40 mm Grenade

© Brooke Clarke 2008

This is a low pressure munition.  Unlike high pressure munitions, like a rifle, that need very strong chambers and barrels, low pressure munitions can use thin walled barrels.  The heart of the system is the low pressure gas generator.  These gas generators are also used for things like automobile air bags, life vest inflation, life raft inflation, bolt cutters, grappling hooks, radio antenna launching.  This same system is used to launch mortars.

AAI stands for Aircraft Armaments Incorporated.  The origins of the 40 mm Grenade may be in explosive bolts used in Navy aircraft bomb racks.

In the past I had a surplus flare gun that took some impossible to get cartridge so made up an adapter shell.  It took a large pistol primer and fired a Ping Pong ball.  Some padding was needed to keep from burning a hole in the ping pong ball, but then it would shoot the ball over the power lines.  Based on this experience it may be possible to make a tennis ball launcher that could be used to put up wire antennas based on the high-low pressure system except using 22 rim fire blanks.

The current antenna launchers include:
Compressed gas driven tennis ball launchers.  They require a way to get the compressed gas and are more bulky than a cartridge type device.
Bow and Arrow suffers from the problem of doing severe damage when coming down.
Sling Shot and lead weight - has limited height capability.  I have 100+ feet tall pine trees and the sling shot at full extension can not get that high.

The first generation 40 mm grenade used the very common 0.38" blank pistol cartridge mounted in the base of the 40 mm round.  When the primer is fired gas is generated in the blank cartridge and the pressure builds up (30,000 psi) to the point where the brass case ruptures in places where the chamber in the 40 mm round has holes.  The high pressure gas expands into an empty space lowering the pressure (3,000 psi) which pushes the round out the 40 mm rifled barrel.  This is called the High-Low pressure system.  The high pressure is needed to properly burn the propellant that's commonly used in pistol rounds.

To replace the M-203.   Wiki - Flickr - Army - July 3, 2009 starting to be deployed

This is different from the XM25 7.62x51 NATO sniper rifle.  The XM-25 fires a 25mm round and utilities a lot of electronics and optical systems.
I wonder if the XM-25 uses a similar low pressure propulsion system?
This may or may not become a fielded weapon.
PEO Soldier unveils lighter, more lethal weapons systems -
ATK -Individual Airburst Weapon System (IAWS) -
XM-25 Is Readied For Prime Time -
defense Tech - Starship Troopers Meets G.I. Joe -

Wiki - Fires the 25mm smart round like the XM-25 above.
Intended to replace the MK 19 40mm (see below) and the 0.50 HB heavy machine gun.

40 mm practice rounds 1969 M385
These rounds do not use the .38 blank but might be using an aluminum 12 ga short blank?
Let me know

Patent Class Number

42 Firearms
89 Ordinance
102 ammunition
124 Mechanical Guns and Projectors (not explosive)

used gas pressure piped from rifle barrel

The propellant is contained in an expandable metal case that's sealed so no gas escapes

Calls:
2575071 Explosive Operated Device, G.O. Rockwell (Navy), Nov 13 1951, - The propellant is contained in an expandable metal case that's sealed so no gas escapes
3106131 Cartridge Actuated Device, I.R. Barr & N.J.La Costa (AAI), Oct 8 1963, -  The propellant is contained in an expandable metal case that's sealed so no gas escapes.  moves piston a fixed distance.
3119302 Gas Sealed Explosive Propelling Arrangement, I.R. Barr (AAI), Jan 28 1964, - separates adjacent bulkheads (explosively actuated separable bolt electric ignition
Called By:
3967552 Percussion ignition system for a smokeless, flashless, low noise cartridge Jul 6, 1976
3971322 Pressure actuated tube primer Jul 27, 1976
4047465 Telescoped explosive driver Sep 13, 1977
4406209 Projectile-firing weapons Sep 27, 1983
4549464 Inflatable, aerodynamic shroud Oct 29, 1985
4635443 Non-fouling actuating mechanism Jan 13, 1987
4671178 Low energy fuses Jun 9, 1987
5372071 Thrusting separation system Dec 13, 1994
5421263 Cartridge for spraying a liquid into the barrel of a firearm Jun 6, 1995
5493975 Cartridge for a power driven tool Feb 27, 1996
5585596 Thrusting separation system Dec 17, 1996
5834681 Reloadable high-low pressure ammunition cartridge Nov 10, 1998

Packaged unit for operating valves, cutting and splicing cable, actuating linkages, propelling masses, disconnecting components, initiating sequential operations, etc.
This particular one has a telescoping completely enclosed expansion chamber so can be used in explosive atmospheres

 looks like aircraft bomb rack?

Plunger is used to propel round while sealing the combustion gas preventing muzzle flash and noise

cites US patents from 1910 to 1946
does not look like for M16

this group of 3 patents covers clip fed semi auto launcher that fits under the barrel of a M16 rifle in a way similar to the M203

calls 3279114

a way for chopper crew members to fire the M384 HE round which normally has too much recoil for manual firing
barrel has gas bleed holes to lower pressure

telescoping chamber holds all combustion gas and flash inside the round so there's no muzzle flash and no explosive noise.  Cartridge case contains short rifled barrel.
Calls:
3951070 Non-hazardous ring airfoil projectile of non-lethal material Apr 20, 1976
3967552 Percussion ignition system for a smokeless, flashless, low noise cartridge Jul 6, 1976
4047465 Telescoped explosive driver Sep 13, 1977
4406209 Projectile-firing weapons Sep 27, 1983
4478150 Cartridge with elastic pusher cup Oct 23, 1984
5121692 Non-lethal, non-penetrating training bullet and cartridge with impact marking capability Jun 16, 1992
5686692 Single fuse follow-through grenade Nov 11, 1997
7194960 Non-lethal projectiles for delivering an inhibiting substance to a living target Mar 27, 2007

M79 type but must be newer

Calls:
89563 Cartridge, G.H. Daw, May 4 1869, 102/469 - rolled & soldered sheet metal tube, paper base
99899 Primer and Cartridge, B.B. Hotchkiss, Feb 15 1870, 102/470 -
116094 Method of Priming T.J. Powers, Jun 20 1871, 102/470 -
148366 Primers for Cartridges, A.C. Hobbs, Mar 10 1874, 102/470 -
278394 Cartridge Primer, J.H. Bullard, May 29 1883, 102/470 -
3728967 Tri-Pri Three Contact Primer,  Hinkle; Charles J. & Marquardt; Frank R. (Navy), Apr 1973 - electrically initiated primer
3771451 Low Pressure Ballistic System, W.B. Woodring (Olin), Nov 1973 - slow burning propellant.
3935816 Construction for cartridge Feb 3, 1976
3983817 Spotting projectile Oct 5, 1976
4164903 Shotgun wad for use as a practice projectile Aug 21, 1979
4370930 End cap for a propellant container Feb 1, 1983
4493263 Ballistic propulsion system Jan 15, 1985
4587905 Wad and slug for a shotgun cartridge May 13, 1986
4887674 Cartridge operated fire extinguisher Dec 19, 1989
4892038 Cartridged ammunition Jan 9, 1990
4913054 Projectile delivery apparatus Apr 3, 1990
5078117 Projectile propellant apparatus and method Jan 7, 1992
5086703 Universal projectile ammunition Feb 11, 1992
5259319 Reusable training ammunition Nov 9, 1993
5341744 Cleaning shell for firearms Aug 30, 1994
5353779 Self-contained cartridge for launching a low speed projectile Oct 11, 1994
5402729 Munition for low-pressure firing of projectiles from large-caliber guns Apr 4, 1995
5408931 Shotgun ammunition Apr 25, 1995
5429054 Tracer cartridges Jul 4, 1995
5493975 Cartridge for a power driven tool Feb 27, 1996
5703322 Cartridge having high pressure light gas Dec 30, 1997
5834681 Reloadable high-low pressure ammunition cartridge Nov 10, 1998
5936189 Cartridged ammunition Aug 10, 1999
6041712 Non-lethal cartridge with spin-stabilized projectile Mar 28, 2000
6189926 Airbag inflator with center discharge and soft onset Feb 20, 2001
6198718 Disc cartridge Mar 6, 2001
6230733 Self-contained rupture disk cartridge May 15, 2001
6328906 Chemical delivery systems for fire suppression Dec 11, 2001
6532402 Method for selecting a robotic mechanism best suited to perform a job from multiple robotic mechanisms in a storage library Mar 11, 2003
6619211 Practice ammunition Sep 16, 2003

Called By:
7373887 Expanding projectile May 20, 2008

10643205 Method and apparatus for performing reconnaissance, intelligence-gathering, and Surveillance over a Zone, P. Rayond, V. Wegner & W. Knorr - hand launched from tube.

11225807 Deployable Monitoring Device having Self-Righting Housing and Associated Method, Y.W. Chang, W. Grainger, M Johnson, W. Traeger, P.D.L. Rios, W. Osterholm  - sits on floor hostage situation
US 2006/0283345 A1Surveillance projectile, P.H. Feldman, M.J. Ray, J.F. McNutly, filed Jun 16 2005 - 40 mm round fired into building with: IR light source, Audio Tx, Video Tx, etc.  Switch turns on unit when it leaves barrel.

3054208 Firing Mechanism for a Spotting Rifle, S.D. Silsby (Army), Sep 18 1962, 42/70.08 ; 42/106; 89/27.11 - has two safeties, one for each of the two man team
3010370 Controlled Burst Firing Mechanism, S.D. Silsby (Army), Nov 28 1961, 89/129.02 - maybe 3 rounds for M16
3204529 Controlled Burst Firing Mechanism, S.D. Silsby (Army), Sep 7 1965, 89/140 ; 89/129.02; 89/149 - filed May 4, 1964
3345771 High Capacity Magazine and Cooperating Firearm, S.D. Silsby (Army), Oct 10 1967, 42/18 ; 42/50 - filed Jan 7, 1966 - two mags each with staggered cartridges side by side

Ruger SP101 357 Mag Revolver
Hammerlli M150 Free Pistol
FN FAL ".308 Match" Rifle
Daisy BB Rifle
Survival Kit with Pocket Pen Gun flare launcher