The information on this page could be dangerous! The source of each piece of information is listed, check the original documents BEFORE using this data! If you are an idiot, play somewhere else. All information is for use at YOUR OWN RISK!
No-cost reloading decapping pins:
Needle bearings from discarded universal joints make great decapping pins!
p.64 National Rifleman Jul 86
Half Power .223 Loads
50-60 Gr. Jacketed Bullet
use 10.0 to 11.0 grains of 2400 Powder
use sml. square of kleenex for filler
results in about 2,000 fps
p.17 HL#45, Sept-Oct 1973
Brinell Hardness Number (BHN) vs. Max PSI
BHN * 1422 = Max PSI
Pure Lead (BHN of 4.2) allows up to 5,972.4 PSI
Wheelweights (BHN of 14.5) allows up to 20,619 PSI.
Handloader #165, Sept/Oct 1993, p.4 to 5
Formula to determine new powder weight when using new bullet weight:
(3/8) * (old powder charge/old bullet weight) * (old bullet weight-new bullet weight)
add/subtract result to original powder charge weight.
p.36 HL#126 Originally from translated Soviet ballistics book!
Revolutions per second (RIFLING FORMULA):
(feet/second) * (12/1) * (turns/inch)
Minimum Twist Rate
150/(length of projectile in calibers)
Gives twist rate in calibers. Multiply by caliber to get # of inches.
Jan-Feb 1989 HL
Minimum Twist Rate CAST BULLET ADJUSTMENT:
It should be pointed out that many shooters believe that to determine the required twist for a given cast bullet, a factor of 125 should be used instead of 150.
Apr-May 1995 HL #174
DuPont's IMR-3031 powder is grain for grain equivalent of cordite.
DuPont's IMR-4831=(1.333*cordite charge)
HL#70 NOV/DEC 1989
Effects of barometric readings on ballistic coefficient:
A drop of 1" in the barometric reading will increase the ballistic coefficient by about 3-1/3%.
NRA Firearms Factbook, 3rd Ed., p.242
Speed of Sound:
At freezing (+32 degrees Fahrenheit or 0 Celsius), the speed of sound is 1,090.5 fps. For each degree of temperature rise (Fahrenheit), the speed increases by 2.0 fps.
Handloader, #171, p.33
CASE CAPACITY (VOLUME) FORMULA:
|Temperature in Degrees (Fahrenheit)||Speed of Sound (fps)|
a - Weight of empty case
b - Weight of case filled with water
c - 252.8 grains (weight of 1 cubic inch of water)
X(Case Volume) = (b-a)/c
Assume all weights are in grains and volume is in cubic inches.
Handloader's Digest/1995, Inside back cover
BALLISTIC COEFFICIENT OF A STANDARD AIRGUN PELLET:
According to a source on the Internet, .0200 is the BC of a typical pellet. Seeing as how I don't see much in the way of super-sonic pellet loads, it probably doesn't matter to many people.
Change of Powder Vs. Change in Velocity/Pressure
. . . when you change the amount of powder. If you change the weight by a given percentage, inside the same case, the velocity changes by the SAME GIVEN PERCENTAGE. However, at the same time, the pressure changes by TWICE THE GIVEN PERCENTAGE. . . . all these figures apply to small changes in loading only. Furthermore, if you are otherwise working at maximum loads, do not use these figures.
Powley Instruction Manual, as quoted in Modern Handloads by Nonte, 1972 Winchester Press.
This page sourcecode was last updated:
August 27, 2013