Straight from the horse's mouth:
"WARNING: NEVER USE NON-STANDARD, RELOADED
OR "HANDLOADED" AMMUNITION WHICH HAS NOT
BEEN SUBJECTED TO INTERNAL BALLISTIC PRESSURE
TESTING. RELOADED OR HANDLOADED AMMUNITION,
MAY HAVE MANY MANUFACTURING AND QUALITY VARIABLES
(SUCH AS THE TYPE AND AMOUNT OF GUN POWDER).
ANY AMMUNITION THAT IS IMPROPERLY MANUFACTURED,
EVEN IN THE SLIGHTEST DEGREE, MAY FAIL TO FIRE
OR MAY GENERATE EXCESSIVE INTERNAL PRESSURES
WHICH CAN DAMAGE OR EVEN RUPTURE THE FIREARM,
CAUSING PERSONAL INJURY OR DEATH TO THE SHOOTER
OR THOSE IN THE IMMEDIATE VICINITY."