Now, it's not a grease gun like this.
No, not that at all. Though you can see where the GI naming inspiration came from. That, and perhaps the fact that it often was a mechanic's weapon, especially recovery vehicle crews. And tank crews. And, well, anyone who was authorized a subgun vice a rifle or carbine.
Nor is it to be confused with a sub-machinegun, .45 caliber, M3A1, either, like that one up there. Because, since the one in the Arsenal Holdings is shootable, well, that would be *BAD* if it were a Sub-machinegun, .45 caliber, M3A1, since the state of Kansas declines to allow it's citizens to own functional fully-automatic weaponry, though the state to the right (when facing north) that is about 1.5 miles away, does. What's really funny about that is that the state to the right of us is where the event occurred (the Union Station Massacre) that caused the State of Kansas to get it's panties in a twist about private ownership of fully automatic weapons... even though the people who were using the fully automatic weapons in the state to the right were criminals and not likely to give a hoot about the law that Kansas passed. But that's a post of a different color.
No, that's a Valkyrie Arms SA M3A1 (SA not for Springfield Arsenal but rather Semi-Automatic) and is officially classified as a rifle. With short (dummy) display barrel, long barrel, and fake suppressor barrel that apes the OSS Silenced Grease Gun. The fake suppressed barrel was the Whatziss. To be a rifle, it has to meet certain barrel-length requirements, hence the long barrel. To meet the requirements of the Ugly Rifles That Scare Me Assault Weapons Ban the stock also had to be fixed. Though, with the lapsing of that law, apparently I can now send the weapon back to Valkyrie and they could retro-fit a collapsible stock. At least they offer the service, and I assume they don't want to go to jail. They actually make a pistol version now, which allows the short, original barrel, and has no stock, but, frankly, especially with a full magazine, I can't imagine that wouldn't be rather awkward. I assume that the barrels for the pistol have a different threading for the barrel - or idiots out there will buy pistol barrels for their carbines and create illegal weapons.
The Armorer will not, as he does not wish to move to 1300 Metropolitan Avenue from his current address, which serves his modest needs just fine.
The original grease gun came into being because of WWII. Colonel Thompson's fine M1928 series subgun was the only weapon of it's type in mass production when the war opened, but, while a sturdy and reliable piece it was heavy, very complicated to manufacture (requiring lots of skilled machinist time perhaps better spent on other things) and, as a result, expensive. It was also machined from solid billet steel, which was, well, somewhat wasteful of a strategic material, considering how much had to be machined away. Photos of a finished receiver available here, at Philadelphia Ordnance.
In it's ultimate form, the M1A1, the Thompson was greatly simplified - but still just too dang expensive to produce in terms of cost, time, and skilled workmen. There was a war on. Something Had To Be Done.
After a brief flirtation with the Marlin-Hyde M2 sub-machine gun which took too long to produce good prototypes, along came the M3 Grease Gun. A metal tube, some stampings, some welding, and the only serious machining being the barrel and bolt. Sanger thoughtfully provide a nice picture of the M3A1 while we were discussing, among other things... the Whatziss.
Firing from an open bolt (most subguns do, so that heat won't cook-off a round in the chamber) it was cocked with a lever on the side, which, in service, tended to catch on things, bend, and otherwise annoy the user. The safety was the ejection port cover, which had a flange that projected down into a hole in the receiver. Cocked, with the port cover open, the thing was dangerous... something that probably is weighing heavily on the minds of these German POWs in Brittany.
Some product improvements were made, resulting in the M3A1. The cocking lever was dispensed with, and the user just opened the ejector port cover, and stuck his finger in a hole in the bolt and pulled it back to cock it. The stock was modified so that it could be used as a wrench for removing the barrel (required for cleaning). One end of the wire stock had a socket for a cleaning brush, the other had a slot for cleaning patches. There was a metal doohickey (official term) that served as a magazine loader. The weak point of the M3 guns were the magazines. Instead of being double-column, double-feed, they were double-column single feed - which made them a bitch to load and caused some jamming problems. The gun had an oil reservoir and oil brush in the pistol grip. All in all a handy weapon, cheap to produce, and simple to use and maintain.
And it lasted a long time - the last combat hurrah of the M3A1 was Desert Storm. The Armorer also carried one when he was a battery commander, trading his M1911A1 (a nice 1943 Remington Rand) with the VTR driver for his Guide Lamp (a division of GM that made grease guns) M3A1.
It's fun to shoot, with a slow, steady beat that will allow a good shooter to shoot single shots as needed/desired. The longer barrel makes the .45 ACP go farther a little faster, and what it hits stays... hit, and is usually distracted by same. Hence my desire to carry one while I was a Battery Commander. If I needed to defend myself, I probably had even bigger problems in the battery area and wanted a weapon that would really influence my surroundings.
The semi-auto in the Holdings of the Arsenal of Argghhh! languished in lay-away for a long time, and is as-yet unfired. But, come better weather, the M3 will make a trip to the range - along with a really rare bird a buddy of the Armorer owns - a Pedersen device. Yes, boys and girls - the Armorer is going to shoot a weapon very very very few people have shot. A semi-auto M1903 rifle...
I did find this cool video of a silenced grease gun being fired in the Phillipines, and this video of an M3A1 being fired in a range - note the use of the finger to cock and the slow rate of fire.
For you Airsoft aficionados - here's the Hudson Airsoft Grease Gun being fired with "blue gas" and with "green gas".