Pressure question on max charge?

Discussion in 'Reloading' started by elmerdeer, Apr 30, 2007.

  1. elmerdeer

    elmerdeer Well-Known Member

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    Jan 21, 2007
    I was doing some load development in my 7mm mag using RL22 and 160 accubonds, I checked a few books and started at 65grs and went past max at 67grs. So my velocity at 65gr was 2843 5 shot average, 65.5 gr shot up to 2990av. could not figure out why? Any Suggestions? Next 66gr back down to 2886 av. and my group shrank to.250" shots, great!Then went a touch over max to 66.5grs and speed was 2933 and it opened up some, next went up to 67grs and my group for 3 shots went into .153" excellent again but the other 2 shots opened a bit, my error I think. I see that most everyone pushes their speed to 3050 alot of times,is it safe for me to go a little higher like to 68 grs of RL22? Have not seen any pressure signs like sticky bolt.My barrel is also 26 inches long and the gun is a Sauer202, What are your experiences with the first situation of a jump of velocity? And is velocity a safe way to gauge if your getting near max? Because book velocity does not match my numbers.
    Thank you
    Elmer
     
  2. Guest

    Guest Guest

    What are the extreme spreads and standard deveations of your loads?These will usually indicate where the balance of that load is.I have found that a slower powder will give higher velosity with out getting into pressure problems.My own 7mm mag likes H870(no longer available) but there is a powder available from Thunder bird ctg co. in Arizona that I think is the same thing.Maybe the new Hodgdon H 869 might get the same performance.My old load for reference is 79.5 gr of H870,160 gr bullet=3100 fpsin a 26"Ruger #1