Hi guys, thanks for tuning in to another video on ForgottenWeapons.com.
I'm Ian McCollum, and I'm here today at Movie Armaments Group
up in Toronto taking a look at
basically, the first issued US under-barrel grenade launcher.
This is a Colt XM-148, and this is really an outgrowth of
Project SPIW, or Special Purpose Infantry Weapon.
That had been a project to increase the lethality of infantry firearms and it did this in two ways.
They were hoping to increase hit probabilities with ... what they called the point target system, namely like "the bullets".
And they did that with things like multi-shot burst firing, and flechettes, and all sorts of stuff.
At the same time they also wanted to give the standard infantry weapon what they called an area effect weapon,
an area effect component. Which is to say a grenade launcher attached to the standard rifle.
And while Project SPIW was really having trouble coming up with anything practical and effective,
it became obvious that the grenade launching component was something that could be spun off and adapted to other rifles.
And so in 1963 the first request went out for an under-barrel grenade launcher to go on the then very early M16 rifles.
Now there were originally three different variations of this that were tested by the military.
One of them was by Colt, which is what became the XM-148 here.
It was originally called the CGL-4, almost certainly Colt Grenade Launcher,
and the 4 probably stands for 40mm because that's the size of the grenade.
There was one, by Ford actually, which had been partnered with, or coupled with, the Springfield Armory SPIW guns.
And then the third one was produced by AAI.
And the Ford gun was considered just technologically not satisfactory.
The AAI gun used a non-standard cartridge. It actually had this rather clever system where,
basically, the rifled section of the barrel was incorporated into the actual cartridge case,
making the whole thing disposable, which substantially lightened the grenade launcher
element that had to be bolted onto the gun. It was a really interesting project.
Someday we'll get our hands on one of those, we'll bring that to you as a separate video.
But the one that actually progressed in US military testing was the Colt, the CGL-4.
Now this project actually progressed pretty quickly.
It was developed in '64. In '65 Colt got the first contract for 30 test ... launchers.
Those came in they started ... doing trials on them, and they discovered actually they had
problems cracking the aluminium body of the launcher.
So Colt took those back, they re-engineered the alloy and the design a bit,
fixed all of the test ones, sent them back for more testing. At that point they seemed pretty good.
And this sort of weapon was something that guys really wanted to be able to deploy in Vietnam quickly.
... I'm sorry, in '66 they got the first order, first major contract, for 10,500 of these launchers.
First deliveries were in December of '66. By ... January of '67 they had delivered more than 10,000 of them.
By the summer of '67 they had delivered something like 27,400 of these XM-148 launchers.
So, let's go ahead and take a look at how it works,
and then we'll talk about why you don't still see XM-148s around today.
These were made by Colts in Hartford, and so they're marked that way on the left side.
And we've got the other designations on the right side,
Launcher, Grenade 40 millimeter XM-148, a serial number and a US property mark.
The fundamental operating mechanism of this is pretty similar to the M203 that would come later,
in that the barrel slides forward to load a cartridge.
So to do that you push in this button, you then actually tilt the grip forward,
that unlocks it, and you can then slide the barrel forward.
Once it's all the way forward your firing chamber is open under here and then you can take your grenade (this is a dummy grenade),
drop it in there, slide ...
the barrel back over it. Now the thing is loaded, now you have to cock it.
This swiveling handle here is the cocking handle.
This is one of the complaints that troops would have because the cocking force on this is 30 pounds, or about 14 kilograms.
It's really a pretty stiff lever to cock. So once that's cocked, then you have a trigger here.
There is also a safety switch on the bottom of the launcher.
So moved over to the right, on the inside, it's set to safe and can't fire.
Flipping this out to the outside (you can see the F now), that's in the firing position.
And to fire it you simply use your trigger finger, not on the rifle trigger, but down here.
Click, and that fires your grenade.
Now it's kind of interesting to me to read that apparently, well, a lot of guys didn't like this thing because
and I think for pretty obvious understandable reasons, this is really just asking to cause problems.
So this gets snagged on stuff when you're moving through the jungle.
It's possible to get twigs or other debris jammed in between this bar and the rifle receiver and cause problems.
And when you do pull this what you're actually doing is tripping this lever right down here.
So apparently what a lot of guys liked to do is actually just fire it by pushing this in.
Which works just fine, boom, fires like that.
Naturally, you need some sort of sight on the grenade launcher for actually aiming the thing.
And the sight that Colt came up with is bolted out here on the left side of the gun.
This was also a source of complaints that this would also snag on stuff and get in the way.
It is zeroed out to 400 metres, or 400 yards.
And you can just click this around.
However, unfortunately Colt screwed up and when they manufactured these they calibrated this wrong.
So they actually had to go back and fix them before you could really shoot the thing accurately,
because the range markings weren't proper for the actual grenades being fired.
The sights themselves are a post and aperture type. You can rotate the front post.
You can also rotate the rear aperture to adjust your zero.
And lastly Colt came up with a new sheet metal handguard to go on the rifles that were equipped with the XM-148s
because you've got a couple of mounting pillars in here, and obviously this won't fit with the standard handguard.
So that is the mechanical setup of the XM-148.
I mentioned that by the summer of '67
more than 27,000 of these launchers had been purchased and delivered to the US military.
Well in May of '67 the XM-148 was deemed unsuitable for field use in Vietnam
and basically the whole project was scrapped. There were a couple major problems with them.
One of them was the cocking and the trigger levers tended to snag on brush.
The cocking handle, the cocking force, was far too strong. Guys really didn't like that.
The whole trigger mechanism was overly complex, it was difficult to maintain and repair in the field.
And just in general this really didn't provide a substantial improvement over the M79 grenade launchers.
So in light of all of these problems the project was scrapped.
Everyone still thought that the concept held a lot of merit, that the US should figure out some way
to have an under-barrel grenade launcher so that your rifle squad grenadiers still had a rifle to shoot.
But it would have to be a different design than Colts. So this would of course lead ultimately to the M203,
which we will talk about in a separate video.
And yeah, there's some irony involved in the production of those too, but we'll get to that in a later video.
So I actually have an M203 here that we'll be filming after this.
Anyway, hopefully you guys enjoyed the video. I'd like to give a big thanks to Movie Armaments Group
for letting me take a look at their awesome early and completely intact XM-148.
Thanks for watching.