cole
06-25-2008, 20:34
The table attempts to illustrate the comparison data in percentages. It presents average/typical results for a load. Velocity, expansion and penetration will vary. However, the relationship and correlations of the data can be expected to remain relatively consistent.
The main idea was to translate numeric differences to percentages. The numeric values of load data are often so small to begin with it's far more difficult to appreciate differences when looking only at the small numeric differences that can be measurably large on the relatively small scale of the load comparison data.
Folks also confuse diameter with surface area when considering expansion. This is a fundamental error that also makes differences appear small when they are not. Percentages establish a comparable scale of difference for outcomes.
Reading the table
Example #1: The 230gr .45acp has 7.1% more momentum than the 180gr .40sw
Example #2: The 115gr 9mm has 12.5% more energy than the .45acp
Example #3: The 180gr .40sw has 18.3% more mass than the 147gr 9mm
Example #4: The initial surface area of the .45acp is 37.8% greater than 9mm
Example #5: The expanded surface area of the .40sw is 8.8% greater than 9mm.
Example #6: Penetrating 13” is 8.3% more penetration than 12”.
The "Seconds" table relates to recovery from recoil for follow-up shots.
Actual Data Example: Load Test Data (http://glocktalk.com/forums/showthread.php?t=868400)
Test-to-Test Comparison Data, Overall Outcomes, All Shot Scenarios
Summary, Sorted by Penetration, at least 4 tests (w/out FBI and BC*)
Caliber Weight Penetration Expand, Ave.
.40sw 180 13.44 0.67
.45acp 230 13.35 0.76
9mm 147 12.78 0.64
9mm 124 12.40 0.65
9mm 127 12.28 0.62
Interpretation:
1) The 230gr .45acp has 22.3% greater expansion (surface area) with 99.3% the penetration of the 180gr .40sw
2) The 180gr .40sw has 8.8% greater expansion (surface area) with 5.2% greater penetration than the 147gr 9mm
3) The 230gr .45acp has 29.1% greater expansion (surface area) with 4.5% greater penetration than the 147gr 9mm
Math:
Momentum = Mass x Velocity
Energy = Mass x Velocity Squared (e=mc2)
Area of a Circle = Radius x Radius x 3.14 (r*r*Pi)
Radius = Diameter / 2 (d/2)
Reference the table as you like. Skill is priceless, but skill does not trump the science once the good shot is made. The data reflects comparable performance given identical shot placement.
The Energy table can be seem as a relative comparison of predicted/expected recoil as energy forward relates somewhat to energy back.
Please feel free to check the math.
Side note: One thing to remember about small differences in percentages (i.e. the concept of statistics) is that they all can seem small until you are that difference.
I’ll update the table as I have more to add.
http://glocktalk.com/forums/attachment.php?attachmentid=155999&stc=1&d=1219525282
Illustration, Initial Diameter
http://glocktalk.com/forums/attachment.php?attachmentid=151199&d=1212564049
The main idea was to translate numeric differences to percentages. The numeric values of load data are often so small to begin with it's far more difficult to appreciate differences when looking only at the small numeric differences that can be measurably large on the relatively small scale of the load comparison data.
Folks also confuse diameter with surface area when considering expansion. This is a fundamental error that also makes differences appear small when they are not. Percentages establish a comparable scale of difference for outcomes.
Reading the table
Example #1: The 230gr .45acp has 7.1% more momentum than the 180gr .40sw
Example #2: The 115gr 9mm has 12.5% more energy than the .45acp
Example #3: The 180gr .40sw has 18.3% more mass than the 147gr 9mm
Example #4: The initial surface area of the .45acp is 37.8% greater than 9mm
Example #5: The expanded surface area of the .40sw is 8.8% greater than 9mm.
Example #6: Penetrating 13” is 8.3% more penetration than 12”.
The "Seconds" table relates to recovery from recoil for follow-up shots.
Actual Data Example: Load Test Data (http://glocktalk.com/forums/showthread.php?t=868400)
Test-to-Test Comparison Data, Overall Outcomes, All Shot Scenarios
Summary, Sorted by Penetration, at least 4 tests (w/out FBI and BC*)
Caliber Weight Penetration Expand, Ave.
.40sw 180 13.44 0.67
.45acp 230 13.35 0.76
9mm 147 12.78 0.64
9mm 124 12.40 0.65
9mm 127 12.28 0.62
Interpretation:
1) The 230gr .45acp has 22.3% greater expansion (surface area) with 99.3% the penetration of the 180gr .40sw
2) The 180gr .40sw has 8.8% greater expansion (surface area) with 5.2% greater penetration than the 147gr 9mm
3) The 230gr .45acp has 29.1% greater expansion (surface area) with 4.5% greater penetration than the 147gr 9mm
Math:
Momentum = Mass x Velocity
Energy = Mass x Velocity Squared (e=mc2)
Area of a Circle = Radius x Radius x 3.14 (r*r*Pi)
Radius = Diameter / 2 (d/2)
Reference the table as you like. Skill is priceless, but skill does not trump the science once the good shot is made. The data reflects comparable performance given identical shot placement.
The Energy table can be seem as a relative comparison of predicted/expected recoil as energy forward relates somewhat to energy back.
Please feel free to check the math.
Side note: One thing to remember about small differences in percentages (i.e. the concept of statistics) is that they all can seem small until you are that difference.
I’ll update the table as I have more to add.
http://glocktalk.com/forums/attachment.php?attachmentid=155999&stc=1&d=1219525282
Illustration, Initial Diameter
http://glocktalk.com/forums/attachment.php?attachmentid=151199&d=1212564049
