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I'm not sure if I trust my scale.

Discussion in 'Handloading and Reloading' started by flip180, Nov 13, 2005.

  1. flip180

    flip180 Well-Known Member

    I took out my S&W M520 with some reloaded .357's that I whipped up. I'm using Winchester brass and small pistol primers, 4.8 gr. of titegroup topped off with Hunter's Supply 158 gr. LSWC's. I'm using a lee manual and a lee scale to measure the powder charge. The load data for Titegroup and a 158 gr. lead bullet calls for;

    4.5 gr. @ 1028 fps.
    5.0 gr. @ 1108 fps.

    My Pro-Digital chrony with a ten shot string ten feet from the muzzel was reading;

    Hi=918 fps. Lo=894 fps. Avg=905 fps. Es=24 fps. Sd=6 fps.

    Something's not adding up. I would think I should be getting higher velocities with this charge. So, it must be either be the chrony or the scale. I tend to think it is more the scale. After shooting, the cases pretty much fall out of the cylinder when open and turned up side down which this isn't some thing I really don't remember seeing when shooting factory .357 magnum loads. Those usually take a good pop on the ejector rod to get them to start comming out of the cylinder. Any sugestions? Hodgdon's website calls for using Magnum primer's for this powder even though it doesn't list a specific load for 158 gr. LSWC's. My lee manual suggest using standard primer's unless specifically listed otherwise. There is nowhere in the .357 magnum load tables in my manual where it calls for magnum primers. I'm using a heavy crimp and am seeing a good amount of sooty residue of the gun after firing that almost reminds me of shooting my black powder revolvers. Any suggestions would be appreciated.

    Thanks, Flip.
  2. bogie

    bogie Well-Known Member

    1) Lawyers write the books

    2) Guns are all different

    This just means that you may wanna try a little stiffer load. Doesn't mean your scale's off.
  3. flip180

    flip180 Well-Known Member

    It just seems to me that my velocity should be at least over 1028 fps using a charge that is the the middle of the min-max allowable charge.

  4. wrangler5

    wrangler5 Well-Known Member

    What did the loading manual show for the gun/barrel used to record the data? A longer barrel or a (sealed) test barrel probably would produce higher velocities with the same loads than your gun. There might be SOME difference in the alloy used in the bullets which might produce a different velocity.

    Plus, like bogie said, guns are all different.

    FWIW, I rarely achieve the velocities predicted by the manuals using my guns and measuring with my chrony. Oh, well.

    If your cases are falling out of the cylinders then you're not near the pressure limits, and could safely start to work up heavier loads. But if the loads you have are comfortable to shoot and are accurate, consider whether you need any more speed, especially for a lead wadcutter.
  5. Jim Watson

    Jim Watson Well-Known Member

    Your scales are fine.
    Your chronograph is fine.

    Your data is incomplete.
    Your expectations are unrealistic.


    The Lee manual just reprints powder company data in abbreviated form without information as to what gun was used. The actual Hodgdon manual shows that they used a 10" barrel. Probably a Pressure and Velocity barrel in a Universal Receiver. Minimum chamber, minimum bore, unworn surface, and no cylinder gap all add up to higher velocity than a real revolver will get.

    Your velocities in your S&W are about what you should expect.

    If you want higher velocity, go to a slower burning powder, don't push a target load powder to magnum levels. Too much opportunity for a double charge, a gun was blown up at my club with what was probably a double dose of Bullseye in a .357.
  6. danhei

    danhei Member

    Here's some real world compared to powder co. data.

    Trail Boss: 4.2 gr, 158 gr SWC
    IMR's 10" test barrel barrel = 865 fps
    My OM Blackhawk 6.5" barrel = 732 fps

    Lil Gun: 18.0 gr, 158 gr Hornady XTP
    Hodgdon's 10" test barrel = 1577 fps
    My OM Blackhawk 6.5" barrel = 1412 fps

    Don't expect to get the same results as their test barrels with a revolver with a shorter barrel and a barrel-cylinder gap.
  7. Bronson7

    Bronson7 Well-Known Member

    Well, this is my take on it. Anyone weighing charges should have a set of check weights. I bought a Lee scale a few years ago and for me it was difficult to use and worse, inconsistant, which I found out by using (you guessed it) check weights. Some folks like it. I don't. Get a set of check weights and remove or confirm your suspicions.
  8. dracphelan

    dracphelan Well-Known Member

    I recently started reloading. And, I have also found that I don't like the Lee scale. I think I will go ahead and buy an electronic scale with the check weights. The Lee scale to easily goes out of zero, for my taste.
  9. Thirties

    Thirties Well-Known Member

    If you are bothered by the Lee scale going out of zero, you will be really upset with a digital scale going out of zero even more often.

    Take a look at a Redding beam scale, or the RCBS.

    Digital scales are not suited to measuring powder for handloading in my humble opinion.
  10. jdkelly

    jdkelly Well-Known Member

    Pick any scale you want, but get the check weights!


  11. 8ring

    8ring Well-Known Member

    Pick up some check weights at your local scientific supply store. My set cost less than $10. 500 milligrams equals 7.71 grains. I set the zero with no weight in the pan and then perform a second check at 7.7 gr using the 500mg check weight. Always works on my Dillon scale.

    The velocities with Titegroup are not that far off for a short barrel revolver. It took 5.2 to 5.3gr. Titegroup to get 1075 fps with a 158gr. lead bullet in my GP-100 with a 6" barrel.

  12. Sam Adams

    Sam Adams Well-Known Member

    +1. You are dealing with a potentially very serious problem if you don't trust your scale - and since you aren't weighing yourself, where an error of a few percent isn't a big deal, but instead with the charge for ammo that will be set off near your eyes and skull, don't trust ANY scale. Check it regularly, whether it is at the start, middle and end of each session, every 25 or 50 charges, or whatever - check the scale's accuracy.

    Reloading is about saving bucks while finding the best load for your guns. However, Rule #1 is to be careful and methodical so as to avoid accidents.
  13. redneck2

    redneck2 Well-Known Member

    Guess maybe I'm just really lucky, but my Pact electronic holds zero really well. I can have it shut off for a week or two and it's still accurate. I always recalibrate, but probably wouldn't have to.

    Wouldn't trade it for a dozen balance beams. It's fast, easy, and accurate.
  14. 45Frank

    45Frank Well-Known Member

    I've been using a Lyman LE1000 for 10 years now and check it and calibrate reg. and never had a problem yet. Also use an old plastic lee powder measurer. I did find that the secret is to let the scale warm up to room temp. My gun room is in my barn so.
    Good Luck

  15. flip180

    flip180 Well-Known Member

    I pulled out my other Lee scale that I got with my aniversery kit and compaired charges with the lee scale that I had been using. I'm getting about the same measurements with the same charge with in 0.1 grain between the two scales. I guess I'll go with that. I went ahead and loaded up 300 rounds last night with 4.7-4.8 grains depending on what scale I used. My powder charger is pretty consistent being as though I have a 24 fps extreame spread also.

    Thanks, Flip
  16. ID_shooting

    ID_shooting Well-Known Member

    If you get a new scale, get a good one. I started with a bottom line RCBS scale and had velocities all over the map. I knucled under and bought a spendy dillon scale, now my MV is +-15 fps on most loads. BTW, I agree on the check wieghts as well.

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