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Old July 31, 2011, 07:43 AM   #1
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Could Someone Explain The .38 Special +P Loads Please?

I have to show my ignorance here because I bought my last pistol over 30 years ago. (I have 8) I was looking through the re-loading charts for .38 Special and noted the +P loads. For the same weight bullet (158gr.)and same powder (HP-38) the difference for a maximum .38 Special and a .38 Special +P is only .6 of a grain.
So here are my questions. Can I assume that a older .38 Special gun is not beefy enought to shoot a +P load? Do the guns that can handle a +P load say so on the pistol? When were .38 Special +P pistols started to be manufactured? Thanks...
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Old July 31, 2011, 08:25 AM   #2
Peter M. Eick
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Boy, that is a loaded question and could give you a long answer

The quick and short answer is check your manual and see if your gun is rated +p. If so then enjoy. If not, don't do it.

The long answer is much more complex. 38 special ammo today has been downgraded when compared to times gone past. Actually all 38/357 ammo has been downgraded relative to times now past. If you actually shoot some +P in a gun made for it. I use a 38/44 Heavy Duty as my test bed but any 357 magnum will do. You will find that given a 5" barrel 38+P 158's will do about say 863 fps (Winchester +P FBI load). Factory loads will do 737 fps (Winchester 158) or 757 (CBC 158) or as much as 789 (Remington 158).

So in the same gun on the same day, a +P is doing between 130 and 80 fps faster than other loads.

Now, on the same day with 158 grn reloads, 4.6 grns of Unique will give you 925 FPS, 4.2 grns of Univ clays will do 817 fps, 4.0 grns of Trailboss will do 704 fps, 3.7 grn so of AA2 will do 795 fps, and 3.5 grns of titegroup will do 827 fps.

All of those are current book max loads for different powders.

So where does that put the might +p FBI load? Nearly 100 fps less then a conventional 158 Unique load of 4.6 grns that is conventional pressure. Most older manuals limit Unique to 5.0 grns which will give you more like 1000 FPS but that is over conventional pressures.

So, if you load lasercast bullets and use there manual (current one) with 5.0 grns of Unique you get right at 1000 FPS but if you buy a box of winchester +P FBI load and shoot it the same day in the same gun you get 863 FPS.

Interesting quandary isn't it?

So my take and my take only is that over time, the SAAMI has reduced the pressures on the 357/38 class of guns resulting in a downgrade of power. Thus the older 357 Magnum is equal to the modern 357 Maximum. The older 38/44 is now equal to the modern 357 Magnum. The older 38 special is now equal (well sort of) to the modern 38+p. The older 38 S&W is equal to the modern 38 special. All rounds have been downgraded one power level in performance in my observation and opinion.

So where does that leave you?

Read your manual and do what it says you should for your gun. If it says it can do +p, then enjoy it. If not, then don't. Just recognize that most modern big manufacturer +p rounds are not that +p really. Now Corbon, double tap, buffalo bore, and others are a total different matter and someday I will test them to see how they do.
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Old July 31, 2011, 08:38 AM   #3
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Wow, Thanks Peter! Sounds like the conundrum between a Ford and a Chevy where one claims to have more rated horsepower yet shows less torque on the same chart. I will have to assume that my older J frame S&W and the S&W M&P would not be great pistols to use the +P loads. At this point I am only comfortable with pushing higher loads in my Dan Wesson .357 Mag. as it is a much beefier pistol and will leave the .38 Specials in quieter loads.
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Old July 31, 2011, 11:42 AM   #4
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+P is Determined by PSI

SAAMI lists ammo by PSI & velocity. Most handloaders have no pressure testing equipment. If we follow & use the exact components listed in the loading manual, the velocity/PSI may be close. Change a component, pressure is changed. So the old method of start low on the powder charge and work up still holds true,while watching for pressure signs. A chronograph can be useful. SAAMI pressure and chamber drawings can be found here>
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Old July 31, 2011, 12:07 PM   #5
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My rule of thumb is to shoot +P's in steel K-frames or larger (or equivalent) and standard loads in J-frames. Some snubbies claim to be up to a steady diet of +P's but I will only shoot them occasionally or use for defensive carry when so rated. I don't enjoy stout loads in snubbys and suspect they don't enjoy it either. I load and shoot only target loads for practice in my 38's. If I feel the need to hit something harder I have other options.
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Last edited by TXGunNut; July 31, 2011 at 12:25 PM.
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Old July 31, 2011, 08:25 PM   #6
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If your guns are 30 years old, they are probably not +P rated. But, as stated, they might be able to handle it. I, however, would not take that risk. I had a couple of old 38 snubbies which I liked but I sold them because they were not +P rated. Not worth taking the chance.

I shoot +P 38 handloads out of my 4 inch 357. My 158 gr. hardcast bullets do 960 fps with Universal powder.
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Old July 31, 2011, 09:11 PM   #7
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"...say so on the pistol?..." Nope. It'll be on the manufacturer's site though.
A 30 year old .38 may or may not be +P rated. +P is a pressure thing. 30 years ago there were both. Not so much any more.
"...the difference for a..." It's less than that, but the pressures are higher due to the shorter OAL for like bullet weights.
Spelling and grammar count!
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Old August 1, 2011, 10:46 AM   #8
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Age has little to do with it. Pre-WWII S&W N frame .38s will handle +P loads (and much hotter) without any problems. The frame size and whether it's steel or aluminum are much more important.

TXGunNut's suggestion of +P in the K frames and standard pressure only for the J frames makes good sense.
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Old August 1, 2011, 11:11 AM   #9
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The frame size and whether it's steel or aluminum are much more important.
Don't forget the heat treatment of the metal as well
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Old August 1, 2011, 12:18 PM   #10
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My S&W 38s have the +p on them. I wouldn't recomend shooting them in anything not marked as rated for them.
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