79,000 psi.

Other than pressure what some of the 9mm +P+ - like cartridges offer is more recoil. But even that isn't that bad.

A 9X23 Winchester pushing a 125 grain bullet to 1450 fps produces 5.81 ft lbs of recoil in a 2.25 lb gun.

That's the same as a 45 Auto, which with a 230 grain bullet at 850 fps makes 5.82 ft lbs of recoil.

 

[golden]

Until the ammo makers agree on a pressure limit and standardize it with SAAMI, +P+ will just be whatever pressure it takes to get a certain performance goal.

From a liability standpoint, they will probably not want to. You know as soon as they decide to create a +P+ standard, some fool will load this stuff in his old ASTRA 600 and blast away till it breaks into pieces. At least that is what I think their lawyers will tell them.

The 9m.m.+P+ ammo that I was issued, was issued by my agency and they would probably been held liable, if the guns and those using them were damaged. They wanted a certain level of performance and our field results showed that we got it.
The pressure for those loads was probably only slightly higher than hot loaded +P ammo. I found it hard to tell the difference when shooting them side by side. It was much easier telling standard velocity ball ammo from +P+.

Jim

 

[FL-NC]

My mags are loaded with it. But since they are for Glocks, I'm not concerned about the guns coming apart.

 

[Jim Watson]

The pressure for those loads was probably only slightly higher than hot loaded +P ammo. I found it hard to tell the difference when shooting them side by side. It was much easier telling standard velocity ball ammo from +P+.

Federal 9BPLE +P+ is well regarded. I think it is like that, just a slight overload to get a 115 gr jhp to 1300 fps.

9mm standard is 35,000 ppsi MAXIMUM, +P is 38,500 ppsi MAXIMUM.
But not every round is crowding the maximum. Lots of reload data giving good velocity at say 32,000 ppsi.
Technically speaking 35,001 ppsi is +P and 38,501 ppsi is an overload, commonly called +P+. Well, not exactly, there is some statistical massaging to be done, but the point is, anything over one level takes it into the next, it doesn't have to go all the way to the top.

 

[IdaD]

I've run some +p+ Gold Dots and they functioned fine although they felt about like shooting 40. I didn't notice they were +p+ when I ordered them and I ended up storing most of them away for a rainy day. I don't think they'd hurt anything unless maybe I shot a bunch of them.

 

[Mr. Zorg]

Wikipedia (always a dubious source) cites one of its sources lists 42Kpsi for 9mm+P+

"The +P+ designation is not currently used by the SAAMI, but is used by some manufacturers to designate loads that exceed the +P SAAMI specification. One source lists the 9 × 19 mm +P+ loading as having a pressure of 42,000 psi, a 20% increase over the standard pressure of 35,000 psi, and the .38 Special +P+ as 22,000, a 29% increase over the standard pressure.[5]"

https://en.m.wikipedia.org/wiki/Overpressure_ammunition

So 45Kpsi doesn't appear unreasonable

 

[Meeks36]

I have three boxs of federal +p+. Waiting to buy a hipoint carbine to run them through. When this panic ends ill pick one up. Don't want to risk hurting my Ruger PCC.

 

[Rock185]

jski, whatever the actual pressure, I have used a fair amount of 9MM +P+ in a variety of semi-autos and revolvers. That would include Winchester 115 and 127 grain +P+, Federal 115 +P+, and Remington 115 +P+. I've also used the new Winchester M1152 115 grain flat point ball ammo, created for the military, that I suspect is loaded to similar pressures since chronographed velocities are similar to +P+ ammo of the same weight. I have not torn any 9MM pistols to pieces. Actually, I've not experienced any broken, bent, or deformed parts, nor have I been able to detect any premature wear.

FWIW, CorBon 115 grain JHP ammo, only rated as +P, routinely produces velocities equal to or higher than any of the +P+ I've chronographed. The CorBon I've used was manufactured prior to CorBon's change of ownership, so I don't know how the current owner's ammo performs...

 

[Riomouse911]

I have been issued the Winchester SXT as duty ammo since I moved to my current employer 15 years ago. I’ve shot gobs on the range, and I have gobs on the shelf, of the 127 gr +P+ and 124 gr +P ammo from Winchester. None of the guns that I fired hundreds of these through; a Glock 19 and a Glock 34, or my more recently purchased Ruger PC9 that has fired about 100 +P+ through it, show any wear other than from normal use.



I don’t know what the pressure is, but I can’t tell any real-world difference on the shooter-side in recoil or noise between the 127 +P+ and the 124 +P Ranger SXT.

Stay safe.