How to educated guess pressure?

Discussion in 'Reloading' started by themighty9mm, Sep 6, 2013.

  1. I guess my problem with QuickLoad is "Who says so?". For all the data that is presented have there been ANY actual calibration measurements? Where did the equations come from? Where did the powder burn rate info come from? Where did the science come from? Who says so?

    I'm neither for nor against QuickLoad. It's kind of expensive and I still don't know "Who says so?". Despite all the money I spend on shooting, I just can't justify this expense. For me...

    We have to assume that reloading manuals are providing safe data. Some manuals are clearly safer than others. Those manuals that have been scrubbed by lawyers seem to have the lower MAX loads but I might feel comfortable using any published data as long as I worked up slowly. Tens of thousands of reloaders use these manuals every day and most of them do so safely.

    So, I decided to go with Sierra for rifle loads. My pistol loads are middle of the road and just about any manual will do. Of course, my rifle loads are just middlin' velocity as well.

    I don't see the need to get anywhere near MAX. For me... Others may have a need for higher velocities but my suggestion would be to just change powder.


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    #21 F106 Fan, Sep 8, 2013
    Last edited: Sep 8, 2013
  2. I would not listen to "Speer" or "Lyman" or anyone but Accurate Powders when it comes to 2230.

    Like I said earlier, 2230 has changed in the past few years and most all data is obsolete except for Accurate/Ramshot/Western Powders.


  3. I can't answer your questions about QL as to how it works or why it works or "Who says". I can tell you that is is a very complex computer program with the guts and the workings well beyond anything either one of us know anything about or ever will.
    It's kinda like asking NASA, "Who Says" when it comes to their mathematical and computer generated solutions for space travel. We watch it and we see it, but the average Joe will never understand it.

    As for your decision to "go with Sierra" data for your rifle loads, Why?
    Sierra does not list actual tested pressures like the powder manufacturer's and Lyman does. Why is that? Answer, they do not know what the actual pressure of the tested loads is or was.
    Sierra does not have or use pressure testing equipment, they guess just like you and I do with fallible and inaccurate techniques. Techniques like CHE and PRE, reading primers, chrony data and all the other "shoot-em and Look for signs" techniques. Of all the data available, I trust Sierra the least. As a matter of fact, if I had to choose between QL and Sierra, I would go with QL hands down evey time.
  4. Where exp comes in. When I am going to a new bullet/powder or calibner combo, I use avg book data & work up. Using a chrono, comparing vel to book data, modififed for bbl length of course, it's a safe way to work up loads w/ no guessing involved. Like data manuals, LQ is another good tool, but not to be trusted as the final word.
    #24 fredj338, Sep 8, 2013
    Last edited: Sep 8, 2013
  5. Velocity "Modified for barrel length", How much for each inch of barrel? Is this the same for rifle as it is for pistol. Where did you get your "Modified for barrel length" number? Is there a hard and fast rule for this or is it an educated Guess?
  6. There are few hard & fast rules in reloading. For rifles, 40-50fps is the avg vel loss per 1" of bbl. Yeah, it's based on various tests through out the year, but it is a guide line. For handguns 30-40fps +/-, again, based on past tests. My point, you can't look at book data for say the 223 w/ 24" bbl & try to get sim results w/ a 16" bbl AR or 44mag loads in a 4" from 7 1/2" data. None of this is new, w/ QL just being a better WAG. The only true numbers come from a chrono & pressure test in your gun. Even pressure tested data in the books is good for ONLY that gun & those exact components.:dunno:
    #26 fredj338, Sep 9, 2013
    Last edited: Sep 9, 2013
  7. Right, so following published data is pretty much a WAG as is Quickload.
  8. delete double post
    #28 steve4102, Sep 9, 2013
    Last edited: Sep 9, 2013
  9. Both are educated WAG. QL, no gun, no actual testing, just average numbers. In a manual loads are tested in a single gun. So your results will vary, sometimes quite a lot. The only way to accurately work up loads is in your gun, chrono & pressure testing. Since none of us do that, we have some extrapolating to do, but you can never, with finality, say what the pressure is in your load/gun combo.:dunno:

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