+P and +P+ Information

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.


"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???