SOUNDSUPPRESSORMODEL MK-9K P. 7
AMMUNITION NOTES
WARNING
Never use ammunition that does not meet SAAMI specifications.
AllcommercialAmericanmadeSAAMIspecificationammunitionis safe,
but the origins, storage history, and reason for being surplussed of foreign
madeammunition is notavailable for evaluation.Although foreignmade am-
munition is usually safe, this is not always the case. Damage from non-
Americanammunition cannot becoveredunder warranty.
Themajority of 9mm ammunition issupersonic, and the projectiletrav-
eling at velocities above 1,100 fps will produce a ballistic “crack” or “sonic
boom”. There are several commercial sources of specially loaded subsonic
9mm ammunition, and for maximum effectiveness, we suggest the use of
this type ammunition. Although special 9mm subsonic ammunition has a
bullet muzzle velocity below 1,100 fps, the higher bullet weight results in a
significantly higher bullet kinetic energy.
The majority of subsonic 9mm ammunition is loaded utilizing bullet
weightsof 147grainor heavier.Subsonic ammunitionutilizing bullet weights
of 155 grain or more is apt to be significantly overpressured in some weap-
ons,especially the HKMP5.147 grainFMJand JHP bulletsfor9mm reload-
ingareavailablefromavariety ofsuppliers, includingHornady andSpeer. Do
not use cast lead bullets.Loading data for 9mm subsonic ammunition is
available from a number of sources, including the Speer Supplement (avail-
ablefrom Speerfor their 147grainTMCbullets),andfromAccurateArms for
use with their powders. However, we caution against any attempt to hand
load beyond recommended SAAMI specifications.
Commercial subsonic ammunition is available in 158 grain FMJ from
Israeli Military Industries and in 147 grain bullet weight from Winchester,
Remington, Federal, CCI, and others in both full metal jacket and hollow
pointstyles. We havefound that althoughthis ammunition remainssubsonic
in pistols, it may not remain subsonic in the longer barrel of the Heckler &
Koch MP5 submachine gun. The user will need to experiment with different
brands. Ammunition with bullet weights over 154 grains is discouraged by
H&K. Although some have suggested that the 9mm subsonic cartridge is
“downloaded,” we believe users should be aware that this ammunition is
anything but an anemic load with kinetic energies and pressures signifi-
cantly greater than standard 9mm ball ammunition.
Useof corrosive ammunition, andevidenceof its use, willvoidthe war-
ranty.
