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Thread: Underwood 38 Special +P 158 grain Hi-tek, how are they doing it?

  1. #1
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    Underwood 38 Special +P 158 grain Hi-tek, how are they doing it?

    How are they getting 1200+ with a 38 special and staying within SAAMI +P specs? Or are they way over pressure? They list it at 1250FPS and the chronograph is giving 1200+ out of a 4" barrel. Just over 1000 FPS is the most I have been able to find with any powder combination of published +P data.

    https://youtu.be/xVVlDcsF_s0

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  2. #2
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    There is no magic so my guess is they are overpressure. I won't shoot stuff like that in my guns, several of which aren't strong to begin with.
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    There is no reason to push a 38spl that hard. If you want that performance, buy a 357. You're not doing yourself or your gun any favors by pretending a 38 is a 357, and Underwood should probably double-check their loading. Given how mild 357 loads are today compared to yesteryear, that's darn close to full power magnum speed in a factory cartridge.
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  4. #4
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    CIP pressure for 38 special is higher than SAAMI 38+p. I would have to look it up but I think CIP is 21k PSI. Pull a round and weigh the charge. If it is around 6-6.5 grains it is likely in Unique burn range or if it is 10-12 grains it might be Accurate No. 9 to 2400 burn rate. For safe pressures I would expect to find 10-12 grains of slow powder to make those kinds of velocities.

  5. #5
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    Don't ask me how I know but you can get close with Unique. I found out that there is a big difference between 5.2 grains and 5+2 grains on the scale when you have a rectal cranial inversion. If you look around you can find the old 38-44 loads that are pretty warm.
    Last edited by nannyhammer; 09-28-2022 at 06:50 PM.

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    They use the data shown in the Speer #8 Loading Manual ...
    Or the test barrel is a Universal Receiver ... no cylinder and no cylinder gap ...
    Or they calculate using the new left math ... you know 2 +2 = 12

    The 38-44 loads listed in Elmer Keith's 1936 reloading book ...160 gr. cast SWC , 13.5 grs 2400 loaded in Remington 38/44 cases w/ Remington primers ... no velocity is listed ...
    But I bet it comes close !!!
    Remember this was 1936 and the 357 magnum hadn't been invented ... the 38/44 load was the 38 Special +P of that era and Remington loaded 38/44 factory ammo in Remington cases headstamped 38/44 ... look in the book at the photo's !
    Gary
    Last edited by gwpercle; 09-28-2022 at 07:18 PM.
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    Quote Originally Posted by gwpercle View Post
    They use the data shown in the Speer #8 Loading Manual ...
    Or the test barrel is a Universal Receiver ... no cylinder and no cylinder gap ...
    Or they calculate using the new left math ... you know 2 +2 = 12
    Well, the test by the utuber measured the MV and was getting over 1200 FPS from the 4" revolver. So it must be from the Speer #8 manual.
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  8. #8
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    IIRC the old Super vel ammo used slightly undersized projectiles to get higher velocity.
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    Quote Originally Posted by Thumbcocker View Post
    IIRC the old Super vel ammo used slightly undersized projectiles to get higher velocity.
    I would have thought that would slow it down by allowing gas to escape around it. Interesting.
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    Quickload thinks that they are running close to 25kpsi to get over 1200fps with either Blue Dot or 2400.

  11. #11
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    Quote Originally Posted by rosewood View Post
    I would have thought that would slow it down by allowing gas to escape around it. Interesting.
    Probably not that small. .355 pill down a .357 bore will still engage the rifling and seal good enough. Not sure you could detect blowby in a pistol length barrel. Now, a .425 jsp intended for the 44-40, but fired in a .430 44 mag barrel would likely leak.

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    VIRGEL shows the same Defense Wound Mass for a 35 caliber SWC bullet at a velocity of 401 to 1596 fps so if it were me I would select no more than 750 fps. Fast recovery, low muzzle blast in close quarters and just as effective.

  13. #13
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    Doesn’t moly coating yield higher velocities at the same pressure?

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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check