It’s time for another head to head. Let’s look at two extremely popular light(ish) antitank weapons.1 In the blue corner, fighting out of Sweeden, is the Carl Gustav Recoilless Rifle. And in the red corner, fighting out of Russia, is the RPG-7. Let’s dig a little deeper into these two weapons and see what we think of them.
The Carl Gustav was designed just after the Second World War. It’s a recoilless rifle, which means it’s got a rifled barrel and it vents propellant gasses backward to counteract the recoil of the round. This recoilless principle allows for a relatively high projectile velocity of 230-290 m/s. This is twice as fast as an RPG-7 rocket, and allows the Carl Gustav to have a longer effective range against fixed targets. Available rounds include: HE, HEDP, HEAT, tandem-HEAT, illumination, smoke, programmable airburst, and flechette. Variants are available (currently for HEAT rounds) with rocket assist for a little more range, or backblast-reduction to allow use in confined spaces, like from within a building. HEAT rounds are rated for penetration of 400 mm of ERA; the Tandem-HEAT version is rated for 500 mm (plus neutralization of some ERA). This is not going to scare a modern tank unless you hit it from the side. It’s more than adequate for older tanks, or for lighter armored vehicles.2 The Carl Gustav has a caliber of 84mm, and of course, all weapons fired must fit in the tube. Since a reasonable first-order approximation of the effectiveness of a shaped charge is its diameter,3 this puts a pretty strong limitation on how much armor you can punch through.4 The standard version of the Carl Gustav is known to the US DoD as the M3 Carl Gustav, which weighs about 19 lbs empty. There’s also a shorter, lighter version, the M4 Carl Gustav, which weighs about 15 lbs empty.
The RPG-7 is somewhat newer, dating back to 1961. Interestingly, the tube is only 40mm, because it holds only the rocket motor. The warhead is fatter than the tube in most cases. This looks kinda goofy, and contributes to the weapon’s relatively poor accuracy at range, since the round is less stable. On the other hand, it means we remove a significant constraint on our warhead design. So while it will turn into the wind, which isn’t what you’d expect, we can fit some really big things onto the RPG-7 without issue. These include the tandem-HEAT PG-7VR rocket, which is rated for up to 750mm of RHA penetration. That’s actually starting to get dangerous for modern MBTs, though it’s still generally considered inadequate for the latest types5. This is a 9.9 lb. rocket, because you can’t cheat physics. Oh well–it means your light antitank weapon still has some bite in it if you happen upon things with treads. Lighter, older, HEAT rockets are also available, as is a fragmetation warhead rocket and a thermobaric warhead rocket. Finally, there’s an interesting bunker-clearing warhead that combines an explosively-formed penetrator with a follow up fragmentation warhead. Weight of the RPG-7 in basic form matches the lightened M4 Carl Gustav at 15 lbs or so. There’s also a Chinese copy, the Type 69, which cuts weight to 12.3 kg. And, if you actually want to apply modern materials to the design, there’s a US company, Airtronic, that’s made a clone called the Mk 777, which weighs only 7.77 lbs, or 3.5 kg.
So let’s break it down. The Carl Gustav has much better range. The RPG-7 (and it’s clones) are much lighter. The Carl Gustav has available Airburst rounds. The RPG-7 has available thermobaric rounds, which could be made for the Carl Gustav, but are unlikely because someone’s likely squeamish. The RPG-7 also has a tandem HEAT warhead that’s still decently formidable, and that’s not likely a capability to come to the Carl Gustav anytime soon. The Carl Gustav has rounds designed to accommodate confined-space operation, but the RPG-7 does not.
What’s our pick? This may shock you, but we prefer the RPG-7. We like theromobarics. We like having a light AT weapon that still has some AT punch left in it. And we like the lighter weight, especially if you’re going to take it on a long patrol. The Carl Gustav isn’t a bad choice by any means, but it’s a little outclassed by it’s Soviet competitor. Now, if range became a bigger issue, like in Afghanistan, then the Carl Gustav becomes worth its weight. But I think Afghanistan is an outlier.
For mechanized troops, for whom the weight is less of an issue, we still really, really like the Panzerfaust 3, since that has a proper antitank warhead on it.
1.) I’m looking at things that can be operated by a single person, and aren’t guided. Interestingly, guided weapon shootouts are a lot less fun to write, because the winner is much more obvious.
2.) This is actually true for the vast majority of light antitank weapons. There are a few (that really stretch the definition of ‘light’), including the Panzerfaust 3 which I wrote about here.
3.) At least, for similar generation designs. Also, I said ‘first order’ so some roughness is implied.
4.) You’ll notice modern weapons that actually are rated to defeat modern armor are significantly bigger in diameter than 84mm.
5.) This was about the armor penetration rating of the standard Panzerfaust 3 rocket. It has since been replaced by an improved model with a more powerful warhead for the antitank role.