Three, two, one, sending!
Hey guys, thanks for tuning in to another video on ForgottenWeapons.com.
I'm Ian McCollum and we're out here today with a US M40 106 millimeter Recoilless Rifle.
This was really the ultimate evolution of the recoilless rifle in American military service.
So ... the first recoilless rifles were introduced right at the very end of World War II,
and actually saw substantial use in the Korean War. The problem was the gun that they had in the Korean War,
the recoilless rifle, was the M27. It was a 105 millimeter gun and it just had some problems.
It was rushed through development. The trunnions were badly placed.
It was way too heavy. They thought they needed more strength in the gun than they really did.
And all of this led to the redevelopment, or reassessment of how exactly this thing could be built.
Which led to the development of this, the M40 which was a much more successful gun.
This was used through Vietnam by the United States, and then it has been manufactured under license in a number of places around the world.
Exported fairly widely, and honestly it still sees combat use today in hot spots like the Middle East and northern Africa.
So the fundamental idea behind a recoilless rifle is that you give up the idea of
having an actual sealed chamber and instead you perforate the cartridge.
So you accept that when you fire, half of the energy is going to go to pushing
the projectile out of the front and the other half is going to go to just venting out the back.
It's not exactly 50/50, but you get the idea. And the reason to do this is you can save
a tremendous amount of weight by not trying to contain all of the pressure
and force it all to push the projectile out the barrel.
You get eight pounds of powder, which is what this uses. You can throw this thing - this is a 22 pound projectile -
downrange at about 500 meters per second. That's about 1650 feet per second.
And that's fast enough to be thoroughly effective in an anti-tank role with the right kind of warhead.
And then you can mount the whole thing in a package that weighs less than 500 pounds like this,
instead of having a multi-ton system. So this projectile is pretty much the same sort of thing
that would be fired out of an M60 tank, but it doesn't require a tank, it requires this
little under 500 pounds on a wheelbarrow mount.
As an interesting aside, one of the things that the guys who shoot this have to be very careful about is to ensure that these
projectiles weigh exactly the right amount, 22 pounds, because you have to balance the projectile weight with the powder charge.
So ... this is designed specifically to balance the amount of energy going out each end.
These projectiles are dummy ones originally that came hollow,
and so what they do is they fill the inside carefully with a mixture of lead and wax to get exactly the right weight in it.
So the way this actually works is very simple. This is just a breech-loading single shot gun.
First off, I will point out to you these big open voids in the back end.
That is where gas is going to vent when we fire the thing.
To open it, you push the handle down,
cycle it like so, and it's going to swing open.
We have a nice big extractor here that's going to pull the empty case out.
And that's about all there is to it. Four sets of locking threads.
So put your new cartridge in,
lock that all the way around. By the way, the cartridge has rifling pre-engraved on it.
So when you load the cartridge you rotate it just a little bit,
wiggle it around, make sure it lines up properly with the rifling in the barrel,
lock it closed and you're good to go.
One of the problems with the early M27 recoilless rifles is that
they weren't capable of getting a good enough rate of first round on target.
They weren't accurate enough in a practical sense, which isn't to say that mechanically they weren't accurate.
The problem was this doesn't have a very sophisticated sighting system and you only get one shot with it.
And the reason for that is because this is a recoilless rifle, you've got a tremendous
blast pattern coming out the back of the gun. And once you fire this thing
everybody anywhere remotely nearby knows that one's gone off, and they can see exactly where it fired.
So, what they did with the M40 is they came up with a system
to allow you to make sure that you had the gun on target. And unfortunately
we don't have that on this particular one, but that was the M8C which was a .50 caliber spotting rifle.
So it used a, not .50 Browning, but a shortened ... .50 caliber cartridge that was matched ballistically
to the 105 millimeter projectile of this.
By the way as a side note, 105 millimeter is the actual bore diameter.
This was named 106 so that its ammunition could be easily distinguished from the M27.
which used a slightly different cartridge case.
Anyway, with this guy you put it on target using your fairly simple little optical sight there,
and then you'd fire a round from the spotting gun, and that's just a single .50 caliber projectile.
It is by the way a semi-automatic magazine-fed .50, mounts up here.
... And I'll have a video on one of those when I find one.
But, you can fire that and they have an explosive spotter head on them so you can see where it hits,
and then adjust your aim as as you need until you're on target.
And then you can fire the main gun, get a first round hit,
and then get the heck out because everyone's gonna start shooting at your recoilless rifle.
The controls here are pretty simple. The gunner sits right here,
and he's going to use the scope here to aim. You have this as your traverse wheel,
both ways. And if you lift this up, then you can free swing the gun.
You have your elevation wheel here to elevate and depress the gun.
This is not a free float wheel, this is actually your trigger.
So when you pull this out, it fires the spotting rifle,. And when you push it in, it fires the main gun.
Don't get them mixed up.
The mount for this thing looks pretty goofy to be honest, but it's practical in a couple of ways.
So first off it is literally just a wheelbarrow carry sort of thing. This leg folds in towards that one,
you can pick this up and just move it around on that front caster wheel.
There ... are a couple of little hooks on these handles, and this fits into a Willys Jeep as well.
Or an M151 Jeep I think it was.
The Jeeps that are set up for these have a little divot that the wheel sits in, and then these two hooks
lock into the tailgate of the Jeep, lock it in place.
That was probably the most common way that these were used.
They were also mounted to a variety of other ... vehicles like the Mules.
There was ... basically a repurposed tank chassis called the Ontos that had six of these things mounted,
which is kind of cool and very very distinctive looking.
But the idea is that this whole thing is really quite light.
Just to point it out for the record, this thing on here is not typical on the guns,
and is most likely from this being used as a pressure test gun.
One little just interesting note here, when it comes to, you know, how simple and transportable and convenient this is.
The gun itself sits in this cradle, it just drops in and then this is a tension screw.
So all you have to do is loosen this, the gun picks right up out the top of the cradle for transportation or work.
All right, so let's actually try shooting it.
I do want to point out one very important safety factor with any recoilless rifle but especially this, the biggest of them.
Don't go anywhere near the back of one of these things. These have a huge back blast area.
And they will kill you at this end, as much as they will kill you at that end.
So always exercise extreme caution with recoilless rifles.
If you're around a recoilless rifle that's being fired in a civilian application,
be very sure that the person who has provided the ammunition understands what they're doing.
There is more complexity to recoilless rifle ammunition than there is to a lot of other types of large-caliber artillery ammunition.
So with that out of the way, let's see what happens.
Ready?
Fire in the hole.
Holy Sh
Three, two, one, fire in the hole.
Thanks for watching guys, hopefully you enjoyed the video. I'd like to give a big thanks to Hamilton & Sons Gunsmithing.
This is their recoilless rifle and they were generous enough to give me a chance to film it for you guys.
Thanks for watching.
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