View Full Version : M-3 Grease Gun .45

January 21, 2011, 10:24 AM
Anybody ever fire one? Looks like fun:

January 21, 2011, 10:29 AM
Yes, in the 80's I fired one on several occasions in the Cav. At the time, they were still issued to armor crews. I found them to be very reliable and if aimed, accurate out to a bit past 50 meters.

Art Eatman
January 21, 2011, 10:34 AM
In 1955, I was coming back from a supply run from the QM at Yongdongpo. My shotgun guard, Mousie, was in the back of the deuce and a half with a grease gun. When we stopped at an intersection, a Korean slicky-boy jumped in, with the usual intent of throwing boxes out on the street for his buddies to grab and run.

Mousie cut loose.


January 21, 2011, 10:40 AM
My bro-in-law and I rented one at a range in Bandera TX, last summer, it was a blast! PUN INTENDED!

January 21, 2011, 10:52 AM
yes, I fired it last year. I preferred it over UMP in 45ACP and also, Thompson.

January 21, 2011, 01:04 PM
interesting how the bolt stays back before firing...much slower than the Thompson which I would imagine would be a positive.

January 21, 2011, 03:41 PM
I have the MAC-10 (uses the same magazine) in semi-auto.
Still M/T a mag in about 12 seconds.

Saving for an UC9 to make it less expensive to shoot.


January 21, 2011, 03:43 PM
interesting how the bolt stays back before firing...much slower than the Thompson which I would imagine would be a positive.

That's an open bolt operation. The advantage of the open bolt design is that you decrease the possibility of a cook off during sustained firing (also the same way on most LMG's/MG's).

January 21, 2011, 04:29 PM
interesting how the bolt stays back before firing...much slower than the Thompson which I would imagine would be a positive.
That's an open bolt operation. The advantage of the open bolt design is that you decrease the possibility of a cook off during sustained firing (also the same way on most LMG's/MG's).

hmm interesting thanks!

January 21, 2011, 08:16 PM
A Grease Gun story.

I went to watchmakers school with a WWII vet.
He told me about being an MP in Colorado before shipping to Europe for D-Day.

He said that one morning they were ordered to bring their Grease Guns to a warehouse.
They were loaded onto a large flat bed tractor trailer and driven down to the Denver mint.
The flat bed was loaded bags of silver dollars.
They drove through downtown Denver sitting on the bags of silver dollars with loaded Grease Guns.

The silver dollars were used to pay the soldiers at an Army post before being given their last leave before shipping out.
He said your pockets were about to tear out from the weight of the silver dollars they were paid with.

He said that almost every dollar was back in the mint within about 3 days.

January 21, 2011, 09:09 PM
I have fired it several times,and I have to say it's a handfull of fun as the Mac 10 (fully automatic), and the Thompson. Of the three the Mac10 was the fastest, the M3 was the coolest, and the Thompson was sweet also. Totally " happydays" when firing these dudes!!:D

January 21, 2011, 09:38 PM
The advantage of the open bolt design is that you decrease the possibility of a cook off during sustained firing (also the same way on most LMG's/MG's).

And you could take that a step farther and say helping it cool faster in general, which is a huge benefit.. although if you have sustained fire for any length of time you know you're gonna be breathing in smoke from your lubricant getting burned.. not fun at all. It also means you never have a loaded round in the chamber with the bolt closed.

Mousie cut loose.

Great story, made me laugh.. what happened to all the good nicknames though?

January 22, 2011, 12:49 AM
I wouldn't mind owning one, but given the choice of a grease gun over the UMP I'm afraid I'd go with the UMP.

Mike Irwin
January 22, 2011, 01:07 AM
Firing from an open bolt also decreases the overall design complexity of the weapon. In essence, it becomes a slam-fire weapon with a fixed firing pin.

As originally designed the Thompson used a hybrid method of firing from an open bolt in which the bolt, on closing, activated a hammer that swung forward and hit the firing pin to fire the cartridge.

That system was overly complex and during World War II the Thompson was redesigned to use a fixed firing pin. Complexity was signficantly decreased, it became cheaper and easier to manufacture, and reliability didn't suffer one bit.

January 22, 2011, 01:42 AM
One time in the Guard, I had to expend 2000 rounds of match-grade .45 ammo, so I grabbed a couple of M3A1s from the arms room (we still used them for armored vehicle crewman).

I'm not sure which was cooler: Actually firing them, or just walking around with them all weekend at the base.

I have a favorable opinion of the grease gun. It's compact, handy and I don't remember having any stoppages. Mechanically, it's simple, safe and sturdy. I would definitely like to carry one, but only because it looks so cool.

It has a perceptable locktime, so that you pull the trigger and wait for the bolt to "ker-thump" forward. Firing was controlable, and it was fun to blast away: "K-chunk, K-chunk, K-chunk...".

For a "Dirty Dozen" kind of mission, kicking in doors and spraying rooms, I think it's great. More of a PDW than a real offensive weapon.

January 22, 2011, 04:56 AM
I fired my M-3A1 in Germany in 67 / early 68 quite a few times. Interesting but no where near as fun to shoot as my TC position weapon, a M-2 50!!!

As stated, all of us tankers were issued the things. We even were issued them when I got to RVN in Sep, '68 but soon traded them for M16A1s which were a pain to store in our M48.

January 22, 2011, 06:27 AM
I ran over one, once upon a time.

Leading a platoon of tanks down a large hill, I must've thought I was Rambo, because I had my M3A1 slung over my shoulder and the gun was outside the turret. That crappy cotton sling parted and my gun slid down the side of the turret to the road below. Second tank couldn't stop and rolled over it. Third tank got it with the left track.

I got the column stopped, collected the parts and continued the march. When we got back into garrison, I took it to the supply sergeant to turn in. He looked at it. "We got a problem here, Lieutenant. We can either do a Report of Survey, which is going to take reams of paperwork and three months, or someone can admit responsibility and pay the government for this crappy little gun."

"How much?" Asks I.

"I'll check." says he.

Long story short, the government depreciated that M3A1 and I wrote a check to the Treasurer of the United States for the princely sum of $4.67.

I wish I could buy a case of them for that amount.

It has a perceptable locktime, so that you pull the trigger and wait for the bolt to "ker-thump" forward. Firing was controlable, and it was fun to blast away: "K-chunk, K-chunk, K-chunk...".

I had forgotten about that. K-chunk, K-chunk, yeah, those were good times.

Mike Irwin
January 22, 2011, 07:04 AM
Fired at roughly 400 rounds a minute. Once you got used to the trigger you could easily fire single shots, or doubles or triples without really thinking about it.

I fired one a couple of times some years ago and they were a lot of fun.

44 AMP
January 22, 2011, 03:36 PM
The M3/M3A1 fire from the open bolt. They have a fixed firing pin. The only way you can have a round in the chamber with the bolt closed is if the round fails to fire. I worked on Grease guns as a small arms repairman in the 70s in Europe. Rugged little beasts, generally. Slow rate of fire, compared to other SMGs. The only things that go wrong with them is bent stocks, and the tab of the spring that locks the barrel nut in place can break off.

The "safety" is the ejection port cover. There is a tab that sticks down, and holds the bolt in position (either open or closed) when the cover is closed. Rarely these do break, but only rarely. Any time you see a Grease Gun with the cover open and a mag in the well, it is dangerous. We have proven many times that a sharp jar to the gun with the bolt forward (cover open) can jar the bolt back far enough (without going back far enough to be caught by the sear) to strip a round from the mag and fire it when the bolt goes forward.

A simple design, constructed mostly of heavy stampings (made buy the Guide Lamp Division of GM, the people who made car headlights before the war), it is rugged, durable, accurate enough for close range, lighter and handier than the Tommygun. ALso a LOT cheaper. The govt reportedly paid a whopping $17.50 each when new. So I find the story of the depreciated one being $4.67 quite likely.

Grease gun mags are stout, and have heavily constructed feed lips, seldom giving any trouble (unless run over by a tank:D), the bolt is massive, weighing nearly as much as the entire rest of the weapon, or seeming to. They are an effective close combat weapon, crude appearing, cheap to make, pretty durable (tanks excepted;)) and a great value to the military for the money.

I don't know if any are still in front line service today, probably not. But 40 years ago, they were still the arm for armor crewmen, and I got to say, that if someone was trying to climb on/in my tank, I'd much rather be able to grab a grease gun than any M16 variant.

January 22, 2011, 09:12 PM
The M3 was the second full auto firearm I shot.

The first one was a Thompson. The Thompson had the famous silhouette and the cool factor was high. I shot the M3 better because the rate of fire was so much slower.

Later, I shot a suppressed M3 in a side match called, Raptor Road, at the old Second Chance Bowling Pin Shoot. The clank of the 230 grain FMJ rounds hitting the steel targets was louder than the suppressed M3.

If I could, I'd own an M3. Unfortunately, the guns that cost about six bucks to be manufactured cost an arm and a leg now. Not many made it out of government hands into the private collectors sector.

James K
January 23, 2011, 12:05 AM
I owned an M3 for many years but the M3A1 is a better gun. That gun looks simple but the design is ingenious and very good. The idea of having the bolt ride on rods (later used on the AR-18) is an excellent one, effectively eliminating any problems from dirt getting into the action. Having the ejection port cover double as a safety is also a great idea.

In addition, the M3A1 has the neat idea of eliminating the operating handle by just having a hole in the bolt. And it has some other good features, like the extendible stock that doubles as a magazine loader and also has a threaded hole in one arm to take a wire brush or a slotted tip for barrel cleaning.

The M3 was OK, but not as good, its main problem being the cocking arm which was complex and tended to bend if any pressure was put on it; the hole in the bolt was a much better design. Also, its stock didn't have the mag loader.

Incidentally, the "grease gun" was the first gun to be made from two stamped halves welded together, and that is where Bill Ruger got the idea for making his .22 pistol that way.


January 23, 2011, 02:49 AM
I guess a few were made in 9mm Para as well.

James K
January 23, 2011, 12:07 PM
I am not sure any M3's were made in 9mm Para, but conversion kits were. They used STEN magazines with an adaptor. Supposedly they were for the French resistance, but I doubt they were ever used; all the pictures I have seen and information I have indicates the FFI got STEN's, BREN's, British revolvers and No. 4 or Mk III rifles, and those are the guns that show in liberation period pictures.


44 AMP
January 23, 2011, 12:33 PM
Another "experimental" item for the M3 was a curved barrel, for shooting around corners (or from inside a tank)! And, it worked! Only a handful made, and I doubt ever used in combat. M3 conversion kits were made in some numbers, it is a simple swap of barrel, bolt and mag. Again, like the Liberator pistol, they don't appear to have been used as intended, to arm the French Resistance.

The history of combat weapons is full of neat, interesting, and sometimes even practical designs that by the time they got produced, were never used because of changes in the war situation. Sometimes they fade into a few pages in books, and once in a while, they become the basis for post war development leading to the next generation.

The cocking system on the M3 is kind of wonky. It always made me think of a backwards grasshopper leg. And, when things go just right, in the wrong way, it can wind up jammed. The finger slot works much better, although it kind of put me off when I first saw it, when I actually got to use one, I found that it is easy, and it don't get any simpler. The springs on the grease gun are not very strong. They don't need to be. But there is a drawback to this, I already mentioned. A sharp jerk on the gun can cause the bolt to move back some, if the cover is open.

While it looks like a cheap piece of junk, the grease gun is actually a well thought out, effective weapon, within its range limitations. The M3A1 eliminated the few trouble spots the M3 had, except for that pesky tab on the barrel nut locking spring. Replacing that spring involves cutting off the old rivets and riveting on a new one. Not a tought job, but a pain nonetheless. It could have been designed better, but that would have made the gun a bit more complex. And, it doesn't happen all that often, really.

Mike Irwin
January 23, 2011, 02:17 PM
I've seen several 9mm conversion kits for the Grease Gun - museum holdings.

Only a few parts had to be changed.

I can't remember if the kit included a new bolt or not, but I think it would have to have given the difference in case head diameter.

Supposedly there was some consideration given to producing the Grease Gun in 7.62 Tokarev for the Russians via lend lease, but given that the Russians were doing quite well producing small arms, especially submachine guns, I doubt that they would have been interested.

January 23, 2011, 10:07 PM
I am not sure any M3's were made in 9mm Para, but conversion kits were.

I have seen at least one 9mm "grease gun" and even had a chance to buy it. A gentleman had it and a .45 grease gun in his table at a small gun show in Gainesville, FL, in 1965, during the halcyon days prior to the GCA of 68. They had both been dewatted by "plugging" the barrels with lead. I was offered the pair for the (then) princely sum of $100.00.

Apparently the 9mm was known as the "T20" (or some such), and, indeed, consisted of a replacement barrel, a lighter bolt and an adaptor to allow it to use Sten mags.

At any rate, I was a poor college student at the time and didn't 100 cents, much less 100 dollars, and, even then, I knew it was a no-no to reactivate the weapon without the tax stamp.:D

January 26, 2011, 10:43 PM
Amen. The M3A1 is one of my favorite SMGs. As Jim Keenan mentioned, the M3A1 is ingenious with its simplicity and the extra do-dads (integrated mag-assist-loader, cleaning rod fixture). Mags are super durable, but the feed lips will chew up your thumbs if you don't have a mag loader.

Such a fun firearm. If you get a chance to shoot one, do it.

January 27, 2011, 05:36 PM
Yesterday police in Newburgh NY [highest crime rate in NY state] caught a BG with a Sten gun !! That was a surprise ,you don't see many of those these days. The British SMG in WWII, reliable , durable and low cost to make.
Cost is significant during wartime and the M3 was much cheaper to make than the Thompson. Sheet metal parts can be made by any company that makes sheet metal propducts. A few years ago History Channel had an interesting film made by the Danish resistance .They were making SMGs in a toy factory right under the noses of the Germans !! :p