joeb33050
02-21-2008, 08:55 AM
POWDER POSITION SENSITIVITY TESTING
Does the position of the powder in the cartridge case affect muzzle velocity, (MV); does powder position affect the standard deviation, (STDEV) of MV; and does that position affect accuracy?
Powder is moved to the FRONT of the cartridge case by holding the rifle at ~ a 45 degree angle and slapping the side three times, then putting it carefully on the rest.
Powder is positioned LEVEL in the case by putting the rifle on the rest and slapping the side ten times.
Powder is positioned to the REAR of the case by pushing a wad down on the powder.
I recommend cotton but use Dacron wads. Use as small a wad as works. I use a teased wad about dime to penny size, and push it on top of the powder with a pencil.
These loads, 15 of each last time out, are shot at 100 yards over my PACT chronograph.
I'll 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
Testing to date:
2/6/08, 7.0 Unique, .30WCF M54 Winchester
LEVEL
MV(fps) 1214
MV STDEV (fps) 39.3
GROUP AVG (") 2.33
FRONT
MV(fps) 1195
MV STDEV (fps) 28.1
GROUP AVG (") 2.51
REAR
MV(fps) 1185
MV STDEV (fps) 14.3
GROUP AVG (") 2.25
2/20/08, 8.5 Unique, 30WCF M54 Winchester
LEVEL
MV(fps) 1365
MV STDEV (fps) 18.8
GROUP AVG (") 2.65
FRONT
MV(fps) 1346
MV STDEV (fps) 16.1
GROUP AVG (") 1.35
REAR
MV(fps) 1378
MV STDEV (fps) 29.5
GROUP AVG (") 1.84
2/20/08, 10.0 Unique, 30WCF M54 Winchester
LEVEL
MV(fps) 1519
MV STDEV (fps) 22.3
GROUP AVG (") 1.68
FRONT
MV(fps) 1502
MV STDEV (fps) 28.8
GROUP AVG (") 1.56
REAR
MV(fps) 1498
MV STDEV (fps) 19.5
GROUP AVG (") 2.24
The bullets were tipping.
There's nothing here suggesting that powder position has any predictable affect on MV or MV STDEV or group size. Next on the schedule is the 45/70 and Unique.
Does the position of the powder in the cartridge case affect muzzle velocity, (MV); does powder position affect the standard deviation, (STDEV) of MV; and does that position affect accuracy?
Powder is moved to the FRONT of the cartridge case by holding the rifle at ~ a 45 degree angle and slapping the side three times, then putting it carefully on the rest.
Powder is positioned LEVEL in the case by putting the rifle on the rest and slapping the side ten times.
Powder is positioned to the REAR of the case by pushing a wad down on the powder.
I recommend cotton but use Dacron wads. Use as small a wad as works. I use a teased wad about dime to penny size, and push it on top of the powder with a pencil.
These loads, 15 of each last time out, are shot at 100 yards over my PACT chronograph.
I'll 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
Testing to date:
2/6/08, 7.0 Unique, .30WCF M54 Winchester
LEVEL
MV(fps) 1214
MV STDEV (fps) 39.3
GROUP AVG (") 2.33
FRONT
MV(fps) 1195
MV STDEV (fps) 28.1
GROUP AVG (") 2.51
REAR
MV(fps) 1185
MV STDEV (fps) 14.3
GROUP AVG (") 2.25
2/20/08, 8.5 Unique, 30WCF M54 Winchester
LEVEL
MV(fps) 1365
MV STDEV (fps) 18.8
GROUP AVG (") 2.65
FRONT
MV(fps) 1346
MV STDEV (fps) 16.1
GROUP AVG (") 1.35
REAR
MV(fps) 1378
MV STDEV (fps) 29.5
GROUP AVG (") 1.84
2/20/08, 10.0 Unique, 30WCF M54 Winchester
LEVEL
MV(fps) 1519
MV STDEV (fps) 22.3
GROUP AVG (") 1.68
FRONT
MV(fps) 1502
MV STDEV (fps) 28.8
GROUP AVG (") 1.56
REAR
MV(fps) 1498
MV STDEV (fps) 19.5
GROUP AVG (") 2.24
The bullets were tipping.
There's nothing here suggesting that powder position has any predictable affect on MV or MV STDEV or group size. Next on the schedule is the 45/70 and Unique.