[motovate]

I started a new discussion on +P and +P+ because on the previous 10mm discussion I was talking specifically about 10 MM. This one is about any +P or +P+ ammo not just limited to any one caliber loading's. Sort of laying the ground work - I have 2 - 9mm pistols and I was not having much luck finding any 9mm in Hornady's Critical Defense or Critical Duty. I actually did find some 115 grn @ Midway in Critical Defense and ordered some of it mainly because I was already carrying it in one of the 9's I have - wanted to remain consistent. I decided to look @ Buffalo Bore for 9mm since I just ordered some 10 mm from them - the 9mm was an after thought. I was surprised to see several +P+ loading's from Buffalo Bore. This made me curious because I thought +P+ was not being loaded much so I decided to do a little searching. What I have here is a link to a Firearm Tutorial titled "Ammo What is +P and +P+" and a little bit from that "Tutorial". I think it looks interesting, has some info and will likely light someones fire here bringing on good discussion. I haven't read it all yet and even when I do I will never claim I understand all of it. Here is the link - you might need to fiddle with it to get it to work - if you are interested - there is way more in the article. I have no idea if it is actually correct because I never heard of "Erik" who wrote it. There might be more about him later in the Article.

AMMO: what is +P and +P+

AMMO: what is +P and +P+

www.firearmtutorials.com

"A +P+ load is X percent higher than a +P load. SAAMI does not publish +P+ loads and therefore they are developed by each ammunition manufacturer. Again +P+ does not exceed the proof round.

Let's use 9mm as an example. Standard pressure SAAMI loads are 35,000 PSI while +P pressure is 38,500. Load data for +P+ is no specified by SAAMI, but the proof round value is 45,700 PSI. By deductive reasoning we can estimate a +P+ load of 42,000 PSI. "

Interesting??? To me it is. I have heard of proof rounds but really didn't give it a lot of consideration more then probably thinking it is where the round will come apart.

Make of it what you will I am just sharing something new to me that I just found.

Anyone know what the proof round PSI for 10 MM is???

 

[lklawson]

AMMO: what is +P and +P+

AMMO: what is +P and +P+

www.firearmtutorials.com

"A +P+ load is X percent higher than a +P load. SAAMI does not publish +P+ loads and therefore they are developed by each ammunition manufacturer. Again +P+ does not exceed the proof round.

Let's use 9mm as an example. Standard pressure SAAMI loads are 35,000 PSI while +P pressure is 38,500. Load data for +P+ is no specified by SAAMI, but the proof round value is 45,700 PSI. By deductive reasoning we can estimate a +P+ load of 42,000 PSI. "

This is, at best, a misleading statement. At worst, it is flat out wrong. No one publishes what their +P+ pressures are. We do not know if they exceed a "proof" cartridge or not. They might or they might not.

That said, what's the point? Are you making some assumptions about the safety or advisability of using "proof" cartridges in firearms?

Peace favor your sword,
Kirk

 

[1024Megabytes]

Anyone ever fired +P+ ammo through a firearm? I cannot remember the last time I saw +P+ ammunition being sold at a gun store.

 

[lklawson]

Anyone ever fired +P+ ammo through a firearm? I cannot remember the last time I saw +P+ ammunition being sold at a gun store.

I'm pretty sure that IV8888 did when they were <cough> "testing" the C9. But they had to custom hand-load the cartridges.

Peace favor your sword,
Kirk

 

[ajole]

Buffalo Bore. This made me curious because I thought +P+ was not being loaded much so I decided to do a little searching. What I have here is a link to a Firearm Tutorial titled "Ammo What is +P and +P+" and a little bit from that "Tutorial". I think it looks interesting, has some info and will likely light someones fire here bringing on good discussion. I haven't read it all yet and even when I do I will never claim I understand all of it.

That article is the typical gun rag article. Some info, some truth, some facts, some left out reality.

For instance, “The downside to these loads is increased recoil and additional muzzle flash.”

There are other downsides...increased chamber pressure, accelerated wear and tear, increased bolt thrust, changes to dwell time, increased slide acceleration, delayed slide action in some guns, and premature slide opening in other...I’m sure there are other issues.

Proof rounds are the rounds used in a “proof house” to check a barrel. Basically, it’s an explosive charge set off in the barrel to make sure the barrel remains a barrel and doesn’t bulge or become shrapnel.

Problem is....they do it once. Approaching proof round pressure repeatedly using +P+ ammo is absolutely going to induce metal fatigue beyond the cohesion ability of the material at some point, and that point in time will be sooner rather than later, and the results can be rather exciting, if not deadly.

The real question a guy needs to answer is this. What are you looking for when you add pressure? More velocity is usually the answer to that.
So....why more velocity? The answer in a handgun would be, usually, more penetration.

So...are there other ways to get velocity? Are there other ways to increase penetration?

The answer to both of those is yes, you don’t need to crank up pressure to +P or higher levels to get more velocity or penetration. You can get the same thing by changing bullet weight and bullet construction.

The +P is usually used to get heavier bullets to go faster...which will increase penetration, assuming the JHP bullet expands properly and doesn’t fragment. An FMJ will do the same, as you saw on the Demo Ranch video. But now you’re looking at over penetration, which is bad in several ways.

So...it’s Ok to carefully play with the overpressure ammo. But don’t think it’s the bestest or only way to do what needs to be done, there may be other better ways to achieve what you want.

 

[TNTRAILERTRASH]

Over penetration can happen with 147 grain 9mm too. I like the Hornady 124 XTP +P. It used to be cheap. It works good in 4" and smaller barrels. Good for my Glock 26, and 19. There is 115+P out there too. Premium 9mm +P+ Ammo For Sale - 127 Grain JHP Ammunition in Stock by Winchester Ranger T-Series - 50 Rounds

Your obsession with +P is probably a waste of time. 147 is slower, sometimes doesn't open up when going through heavy clothing. A couple of years ago there was a story about NYC cops shooting a bad guy and his Carhart jacket stopped the 147gr bullets. It stopped them alright. Coming out the guy's torso and stopped in back! It might have been +P(?)

There is no ultimate round. Next you'll be splitting hairs over lumens, and candela of your tactical light. Try to not over think things. Training-training-and more training.

A super dooper series on 9mm JHP's is by "Shooting the Bull" on youtube. He did some great comparisons. Even did on series on .380 too.

 

[motovate]

Anyone ever fired +P+ ammo through a firearm? I cannot remember the last time I saw +P+ ammunition being sold at a gun store.

Actually I have found that there is way more ammo choice's online then @ any gun store close to where I live so I'd say that is not a surprise. I just got interested in +P & +P+ although I did look at +P .45 a time or two. About 2 years ago I bought my first 9mm - a Ruger LC9S because it was full bore 9mm and big enough to get my paws around it yet small enough to easily carry unseen it is +P but not recommended for a steady diet or it will wear out!. Last year I bought my second one as more of a house gun with lots of rounds and I could carry it if I decided to. I know the second one Canick TP9 Elite is OK for +P even though they don't or didn't at the time specify it in writing. I contacted the factory before I bought it and they told me it was just fine with +P they just didn't advertise it - that was good enough for me. I've been loading them with Hornady 115 grn Critical Defense because I like Hornady and the round is designed for "Personal Defense". Actually at the time I hadn't paid a lot of attention to 9mm loading's - being more of a "if it doesn't start with a .357 or a 4 I didn't think much of it" kind of guy. .357 as in .357 mag, 357 Sigg in a 40 S&W Glock 23, 40 S&W, 45 ACP, etc,etc. Now I know there are a lot of good 9mm loadings and I'm liking the 124 grain Hornady Critical Defense or maybe Critical Duty +P 135 grn but neither of those are easy to get - yet.

 

[motovate]

That article is the typical gun rag article. Some info, some truth, some facts, some left out reality.

For instance, “The downside to these loads is increased recoil and additional muzzle flash.”

There are other downsides...increased chamber pressure, accelerated wear and tear, increased bolt thrust, changes to dwell time, increased slide acceleration, delayed slide action in some guns, and premature slide opening in other...I’m sure there are other issues.

Proof rounds are the rounds used in a “proof house” to check a barrel. Basically, it’s an explosive charge set off in the barrel to make sure the barrel remains a barrel and doesn’t bulge or become shrapnel.

Problem is....they do it once. Approaching proof round pressure repeatedly using +P+ ammo is absolutely going to induce metal fatigue beyond the cohesion ability of the material at some point, and that point in time will be sooner rather than later, and the results can be rather exciting, if not deadly.

The real question a guy needs to answer is this. What are you looking for when you add pressure? More velocity is usually the answer to that.
So....why more velocity? The answer in a handgun would be, usually, more penetration.

So...are there other ways to get velocity? Are there other ways to increase penetration?

The answer to both of those is yes, you don’t need to crank up pressure to +P or higher levels to get more velocity or penetration. You can get the same thing by changing bullet weight and bullet construction.

The +P is usually used to get heavier bullets to go faster...which will increase penetration, assuming the JHP bullet expands properly and doesn’t fragment. An FMJ will do the same, as you saw on the Demo Ranch video. But now you’re looking at over penetration, which is bad in several ways.

So...it’s Ok to carefully play with the overpressure ammo. But don’t think it’s the bestest or only way to do what needs to be done, there may be other better ways to achieve what you want.

I agree completely- still it is interesting to look into and I'll point out the intent of the article was just +P and +P+ not what will happen when you shoot it.. I've thought about +P a little bit in the past. Came to the conclusion it would be interesting to play with a little bit but I don't want a lot of over penetration and I do want a lot of energy/ft lbs and expansion in a short distance for a defensive round. I figure if the bullet just blows right through and keeps going still with a lot of energy left is kind of wasted spending. I've shot lot's of hot .357 and 44 mag to get the thrill and the punishment. Still learning about +P and +P+ in 9mm is interesting.

I did some looking into 10 mm SAMMI. Curent SAMMI is 37,500 - which is an Average PSI - meaning some are higher and some are lower. I found where Hornady was using 38,700 as SAMMI on 10 mm - not sure if they still consider that at this time. I also found where Col. Cooper designed it for 44,000 psi to begin with - again I don't know if that still stands or has changed. At 44,000 psi the round was too hot for most people to shoot it at the time and probably now - for a lot of the reasons you just spoke to. It is just a WAG but I suspect the industry and SAMMI got together and agreed to drop the pressure to 37,500 psi and it became gospel. No arguments but that seems to be about right to me.

 

[motovate]

Over penetration can happen with 147 grain 9mm too. I like the Hornady 124 XTP +P. It used to be cheap. It works good in 4" and smaller barrels. Good for my Glock 26, and 19. There is 115+P out there too. Premium 9mm +P+ Ammo For Sale - 127 Grain JHP Ammunition in Stock by Winchester Ranger T-Series - 50 Rounds

Your obsession with +P is probably a waste of time. 147 is slower, sometimes doesn't open up when going through heavy clothing. A couple of years ago there was a story about NYC cops shooting a bad guy and his Carhart jacket stopped the 147gr bullets. It stopped them alright. Coming out the guy's torso and stopped in back! It might have been +P(?)

There is no ultimate round. Next you'll be splitting hairs over lumens, and candela of your tactical light. Try to not over think things. Training-training-and more training.

A super dooper series on 9mm JHP's is by "Shooting the Bull" on youtube. He did some great comparisons. Even did on series on .380 too.

I'll point out that interest in a subject is not Obsession. I do agree on lots of training and bullet placement is probably more effective then a big nasty bullet flying by because you flinched

 

[ajole]

Here’s the SAAMI data. That 38,700 Hornady uses is the “Maximum Probable Lot Mean.”

And here’s what the words mean.

 

[motovate]

Here’s the SAAMI data. That 38,700 Hornady uses is the “Maximum Probable Lot Mean.”


View attachment 73470

And here’s what the words mean.

View attachment 73471

Thanks Yes I saw that MPLM with the 38,700 - wasn't / not real sure yet just how much I understand there. Seems like Hornaday is choosing to use a higher pressure then SAMMI but it is an industry standard. The top page is a little bit cut off so maybe there was a bit more info on what the numbers mean. The numbers look like they are low. IE Max AVE Pressure for 9mm is 350? 350 What? Where did you get this info - from a loading manual?? If so which one?? I was sort of getting the idea based on what I've seen so far that While SAMMI is an industry standard it is based on averages of - what 10 rounds?? So if SAMMI is exceeded - some, a little bit - your gun is not going to automatically expload and mfg's are more then likely using MPLM when designing their ammo. Or something like that. Interesting stuff.

 

[lklawson]

Here’s the SAAMI data. That 38,700 Hornady uses is the “Maximum Probable Lot Mean.”
[...]
And here’s what the words mean.
[...]

You beat me too it.

Most people don't really understand statistics past the mean. I guess that's why politicians use statistics to mislead people.

Peace favor your sword,
Kirk

 

[motovate]

You beat me too it.

Most people don't really understand statistics past the mean. I guess that's why politicians use statistics to mislead people.

Peace favor your sword,
Kirk

OK so in the first chart under 9mm MAP there is a number "350". The top of the chart is cut off at least for me so I don't see what ever else is there. Is that 350 PSI ? How can the Maximum Average Pressure be 350 when it is loaded to 35,000+ PSI? Seems like a simple question??

 

[lklawson]

OK so in the first chart under 9mm MAP there is a number "350". The top of the chart is cut off at least for me so I don't see what ever else is there. Is that 350 PSI ? How can the Maximum Average Pressure be 350 when it is loaded to 35,000+ PSI? Seems like a simple question??

Multiply by 100.

Here, this article might help:

Understanding SAAMI Pressure Standards « Shooters Notes

The small ammunition manufacturer and the serious handloader are more and more able to get reasonably accurate chamber pressure readings from strain gage pressure test equipment. We show how one can relate these results to the SAAMI Pressure standards.

shootersnotes.com

Peace favor your sword,
Kirk

 

[ajole]

Thanks Yes I saw that MPLM with the 38,700 - wasn't / not real sure yet just how much I understand there. Seems like Hornaday is choosing to use a higher pressure then SAMMI but it is an industry standard. The top page is a little bit cut off so maybe there was a bit more info on what the numbers mean. The numbers look like they are low. IE Max AVE Pressure for 9mm is 350? 350 What? Where did you get this info - from a loading manual??

As Kirk said...multiply by 100. Or, just write two more zeroes at the end.

I got it from SAAMI published documents. https://saami.org/wp-content/upload...FP-and-R-Approved-2015-12-14-Posting-Copy.pdf

Pages 6 and 17.

SAAMI lists several “standards”. Out of ten rounds, the AVERAGE is called the Max Average. It’s calculated just like how you found the average in 7th grade. That is their RECOMMENDED max for commercial loaders. Basically saying “this should be absolutely safe”.

The Max PROBABLE Lot Mean, is another way to calculate a different “average”, using statistics. They calculate that, in order to say that 97.5% of a pile of ammo made to meet the Max Average will PROBABLY be under this much. But that means that 2.5% COULD be over it.

The next number is the pressure that is the statistical max of the ten rounds tested. That’s the THEORETICAL hottest round in their test. So guns should be able to handle a few of those in every mag or two, and statistically, that pressure is to be expected once in a while even if ammo is made correctly to meet the max average.

 

[ajole]

This chart shows that whole thing. For some 40,000 psi round, not 10 mm.

The AVERAGES are the tops of the curves, but in any given sample, you should get data points (rounds, in this case) that are located down on the tails of the curves, at the left and right ends. That right end value was the furthest right column on the chart I posted above. It’s saying that IF you have a real world average like the blue one, rather than the sample red one, then you “should” see some pressures out at the right edge tail.


“Standard error” is simply a calculated thing that says “given the data values we have, and the number of data points we used, we could be off by “this much”.

 

[ajole]

Another thing to note is that, the standard error goes both ways, so that is also how we get lawyer loads. If you load lower than the lower Max, but still stay under that curve to the left, you have still met the standard.

 

[histed]

DANG! @ajole - you is purdy smyrt fera edumactor/teacher type. And dis is ZACTLY why I done teached HIS-toe-ree. All 'em number thingies makes my hade hurt. Olnyest thang I knowed was how ta fand the PLAY butten on da pro-ject-tor thinger. Den, watch You-tobe. Yessir, that's teachin!

 

[ajole]

What’s sad is when the boss man tries to tell you how “standards based grading” works, and you have to tell them their math is all wonky, and the data is either meaningless, or doesn’t mean what they say.

 

[motovate]

Multiply by 100.

Here, this article might help:

Understanding SAAMI Pressure Standards « Shooters Notes

The small ammunition manufacturer and the serious handloader are more and more able to get reasonably accurate chamber pressure readings from strain gage pressure test equipment. We show how one can relate these results to the SAAMI Pressure standards.

shootersnotes.com

Peace favor your sword,
Kirk

Yes - I thought it might be something like that - it makes sense - but where on either page did you find that stated? Loys more to read.