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Thread: 38 special +P

  1. #1
    Member 22shtur is on a distinguished road

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    38 special +P

    Speer manual shows 148gr WC at ~950 fps NOT +P. It shows 140gr jacketed HP at 910 fps as +P. Why are jaketed bullets above 900 fps regarded as +P, and lead bullets above 900 fps NOT rated as +P ?

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    Senior Member bmcgilvray is on a distinguished road

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    It's said that jacketed bullets produce more friction as they pass through a barrel so that a powder charge builds up a greater "head of steam" in order to get them to the same velocity as a lead bullet of similar weight.

    I don't know this for certain because I have no pressure-testing equipment. Some published handgun reloading data appears to reflect this, listing slightly lower maximum powder charge weights for jacketed bullets than for lead bullets of the same weight.

    Just another good illustration of reasons to work up a handload when any component characteristic is altered in any way.
    TFlyboy likes this.

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    Supporting Member Oyeboten is on a distinguished road
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    Yes...as bmcgilvray mentions...

    The "+P" desigation is one of pressure, and not of FPS ( per given Bullet weight ) or effeciency.

    Jacketed or FMJ always need more pressure behind them to equal the velocities of Lead.

  4. #4
    Member 22shtur is on a distinguished road

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    Thanks. My trail gun is an older Police Positive. I mainly shoot 850 fps bullets with it at small game. But I am seeing cougars now, and want to carry a 950 fps bullet for that. I climb a very steep canyon loaded with game. The next day after the climb and descent, I am pretty slow moving. I am not going to get a bigger gun because after a few years I doubt I will ever be going up that canyon again. When I get too old, I'll disclose the canyon's location to a younger outdoorsman, and shoot my PP on easier ground.
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  5. #5
    Senior Member DWalt is on a distinguished road

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    If it's a .38 Special, your revolver is a Police Positive Special, not a Police Positive. You can shoot +P loads in it with no damage, assuming it is in sound condition. I wouldn't recommend it as a regular thing, but will be OK for your stated needs.

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    Supporting Member trap4570 is on a distinguished road
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    +P is as stated above - plus pressure. At one time the .38 was the standard police round and the +P was supposed to offer a bit extra for the officer faced with being outgunned. I suppose it added a margin of comfort being loaded in the service revolver for some. I don't think it offers much for a snubbie - but I could well be wrong. I would think the extra flash and recoil would be detrimental. But that is just my opinion.

  7. #7
    Senior Member bmcgilvray is on a distinguished road

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    I test fired Winchester factory 158 grain +P .38 Special ammunition in a junky looking Colt Police Positive Special from 1921, observing no obvious ill effects. The grip frame of the revolver doesn't lend itself to comfortable use with the load but it is manageable. Dire emergencies, as when all one has on hand is +P .38 Special ammunition with only a Police Positive (Special) to fire it and has a desperate need for personal defense, would be the only reasonable reason to fire such ammunition in the smaller Colt .38 Special revolver.

  8. #8
    Senior Member DWalt is on a distinguished road

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    At least regarding the .38 Special, the current +P load is essentially the same as the .38 Special loaded prior to the early 1970s when the factories lowered the peak chamber pressure limits of their loadings. This change was done for technical reasons associated with changes made in the methods by which chamber pressure was measured, piezo gauge vs. the earlier CUP method. Piezo gauge measurements are not comparable to CUP measurements, and in fact they measure completely different things in completely different ways. There is a lot more explanation of this involved than can be simply discussed, but the bottom line is that guns which used standard .38 Special ammunition in the 1920s can shoot +P loads safely today. But today's standard loads will put somewhat less wear and tear on a revolver than +P loads will.

    Also note that most factories keep cartridge chamber pressures somewhat lower than SAAMI-established maximum pressure limits to be safe, as different guns will produce different peak pressures, and may be inconsistent with the results obtained from the standard pressure guns used at the factories.


 

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