The right hand end on the drawing is obviously the firing aperture. The rear of the firing tube vents some of the overpressure gasses to reduce recoil. (The plasma pellets may be of light mass, but they still deliver a kick which the recoilless mechanism compensates for.) Backblast is minor, but I wouldn't stand in the way.

At the front is a small blast shield. The chance of particulate matter blowing back is tiny, but Cadmium Telluride dust is a toxic hazard if ingested. The shield prevents it travelling back along the boundary layer along the surface of the firing tube.

Two-thirds back along the tube is a shaped plastic shoulder rest on the left hand side (not shown). On the right side is the flip-open casing for the ammo feed and magazine. FYI, inside the tube here are the laser collimator and the magnetic coils, so most of the critical electronics are around this location. The weapon's balance point is around here also.

Clipped to the top of the casing is the sighting optics. A video eyepiece offsets to the left (i.e. Where the firer's eye is).

Forward of this is a handgrip on the right hand side. This is an adjustable grip that swings downward from a front hinge and is gripped in the right hand. There is a broad bar on the inside (on top in the illustration) - a 'dead man' switch which must be squeezed to prime the weapon for firing. On the grip is a firing button that must be depressed to fire (not shown).

NB It's not a pistol grip _per_se_, though it is used to steady and aim the weapon. It's a fairly chunky piece of metal and plastic; a real handful. I once saw this big Colonial Marine sergeant fire one on the range and it almost looked bigger than his hand could encompass. He said it was comfortable, though. The pivot point is on the forwardmost corner, by the tube. The pivot is notched so you can pull it down and it holds its position.

The dead man switch is squeezed with the palm. There's actually two detents to this switch. The first detent activates a diagnostic which reads out data to the video eyepiece. The manual recommends this is run before each engagement. The second detent primes the weapon for firing by cycling the discharge generator. This takes about 3 seconds. Once primed the charge can be held for only about 20 seconds before the weapon must either be fired or powered down.

Anyway, once primed, the firing control is a round button, placed about 10 o'clock on the grip.

Since the right hand is used to hold the firing grip and aim, the left hand cups the firing tube to the left side or top of the weapon for additional stabilization.

The ‘bumper’ under the muzzle is plastic. Actually, its main function is more like a guard - to prevent the user sliding their hand
too close to the firing aperture. But you can also use it as a rest.

By the way, there's a slight hum from the power pack as the discharge generator runs up. It's a tiny, low noise, but noticeable from a few metres away, and can be detected by infrasonics. The M78A2 is supposed to fix this problem. Extra shielding or something. But it's going to be another year or so before it's released into service, and the Army are getting it first. Colonial Marines I spoke to are pissed at being way down the appropriations list, as usual.

The thing that freaks most people about the PIG is the sound - or lack of it. It's like a loud, asthmatic "PAH" noise. Much quieter than an unsilenced pistol.

Just a quick word on usage. A Marine LTC I once talked to said his men don't use the weapon against Panzers. They reckon it's not much use against medium armour on the glacis and you have to angle for flank shots. And anyway, the sighting system is useless against modern optical camo and shielded IR. Their primary use for the thing is in reducing bunkers, sangars, foxholes and the like. The PP ammo goes clean through all but the most packed earthen banks and slices through most forms of 'crete. In a nice confined space the plasma disperses in a superheated ball and roasts the occupants.

They use this sort of thing in MOUT (Military Operations in Urban Terrain) as well, only there are two problems there: first is the backblast which is small enough to be relatively harmless in a confined space, but may still stir up dust and give away your position. The other problem is that it makes neat, tiny holes in walls. What the Marines want in MOUT is something that will make a breach big enough to shoot through or even climb through.

He was less than complimentary about my work but he did offer to correct the plans for me.

And as for the AT4, doesn't it have a more domed shape attached to the hexagonal part?