joeb33050
03-27-2008, 07:56 AM
POWDER POSITION SENSITIVITY TESTING
Does the position of the powder in the cartridge case affect muzzle velocity, (MV) and/or the standard deviation, (STDEV) of MV?
I had tested the sensitivity of a powder by testing for increased accuracy with a minimum sized Dacron wad tamped down on the powder; and concluded that, for example, SR4759 and Unique are position sensitive in the 45/70 and IMR4227 is not position sensitive in the 32/40 and 30/30.
The testing conditions were expanded when I realized that my definition and test conditions were not complete (or correct); this epiphany occured after a lot of testing.
TESTING CONDITIONS
POWDER FRONT-hold the rifle with cartridge chambered at ~ a 45 degree angle down and slap the side of the rifle three times, then put it carefully on the rest.
POWDER LEVEL-put the rifle with cartridge chambered on the rest and slap the side of the rifle ten times.
POWDER REAR-hold the rifle with cartridge chambered at ~ a 45 degree or greater angle up and slap the side of the rifle three times, then put it carefully on the rest.
DACRON WAD-I recommend cotton but use Dacron wads. I use as small a wad as possible, a teased wad about dime to penny size, tamped down on top of the powder with a pencil.
I try to chronograph a minimum of 15 of each condition, shooting at 100 yards over my PACT chronograph.
Il record all results on an EXCEL workbook called "POWDER POSITION SENSITIVITY" and a WORD summary, this is it, called " POWDER POSITION SENSITIVITY TESTING". (See the EXCEL workbook for all the information about the loads and results.)
These two files will be on http://sports.groups.yahoo.com/group/CB-BOOK/
in FILES,in ERRATA
TEST RESULTS
IMR4227 was tested on 3/12/08 with a test with the powder at the rear on 3/26/08. The bullets used on 3/26 were slightly harder and lighter than the 3/12 bullets.
IMR4227, 14.5 GRAINS, 30/30, WLP PRIMERS
DATE 3/12/08 3/12/08 3/26/08 3/12/08
POSITION POWDER POWDER POWDER DACRON
FRONT LEVEL REAR WAD
MV AVG. 1353 1347 1457 1435
MV S. D. 19.0 17.5 24.3 14.3
IMR4198, 18.5 GRAINS, 30/30
DATE 3/12/08 3/12/08 3/26/08
POSITION POWDER POWDER POWDER
FRONT LEVEL REAR
MV AVG. 1614 1629 1650
MV S. D. 32.3 24.4 30.9
UNIQUE, 7.0 GRAINS, 30/30
DATE 2/6/08 2/6/08 2/6/08
POSITION POWDER POWDER POWDER DACRON
FRONT LEVEL REAR WAD
MV AVG. 1195 1214 1185
MV S. D. 28.1 39.3 14.3
UNIQUE, 8.5 GRAINS, 30/30
DATE 2/20/08 2/20/08 2/20/08
POSITION POWDER POWDER POWDER DACRON
FRONT LEVEL REAR WAD
MV AVG. 1346 1365 1378
MV S. D. 16.1 18.8 29.5
UNIQUE, 10.0 GRAINS, 30/30
DATE 2/20/08 2/20/08 2/20/08
POSITION POWDER POWDER POWDER DACRON
FRONT LEVEL REAR WAD
MV AVG. 1502 1519 1498
MV S. D. 28.8 22.3 19.5
UNIQUE, 14.0 GRAINS, 45/70
DATE 2/27/08 2/20/08
POSITION POWDER POWDER POWDER DACRON
FRONT LEVEL REAR WAD
MV AVG. 1195 1240
MV S. D. 28.0 15.8
SR4759, 22.0 GRAINS, 45/70
DATE 2/27/08 2/27/08
POSITION POWDER POWDER POWDER DACRON
FRONT LEVEL REAR WAD
MV AVG. 1128 1310
MV S. D. 35.5 31.8
IMR4227, 14.5 GRAINS, 30/30,REMINGTON 2 1/2 PRIMERS
DATE 3/12/08 3/12/08 3/12/08
POSITION POWDER POWDER POWDER DACRON
FRONT LEVEL REAR WAD
MV AVG. 1357 1357 1434
MV S. D. 30.4 35.5 22.7
Does the position of the powder in the cartridge case affect muzzle velocity, (MV) and/or the standard deviation, (STDEV) of MV?
I had tested the sensitivity of a powder by testing for increased accuracy with a minimum sized Dacron wad tamped down on the powder; and concluded that, for example, SR4759 and Unique are position sensitive in the 45/70 and IMR4227 is not position sensitive in the 32/40 and 30/30.
The testing conditions were expanded when I realized that my definition and test conditions were not complete (or correct); this epiphany occured after a lot of testing.
TESTING CONDITIONS
POWDER FRONT-hold the rifle with cartridge chambered at ~ a 45 degree angle down and slap the side of the rifle three times, then put it carefully on the rest.
POWDER LEVEL-put the rifle with cartridge chambered on the rest and slap the side of the rifle ten times.
POWDER REAR-hold the rifle with cartridge chambered at ~ a 45 degree or greater angle up and slap the side of the rifle three times, then put it carefully on the rest.
DACRON WAD-I recommend cotton but use Dacron wads. I use as small a wad as possible, a teased wad about dime to penny size, tamped down on top of the powder with a pencil.
I try to chronograph a minimum of 15 of each condition, shooting at 100 yards over my PACT chronograph.
Il record all results on an EXCEL workbook called "POWDER POSITION SENSITIVITY" and a WORD summary, this is it, called " POWDER POSITION SENSITIVITY TESTING". (See the EXCEL workbook for all the information about the loads and results.)
These two files will be on http://sports.groups.yahoo.com/group/CB-BOOK/
in FILES,in ERRATA
TEST RESULTS
IMR4227 was tested on 3/12/08 with a test with the powder at the rear on 3/26/08. The bullets used on 3/26 were slightly harder and lighter than the 3/12 bullets.
IMR4227, 14.5 GRAINS, 30/30, WLP PRIMERS
DATE 3/12/08 3/12/08 3/26/08 3/12/08
POSITION POWDER POWDER POWDER DACRON
FRONT LEVEL REAR WAD
MV AVG. 1353 1347 1457 1435
MV S. D. 19.0 17.5 24.3 14.3
IMR4198, 18.5 GRAINS, 30/30
DATE 3/12/08 3/12/08 3/26/08
POSITION POWDER POWDER POWDER
FRONT LEVEL REAR
MV AVG. 1614 1629 1650
MV S. D. 32.3 24.4 30.9
UNIQUE, 7.0 GRAINS, 30/30
DATE 2/6/08 2/6/08 2/6/08
POSITION POWDER POWDER POWDER DACRON
FRONT LEVEL REAR WAD
MV AVG. 1195 1214 1185
MV S. D. 28.1 39.3 14.3
UNIQUE, 8.5 GRAINS, 30/30
DATE 2/20/08 2/20/08 2/20/08
POSITION POWDER POWDER POWDER DACRON
FRONT LEVEL REAR WAD
MV AVG. 1346 1365 1378
MV S. D. 16.1 18.8 29.5
UNIQUE, 10.0 GRAINS, 30/30
DATE 2/20/08 2/20/08 2/20/08
POSITION POWDER POWDER POWDER DACRON
FRONT LEVEL REAR WAD
MV AVG. 1502 1519 1498
MV S. D. 28.8 22.3 19.5
UNIQUE, 14.0 GRAINS, 45/70
DATE 2/27/08 2/20/08
POSITION POWDER POWDER POWDER DACRON
FRONT LEVEL REAR WAD
MV AVG. 1195 1240
MV S. D. 28.0 15.8
SR4759, 22.0 GRAINS, 45/70
DATE 2/27/08 2/27/08
POSITION POWDER POWDER POWDER DACRON
FRONT LEVEL REAR WAD
MV AVG. 1128 1310
MV S. D. 35.5 31.8
IMR4227, 14.5 GRAINS, 30/30,REMINGTON 2 1/2 PRIMERS
DATE 3/12/08 3/12/08 3/12/08
POSITION POWDER POWDER POWDER DACRON
FRONT LEVEL REAR WAD
MV AVG. 1357 1357 1434
MV S. D. 30.4 35.5 22.7