Powder Position Sensitivity

[joeb33050]

i WISH SOMEONE WOULD SHOW ME HOW TO PUT THIS WORD FILE HERE SO IT CAN BE READ. ANYONE???????????????????????????????????????????? ???????
JOE B.




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 are and will be on http://sports.groups.yahoo.com/group/CB-BOOK/ in FILES,in ERRATA

AVERAGE VELOCITY
DATE CALIBER POWDER GRAINS POWDER FRONT POWDER LEVEL POWDER REAR DACRON WAD
2/6/2008 30/30 Unique 7.0 1,195 1214 1185
4/9/2008 30/30 Unique 7.0 1163 1175
2/20/2008 30/30 Unique 8.5 1346 1365 1378
4/9/2008 30/30 Unique 8.5 1337 1368
2/20/2008 30/30 Unique 10.0 1502 1519 1498
4/9/2008 30/30 Unique 10.0 1491 1478
2/27/2008 45/70 Unique 14.0 1195 1240
4/16/2008 45/70 Unique 14.0 1173 1216

2/27/2008 45/70 SR4759 22.0 1128 1310
4/16/2008 45/70 SR4759 22.0 1195 1241

3/12/2008 30/30 IMR4227 14.5 1353 1347 1435
3/12/2008 30/30 IMR4227 14.5 1357 1357 1454 Rem 2 1/2
3/26/2008 30/30 IMR4227 14.5 1457
4/9/2008 30/30 IMR4227 14.5 1392 1451
4/16/2008 30/30 IMR4227 14.5 1424 1422

3/26/2008 30/30 IMR4198 18.5 1614 1629 1650



STANDARD DEVIATION OF VELOCITY
DATE CALIBER POWDER GRAINS POWDER FRONT POWDER LEVEL POWDER REAR DACRON WAD
2/6/2008 30/30 Unique 7.0 28.1 39.3 14.3
4/9/2008 30/30 Unique 7.0 17.8 19.8
2/20/2008 30/30 Unique 8.5 16.1 18.8 29.5
4/9/2008 30/30 Unique 8.5 16.6 29.3
2/20/2008 30/30 Unique 10.0 28.8 22.3 19.5
4/9/2008 30/30 Unique 10.0 46.0 11.3
2/27/2008 45/70 Unique 14.0 28.0 15.8
4/16/2008 45/70 Unique 14.0 27.5 9.8

2/27/2008 45/70 SR4759 22.0 35.5 31.8
4/16/2008 45/70 SR4759 22.0 31.4 21.6

3/12/2008 30/30 IMR4227 14.5 19.0 17.7 14.3
3/12/2008 30/30 IMR4227 14.5 30.4 25.5 22.7 Rem 2 1/2
3/26/2008 30/30 IMR4227 14.5 24.3
4/9/2008 30/30 IMR4227 14.5 26.1 20.6
4/16/2008 30/30 IMR4227 14.5 13.1 14.6

3/26/2008 30/30 IMR4198 18.5 32.3 24.4 30.9

[compass will]

PM sent your way!
Will

[runfiverun]

wooohoooo
joe please post your observations with this.

[joeb33050]

wooohoooo
joe please post your observations with this.

I'm trying to figure out if the variation is due to a bad chronograph or is as should be expected.
I'm getting big vel variations with small bullet wt./hardness variations, everything else the same.
It's too soon for me to make any conclusions. I'd like to see someone test with a 30/06 and cast and Unique.
The data presents more questions than answers so far.

joe b.

[txbirdman]

I read an opinion by Ed Harris once in which he said (as I recall) that position sensitivy could be mostly negated by the use of Winchester primers. This had something to do with the material from with they are made and the way it was disbursed throughout the case at ignition. Now if I could just remember where I read that.

[runfiverun]

it was on the cba forum i talked to ed about this i guess that win uses some type of aluminum
in their mix spaghnate/styphnate? something like that it kinda "spits" fire one in an empty case in the dark garage you will see.

[joeb33050]

it was on the cba forum i talked to ed about this i guess that win uses some type of aluminum
in their mix spaghnate/styphnate? something like that it kinda "spits" fire one in an empty case in the dark garage you will see.

The EXCEL workbook shows the results of a test of this theory.
I use LP primers in (almost) all cast loads,WLP because they're available, but I like Rem 2-1/2-not as available.
In 30/30, 311299, 14.5/IMR4227
Velocities and SDs
Powder Powder Dacron
Primer Front Level Wad
WLP 1353 1347 1435
2-1/2 1357 1357 1454

WLP 19.0 17.7 14.3
2-1/2 30.4 25.5 22.7

It's pretty clear to me that Winchester primers, in this test:
Don't negate the effect of powder position
Don't vary velocity
Do-maybe-reduce SD.
joe b.