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Thread: .357 140 grain xtp data

  1. #1
    The Nostomaniac 03RN's Avatar
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    .357 140 grain xtp data

    I just picked up some 140 xtps for my m66. Ive found data with unique up to 9 grains but aliant lists 8gr as max which seems light. I loaded a few up to 8gr to just be prudent. Aliant lists 8grains at 1185 and am just wondering what you'll have gotten.

    I need to get some more 2400 but wanted to try unique. I figure the 140 is good middle ground for my 2.75" barrel.

    Sierra lists 9gr as max at 1250 and 1500 out of a rifle. Not a barn burner but im thinking that would be a good load from coyotes up to deer.

    I know you can get more velocity with a slower burning powder but i think the 140gr xtp is perfect for 1250-1500fps.

    If 8 doesn't show any pressure signs ill work up a bit i guess.

  2. #2
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    Hornady's 7th Edition shows 1350 fps from their max load of 2400 with that bullet...from an 8" Python. Your 66's barrel is five inches shorter, and the rule of thumb is that you lose 25-50 fps per inch, and Unique can't push a bullet as fast as 2400 at max pressure. My guess is that you'd get about 1100-1150 fps from your gun using Unique. It still beats a sharp stick. Just be aware that you're not going to match book velocity with a short barrel.

  3. #3
    The Nostomaniac 03RN's Avatar
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    Quote Originally Posted by revchuck38 View Post
    Hornady's 7th Edition shows 1350 fps from their max load of 2400 with that bullet...from an 8" Python. Your 66's barrel is five inches shorter, and the rule of thumb is that you lose 25-50 fps per inch, and Unique can't push a bullet as fast as 2400 at max pressure. My guess is that you'd get about 1100-1150 fps from your gun using Unique. It still beats a sharp stick. Just be aware that you're not going to match book velocity with a short barrel.
    Oh of course. Im takeing that into account. The 140s seem to have a very wide velocity range.

    Id be more than happy with 1150 from the 66.

  4. #4
    Site Supporter OlongJohnson's Avatar
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    Quote Originally Posted by revchuck38 View Post
    Hornady's 7th Edition shows 1350 fps from their max load of 2400 with that bullet...from an 8" Python.
    If you look at ballisticsbytheinch "real world" data, Colt revolver barrels are disproportionately slow. My understanding is that is due to tapering toward the muzzle. Good for accuracy, but puts more drag on the bullet as it swages down.

    I've seen more than a handful of reports from people saying the 140 XTP is their most accurate load, but they may have been GP100 shooters.
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  5. #5
    Quote Originally Posted by 03RN View Post
    Oh of course. Im takeing that into account. The 140s seem to have a very wide velocity range.

    Id be more than happy with 1150 from the 66.
    Out of my 2.75" 66-1 I get 1250 with 158 XTPs and it's at the starting charge weight!

    I don't use Unique though. I use VV N-110. It's the best full house magnum powder I've ever used. Less flash and blast with the "screaming missile" loads. If you are going to buy another powder grab a pound of that and break out your chrono, you'll probably be as shocked as I was.

    And timely thread, I happen to have 2 boxes of 140 XTPs on my bench as I type this. I really need a .357 lever gun... I have a .375 so why not?
    Last edited by Spartan1980; 12-26-2019 at 11:42 PM.

  6. #6
    The Hornady 10th does not list Unique and the 140 XTP.

    The Lyman 50th shows the 140 with 8.9gr of Unique at 1,233 fps from a 4" barrel.

    Here's some Speer data using a 135 GDHP:



    Last edited by Tokarev; 12-27-2019 at 05:20 AM.

  7. #7
    The Nostomaniac 03RN's Avatar
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    8 grains under the 140xtp felt like a .38 special. Especially fired back to back with remington 125 grain sjhp at 1450.

    Guess ill work up to 9gr that sierra posts as max

  8. #8
    The Nostomaniac 03RN's Avatar
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    Im only sticking with unique right now because i have an 8lbs jug. Ill experiment with others when i get some new powders.
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  9. #9
    Quote Originally Posted by 03RN View Post
    Im only sticking with unique right now because i have an 8lbs jug.
    That's alotta Unique if you are not loading shotguns.


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    Last edited by mmc45414; 12-27-2019 at 06:30 PM.

  10. #10
    Lymans Second Edition "Handgun & Pistol Handbook" lists 8.9 gr/Unique as a max load for 140 gr 357 mag, so you're in the right ballpark. 1233 fps from a 4 inch pressure barrel at 40,000 CUP.

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