I picked up some 9mm +P ammo at the range, headstamp "WIN NT 9MM +P". Im curious if it the load that makes it a +P or if it is the case. In other words, if I load a +P case with the same charge as a non +P, will I have the same velocities?
+P ammo
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Re: +P ammo
9mm +P brass is usually something that's stamped by Winchester, I can't think of ever seeing Speer, Remington, Federal or any of the other major players stamping "+P" on their cases beyond Winchester.
I have quite a few of the 9mm +P and 38Spc +P cases. I chopped one of each down the centerline and there was no meaningful difference between them and the regular 9mm and 38 cases.
The powder charge difference and sometimes bullet weight difference is what discerns a +P load, the brass reloads just fine and I've never treated it any differently.
ETA: The +P that Winchester stamps on the cases is marketing fluff, that's all I'm getting at.
9mm +P brass is usually something that's stamped by Winchester, I can't think of ever seeing Speer, Remington, Federal or any of the other major players stamping "+P" on their cases beyond Winchester.
I have quite a few of the 9mm +P and 38Spc +P cases. I chopped one of each down the centerline and there was no meaningful difference between them and the regular 9mm and 38 cases.
The powder charge difference and sometimes bullet weight difference is what discerns a +P load, the brass reloads just fine and I've never treated it any differently.
ETA: The +P that Winchester stamps on the cases is marketing fluff, that's all I'm getting at.
Re: +P ammo
My first time loading for an old Rossi 38 Special, I loaded some +P loads, and that gun didn't like them at all. Then I found out it wasn't rated for +P ammo, so I fed it plain 38's.
My first time loading for an old Rossi 38 Special, I loaded some +P loads, and that gun didn't like them at all. Then I found out it wasn't rated for +P ammo, so I fed it plain 38's.
Re: +P ammo
9mm, 38 Special, and 45 ACP were "invented" before we had modern steels. Through modern metallurgy, we can boost chamber pressures to increase performance in the original "volume" case. Most modern 9/38/45 handguns will handle the higher pressure "+P" loadings, while the older firearms may not (or newer firearms not designed to withstand "+P" loads). Brass for +P loads are headstamped accordingly so they can be identified as higher pressure and not to be loaded in firearms not rated for such. As far as I know, there is no difference in the brass case, just the powder charge ("regular" brass can be loaded to +P pressures with no ill effects).
You will not see "+P" 40 S&W or 357 Sig, for example, because these rounds were originally designed for the higher pressure loads.
"+P" ammunition has SAAMI pressure limits established. Beware of any load designated as "+P+", as there is NO established industry pressure standard for such (could be a bomb waiting to explode in your hand).
Short answer, it's not the case that makes it +P....
Cheers,
Bill
(Edited to add) I chrono'd a bunch of different 9mm ammo when I first got my M&P9 (Owner's manual said it was rated for "+P" loads, and inculded the above warning about "+P+"). Most of it produced between 300-325 ft-lbs of energy. Double-Tap ammo 124 gn +P load produced 410 ft-lbs of energy (and was headstamped +P), which is in the light 357 Magnum territory (compares to the 357Mag 110JHP loading). I don't feel undergunned carrying the 9mm with that Double-tap +P load....
9mm, 38 Special, and 45 ACP were "invented" before we had modern steels. Through modern metallurgy, we can boost chamber pressures to increase performance in the original "volume" case. Most modern 9/38/45 handguns will handle the higher pressure "+P" loadings, while the older firearms may not (or newer firearms not designed to withstand "+P" loads). Brass for +P loads are headstamped accordingly so they can be identified as higher pressure and not to be loaded in firearms not rated for such. As far as I know, there is no difference in the brass case, just the powder charge ("regular" brass can be loaded to +P pressures with no ill effects).
You will not see "+P" 40 S&W or 357 Sig, for example, because these rounds were originally designed for the higher pressure loads.
"+P" ammunition has SAAMI pressure limits established. Beware of any load designated as "+P+", as there is NO established industry pressure standard for such (could be a bomb waiting to explode in your hand).
Short answer, it's not the case that makes it +P....
Cheers,
Bill
(Edited to add) I chrono'd a bunch of different 9mm ammo when I first got my M&P9 (Owner's manual said it was rated for "+P" loads, and inculded the above warning about "+P+"). Most of it produced between 300-325 ft-lbs of energy. Double-Tap ammo 124 gn +P load produced 410 ft-lbs of energy (and was headstamped +P), which is in the light 357 Magnum territory (compares to the 357Mag 110JHP loading). I don't feel undergunned carrying the 9mm with that Double-tap +P load....
Re: +P ammo
Something to keep in mind, most alloy frame pistols aren't designed for a high volume diet of higher pressure ammo. They can be damaged if they get shot a lot with hot loads.
Something to keep in mind, most alloy frame pistols aren't designed for a high volume diet of higher pressure ammo. They can be damaged if they get shot a lot with hot loads.
Re: +P ammo
For what it is worth...I have a couple of boxes of "Double Tap" 10mm 135 grain ammo. The box says, "1600 fps". Chronos at 1650 fps. That is, in my book, a "double tap" in a single load. In short...it does as advertised.
For what it is worth...I have a couple of boxes of "Double Tap" 10mm 135 grain ammo. The box says, "1600 fps". Chronos at 1650 fps. That is, in my book, a "double tap" in a single load. In short...it does as advertised.
