INTRODUCTION
I spent some time last night building .270 bullets using hogdgen 4831 powder and a couple of different bullets, 130grain Boat tail spire point (BTSP) Nosler Partiion and some 90 grain Jacketed Hollow Point (JHP)Sierra Varminter.
MATERIALS AND METHODS
I began by reading in the lyman book for reference starting and maximum loads. Then I loaded four each of the 130 gr BTSP with 54 56 and 58 grains of powder while four each of the 90 grain JHP projectiles would be propelled by either 56 or 58 grains of H4831.
I followed the advice of chris on bullet seating and I adjusted the bullet seating such that when chambered a black sooty bullet would just barely come back without any marks.
I went for lunch today and shot all four of each loading with one exception where I had only three cartidges.
RESULTS AND DISCUSSION
My worst groups were those designated as starting loads with groups just over two inches and the best I managed was a three shot group of 26mm, just a hair over an inch. I resisted the temptation to run real statistical ananlysis like SAS or SPSS on the grouping data only because of the low sample size and lack of chronographic data. I still felt the need to calculate mean and standard deviation of bullet distances for each of the loads. My best load (90gr JHP with 58 grains of Powder) had an average distance between any two shots of 19.3mm and a standard deviation of 14mm.
FUTURE RESEARCH
While not earth shatteringly good I am pleased with not being blown up and furthermore I am pleased with the accuracy from this intial run and look forward to fine tuning where I will shoot more bullets per loading yielding greater sample size, better calculations of true standard deviation and opening the door to Analysis of variation to find combinations which result in significantly better accuracy.
I spent some time last night building .270 bullets using hogdgen 4831 powder and a couple of different bullets, 130grain Boat tail spire point (BTSP) Nosler Partiion and some 90 grain Jacketed Hollow Point (JHP)Sierra Varminter.
MATERIALS AND METHODS
I began by reading in the lyman book for reference starting and maximum loads. Then I loaded four each of the 130 gr BTSP with 54 56 and 58 grains of powder while four each of the 90 grain JHP projectiles would be propelled by either 56 or 58 grains of H4831.
I followed the advice of chris on bullet seating and I adjusted the bullet seating such that when chambered a black sooty bullet would just barely come back without any marks.
I went for lunch today and shot all four of each loading with one exception where I had only three cartidges.
RESULTS AND DISCUSSION
My worst groups were those designated as starting loads with groups just over two inches and the best I managed was a three shot group of 26mm, just a hair over an inch. I resisted the temptation to run real statistical ananlysis like SAS or SPSS on the grouping data only because of the low sample size and lack of chronographic data. I still felt the need to calculate mean and standard deviation of bullet distances for each of the loads. My best load (90gr JHP with 58 grains of Powder) had an average distance between any two shots of 19.3mm and a standard deviation of 14mm.
FUTURE RESEARCH
While not earth shatteringly good I am pleased with not being blown up and furthermore I am pleased with the accuracy from this intial run and look forward to fine tuning where I will shoot more bullets per loading yielding greater sample size, better calculations of true standard deviation and opening the door to Analysis of variation to find combinations which result in significantly better accuracy.
posted by steven-hoffman | 6:15 PM
3 Comments:
THE SCIENTIFIC REPORTING HERE STEVE IS A NICE TOUCH, BUT IT MAKES ME THINK THAT THERE IS NOT NEARLY ENOUGH ALCOHOL IN YOUR SYSTEM TO REALLY ATTAIN GOOD DATA AT THE RANGE. YOU SEE STEVE, ALCOHOL RELAXES THE SENSES AND MUSCLES THAT ARE IMPORTANT TO SHOOTING GREAT GROUPS. THE TRIGGER FINGER BECOME ONE WITH THE RIFLE, AND THE BRAIN STARTS REALLY FOCASING IN ON THAT TINY SPOT THAT PRODUCES .122 GROUPS. YOU SHOULD TRY IT, AND WHEN YOU DO YOU WILL THANK ME FOR CHANGING YOUR LIFE. HAPPY SHOOTING
CHRIS COME ON NOW IM NOT SAYIN IVE PRODUCED A .122 YET CAUSE I HAVENT, IT JUST SOUNDED LIKE A GOOD NUMBER TO STRIVE FOR. THE BEST IVE SHOT SO FAR IS THE .212 WITH THE 300 AND IMR 3031 A WHILE BACK. I HAVE A COUPLE OF 22-250 TARGETS AT THE HOUSE THAT MIGHT GET CLOSE TO THAT BUT I HAVE TO LAY THE CALIPERS ON EM TO SEE. I KNOW YOU SHOT THE .137 HERE LATELY AND I KNOW THAT BEER AND/OR WHISKEY WAS PRESENT. THIS BRINGS ME TO MY ORIGINAL POINT, BEING THAT I HAVE OBSERVED SMALLER GROUPS WHEN THE NERVES ARE "WIGGLED"
Was I supposed to shoot the groups at 100 yards?
I was at 150-175, since that is about the farthest I typically have call to shoot.
I figured practice like you intend to play.
In regard to the wiggling of nerves I will just have to do better next time.
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