Bryan Litz on Velocitiy Deviation

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    • #2782
      Anonymous
      Inactive

      At what distance are you tuning your loads for your rifle and are you using a chrony? According to Mr. Litz a rifle that shoots 1/4″ groups at 100 yards and has a standard deviation of 15 Fps will shoot far worse at 1000 yards that the same rifle shooting 1″ groups at 100 yards with only 5 Fps S.d. The hit percentage is over 10% higher for the 1 Moa gun vs the 1/4″ gun at 1000 yards due to vertical dispersion! His chapter on chronys makes me not trust any of they! My theory is to work your loads up at the farthest distance possible and find the load with the least vertical dispersion! Forget the chrony! Any thoughts on this?

    • #2786
      Wynne Echols
      Keymaster

      Steve, first off, where can an interested shooter read this? Esp. the chapter on chronographs. I do think that chronograghs serve a purpose but I also think that numbers as related to shooting are comparative but not absolute. Britt Jones and I have said that we were going to stack our chronys to see how close the results were, but we never have. In the example above, one would need a chrony to determine the SD. I do agree that the farther you do your load development the better because the longer distances would obviously bring in more variables.

      As for the longer distances, I read once where this guy said that groups shot at 500 yards would need to be multiplied by 4(not 2) to guess a realistic size at 1000 yards. In other words, this would suggest a 2.00 inch group at 500 would be close to 8.00 inches at 1000 yards because of the added conditions. I suppose just shoot it at 1000 yards and find out for yourself. Thanks for this Steve and I hope others will state their experiences with this. WWE

    • #2797
      Al Barr
      Participant

      Like you fellows, I enjoy reading about internal and external ballistics and the many different views held by great shooters, ballistitions and others.

      Just like when the horse trading starts: Show me the money! I believe in building the rifles the best we can, the same with ammo; then get out and shoot’em to “show me the money”. If any chronograph (mine is an Oehler 35P, which is supposedly laboratory quality) makes one a shooter; then I would be whuppin’ up on you boys instead of y’all whuppin’ me like a borrowed mule.

      Can anyone consistently load ammo that doesn’t shoot for beans at a 100 yards that consistently holds x ring at 600 yards? I want a load that “goes to sleep” about 200 yards, forgets all of my screw ups when breaking the shot, and finds the x ring every time. If you have this load; share it only with me until I can get us a copyright on our “new book”.

      The bottom line is: I’m with Steve and Wynne; get out and shoot to find the truth.

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