I am very new to the reloading world and noticed that some of the brass I was looking at on MidwayUSA website is +p and some brass is not. I,m looking to reload some for my XDM 9mm luger.

If your loading normal pressure rounds there is no need for the +P brass, the outside dimensions are the same but the +P is usually thicker in the web area of the case.
If your staying at or below max in your manuals don't worry about it.

Greg

There is no difference between standard brass and +P brass other than the headstamp itself. I got this information from the horse's mouth:Starline Brass who sells both. The +P is there only to help the reloader remember what is loaded as +P and what is not. While I have purchased some +P brass I rely more on my box labeling than the headstamp to keep things straight.

If in doubt about what I say here, just contact Starline yourself and they will tell you the same thing. Here is the statement copied and pasted directly from their website:


"9MM+P has no difference from the standard 9mm Luger other than headstamp designation for load segregation. Due to standard case design, it will handle +P pressures with no problems."

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Andy

+1 on the question I too was wondering. I figured it would be the same if not a tad "thicker" to handle higher pressure. Thought it would not harm anything to use it in my normal target loads except perhaps extend the case life..
Very informative.

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sw9ve, 24/7 pro Ds, Hs M4

The brass is not intended to contain the pressure, that is the firing chamber's job. Think of the brass as a gasket.

There are some instances where the brass cartridge case does really limit the max pressure. The old black powder balloon design .45LC is an example. Don't load those with smokeless powder to the max for .45 LC in your manual. Of course the gun is an issue to. An old 1873 Colt made for black powder isn't going to like it eiither.

A .30-40 Krag case (designed for smokeless powder from the start) can't be loaded up to .308 or .30-06 pressures). Both the gun and the brass are limiting factors. The old .30-30 has been made for smokeless powder from the start but the case design is the real limiting factor. Your old Winchester 94 is limited in pressure. But there are a few bolt guns and at least one lever gun (the Savage 99) that were made in .30-30, that can take modern high pressures, but that doesn't mean that you should pack your .30-30 brass with enough powder to approach .308 or 300 Savage performance. The cartridge design just won't take the pressure.

With the ageless .45-70 you can load modern commercial brass to a very wide range of pressures (low for Sringfield Trapdoors, Medium for Marlin 1895, and High or Ruger and TC single shots) and the the same brass is used for all classes of gun. I do have to be careful because I have several .45-70 rifles and I have to take great care not to use my Marlin loads in my 1873 Springfield Trapdoor.

The 9mm was made for pretty high pressure right from the start and so uploading it to +P pressures is not a big deal assuming that your gun is in good condition and rated for it. The notorious NATO 9mm is too hot for many handguns but the brass isn't the issue. The gun is.

A lot of guys, myself included, load .38 special cases to +P pressures and it's certainly no big deal for the brass. Of course you would want a gun rated for +P in order to do that. You could probably load .38 special to .357 mag pressures (using starting loads for that caliber) and fire it in a .357 revolver (although neither I nor anyone else is going to tell you that it's OK to do so) with out over stressing the brass.

The point is that with .38 special and 9mm there isn't anything special about brass that is stamped "+P". The brass can be a limiting factor (like the .30-30 and the .30-40 Krag) but often it is not.

Sorry, I think someone asked me what time it is and I just told them how to build watch.

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Andy

Give a man a fish...

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sw9ve, 24/7 pro Ds, Hs M4