Sierra Load data--How Conservative is it?

MarinePMI

MarinePMI

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    • Jun 3, 2010
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    #1
    All,

    I've been noodling through some Sierra load data for the Valkyrie, and had a question: How conservative is the load data they list?

    Hodgdon data and Hornady are notorious for being super conservative (to the point of almost being dangerous; in that people disregard the max loads because they are so conservative).

    I'm kind of curious if folks have found the published Sierra data to be accurate (both in velocity and max pressure).

    Thanks for any responses...
     
    Last edited:
    #3
    go up in .3 grain increments until you hit pressure. back off a little

    load data is very conservative. and often below factory ammo

    padom is pushing 88s around 2800. check his thread
     
    #4
    Sierra data is not conservative. It is accurate to the firearm and components used in their testing. Your firearm and components may differ, allowing you to exceed their max charge weight.

    But you know this already.
     
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    #5
    918v said:
    Sierra data is not conservative. It is accurate to the firearm and components used in their testing. Your firearm and components may differ, allowing you to exceed their max charge weight.

    But you know this already.
    Click to expand...


    Correct. Just checking to see if there was a gross conservative error/bias in their data like Hodgdon or Hornady.
     
    #10
    Based on the last 10 years of using Sierra, Hornady, Lee, Lyman, Nosler, and Barnes books I got.... And spatterings from the Interwebs..... Sierra seems to be the most "accurate" in relation to their stated max loads when using Sierra projo's like said above.
     
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    #11
    clcustom1911 said:
    Based on the last 10 years of using Sierra, Hornady, Lee, Lyman, Nosler, and Barnes books I got.... And spatterings from the Interwebs..... Sierra seems to be the most "accurate" in relation to their stated max loads when using Sierra projo's like said above.
    Click to expand...

    Thanks for the additional confirmation. I must be the odd ball, but for some reason, over the last 30+ years of reloading, I never loaded Sierra bullets that much. So, I never really relied much on their load data.
     
    #12
    Sierra load data for 270 win is right on for me. There max of 55 grains of IMR 4350 with 130 grainers is working well.

    Another good source in my opinion is Lyman manuals.

    Either one of these two will get closer to a realistic max charge weight than any of the others that I use.
     
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    #13
    Yeah, I have a Lyman manual, and as you say, it has been pretty reliable. The issue is that some of these new bullets/cases just haven't made it into the manuals yet (like the .224 Valkyrie for example). So, we're left to what is currently being published as soft copy updates, and here lately, it seems much of the data is overly conservative. So conservative in fact, that I'd argue it's almost equally dangerous as internet derived load data, as people just assume it's conservative.

    I know a few years back (when Hodgdon, Alliant and IMR all merged) there was a big issue with the load data, and the parent company was in the process of retesting much of it. This was due to different methodologies (historically) being used by the different companies (CUP vs. PSI, test barrel lengths, etc.). Needless to say, there were only two types of pressure guns being built in the US at the time (probably still is the case), so they (Universal receiver pressure guns) were backordered for a while. I was (at the time) in the process of helping a manufacturer stand up a ballistics lab, and so in doing so, was made aware of the goings on at Hodgdon/IMR/Alliant (re: retesting/publishing of load data, so that it all aligned to the same testing process). Subsequently, that's when all this BS, overly conservative load data came out, causing more harm (IMHO) than good. I mean, what's the use of overly conservative data (faulty), when all is does is muddy the waters of where that limit is?

    At any rate, I digress... Too early, and not enough coffee this morning...
     
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    #14
    Published load data is tested to be within SAMMI specifications for the cartridges, that is all. In most every case, the bullets are seated to what the bullet manufacture recommends.
    No hidden secrets or vodoo going on with these companies.
    Start at the suggested starting load and work up until you find "your load" or you start to see pressure signs. Your rifle with your components will be the determining factors..
     
    #15
    Engine 22 said:
    Published load data is tested to be within SAMMI specifications for the cartridges, that is all. In most every case, the bullets are seated to what the bullet manufacture recommends.
    No hidden secrets or vodoo going on with these companies.
    Start at the suggested starting load and work up until you find "your load" or you start to see pressure signs. Your rifle with your components will be the determining factors..
    Click to expand...

    Agreed, and with SAAMI spec'ed chambers. Which should have the max load data somewhere near the max of what most find with their rifles/pistols.

    You prove my point, there is no voodoo here, and yet the Hornady and Hodgdon data has been shown to be waaaaayyyyy conservative. Much more than realistic variations in chambers and ammo manufacturers are. And therein lies the rub. If the listed data is so conservative that reloaders basically start with the max load and work up, than the data is bullshit, and it's usefulness is questionable. Load data is supposed to show min and max loads; not data that is purposely gelded and is no where near max load in a SAAMI spec chamber.
     
    #16
    Hornady’s data has to consider all the various “match” chamber configurations as well as all the different brass out there. Short tight chamber plus a heavy case equals more pressure than a loose chamber with a light case.

    The 224v is a semi auto round which poses two kinds of pressure problems: the basic kind and the gas system kind. You might have a safe bolt gun load that wreaks havoc on the gas system and cases eject looking like they were subjected to 100,000PSI.
     
    #17
    MarinePMI said:
    Agreed, and with SAAMI spec'ed chambers. Which should have the max load data somewhere near the max of what most find with their rifles/pistols.

    You prove my point, there is no voodoo here, and yet the Hornady and Hodgdon data has been shown to be waaaaayyyyy conservative. Much more than realistic variations in chambers and ammo manufacturers are. And therein lies the rub. If the listed data is so conservative that reloaders basically start with the max load and work up, than the data is bullshit, and it's usefulness is questionable. Load data is supposed to show min and max loads; not data that is purposely gelded and is no where near max load in a SAAMI spec chamber.
    Click to expand...

    No, my point is simply that the data isn't established with yours, mine, or the next guys firearm and components. The data is established to be within SAMMI spec for the cartridges- taking into account what pressures the cartridges are designed to operate at safely given the worst case scenarios for chamber dimensions, components, barrels, metallurgy, etc., etc.,.... and to provide a base-line of data for the reloader to work with their firearm and components.
    Which reloading manual suggests starting load work up at max charges?
     
    #18
    Engine 22 said:
    No, my point is simply that the data isn't established with yours, mine, or the next guys firearm and components. The data is established to be within SAMMI spec for the cartridges- taking into account what pressures the cartridges are designed to operate at safely given the worst case scenarios for chamber dimensions, components, barrels, metallurgy, etc., etc.,.... and to provide a base-line of data for the reloader to work with their firearm and components.
    Which reloading manual suggests starting load work up at max charges?
    Click to expand...

    None. But when the data is consistently overly conservative across the spectrum, that's what you get (people using max loads as a starting point). And that's why I contend that overly conservative loading data is just as (if not more so) dangerous than optimistic load data. If you have a SAAMI spec chamber, list the brass, the primer and the bullet used in developing the load data, the max load should actually be very close, not complete whole grains of weight off, which is the case with Hodgdon and Hornady data across all their data (or at least the 20 or cases I have reloaded for).

    The manufacturer caveat of "always start low and work up" becomes meaningless, and more of a liability protection, than of having any real use.

    I mean some of their data, at max load, leaves cases not even obturating fully in the chamber! WTF? That's not a slight variation in chambers, that's just plain outright overly conservative data and actually encourages ignoring their max load listings (since the max load data is obviously not even near max load). Which makes it dangerous.

    If data were account for the variations across components and chambers, then why even list what case or primer? The only variation in load data should be for slight variations in chamber dimensions. Period. In this day and age, with our level of technology, the industry can do better.
     
    #23
    918v said:
    So a conservative source of data toasted a primer pocket with a mid level charge?

    Can’t be
    Click to expand...

    I thought the consensus was that Sierra data was not conservative at all? Or is that some sarcasm slipping out? :D

    My first thought was maybe the bullet was seated long (as in, into the lands/grooves).
     
    #26
    I don't recall what my jump was but that federal brass is junk, starline is much better in the Valkyrie. Rifle +2" gas system on a 22" barrel. In fairness they would still hold primers but the primers were seating significantly looser, loose enough I tossed them after that next firing.
     
    #27
    Gentleman,

    I hate to inject this and I don’t intend to offend anyone, but without pressure testing your load in your rifle you do not know what your pressure is. If you load to the point you see pressure signs, you are well beyond the SAAMI maximum,. Back off a few tenths and you are still over and operating in the safey margin of the system.

    If you look at most data, such as Sierra or Alliant, you do not see a pressure listed but you see a maximum load that is within the SAAMI specification for the combination tested and listed. In the case of Sierra and Hornady the loads typicaly increment in 100fps so the last load listed typically is below max but the next increment is over. Alliant lists “recipes”. They do not represent pressure but warn that this is the maximum safe pressure that they recommend.

    Even where pressure is listed as Hodgdon the max load data may not be at max pressure, such as varget with 53SMK in 223. The max is based on case capacity with a compressed charge.

    So the data is conservative, in that it does not exceed the expected SAAMI pressure for the Testing system chosen (crusher CUP or transducer PSI).
     
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