Looking at other Dardick patents I got remainded on the space gun.
Does anybody know how far this got in reality?

Also interesting to see there was a recoilless variant patented.

And last but not least the last patent I saw was by 3 Dardicks (sons?) dated as late as 2014!

Here the patent on the drill gun:
US4004642_drill.pdf (917.0 KB)


I picked up one of those .50 calibre Trounds at the Bisley meeting about 25 years ago. I don’t know if this is useful additional info or a red herring, but the guy I got it from went into a detailed story about it being part of a trial for a Royal Navy rapid fire ant-missile shipping defence gun. He claimed the trial wasn’t a success as the cyclic rate was that high that the plastic casings had a tendency to melt and caused stoppages?! Pete.


Pete, there is similar stories about firing pins if I remember correctly. This is one of the reasons I am looking forward to Mel’s book.



Yes we got ours at the same time, the guy selling was Chris Lewis, the last proof master at the Kynoch factory.

I bought a number of them I have sold over the years, I only kept the one for my collection.

I hadn’t heard the bit about the Royal Navy, I had assumed it was for our American cousins. But he did tell me that it wasn’t a success for technical reasons.




Thanks, yes I had heard that they were ceramic bullets used for drilling, but I dont think it was a success.



Has Pepper got one of these drills. Utility cartridge like this I would think to right in his interests.


EOD; Yes, I have interviewed David Dardick’s son Steve, who was the Tround International, Inc. plant manager and a lot more. Steve has two sons and the three of them are keeping the open chamber concept alive, although inactive for the time being. The family is very supportive of my book project and are helping a lot. Through them, I’ve been able to get much firsthand information, documents, photos, etc.

On the Cal. 50 Trounds for a U.S. Navy R&D contract, I don’t have any hard info (yet, but I will) about the white plastic caps, but I’m sure the rounds were not fired with those in place. The front cap bulges out a bit, slightly increasing the OAL, which would not work. And the plastic would jam up the gun’s action. One of my .50s has the white caps on both the front and rear over the primer. I have 22 variations of these and none has an electric primer, so the rear caps must not be to protect against stray electricity. Dardick did have a contract with the Brits, so it’s not surprising that a few of the .50s should show up there.

Dardick’s hard-rock-drilling system, a.k.a. “Terra-Drill,” with its triplex cartridges is very interesting. I grew up in East Texas in the middle of oil refineries and oil wells and picked up a little knowledge about them without really trying. Drilling oil wells costs a ton of money, and time is money. When drill bits wear out, the entire stack has to be pulled out so the bottom piece with the drill bit can be changed. This takes a lot of time and the drill bits are very expensive.

Dardick’s idea was to increase the life of the drill bit by 10 times and increase the speed of the drilling in hard rock, e.g., Taconite, significantly. He designed a system with a 5,000-round magazine of triplex Trounds. When the drill bit encountered hard rock, the system began firing the Trounds, each with three ceramic projectiles in clear sabots. The projectiles were ceramic so the drill could pick up their shattered remains along with the other rock it was drilling through. Metal projectiles would have jammed up the drill.The projectiles were loaded at a slight angle away from center in the Tround cartridges for the correct dispersion and the gun barrels were set at the same angle. They came out of the barrels at 4,500 fps, impacted the hard rock at slightly different times, shattered, and set up shock waves that fractured the hard rock up to a depth of 20 inches or so, depending. This allowed the drill bit to drill through pre-fractured hard rock and a higher rate and with less wear. Details will be in the book.

Here’s a pic of a clear Lexan cartridge dummy. Note the divergent angle of the three ceramic projectiles. I just weighed one at 46 grains, but there are variations. The one I just measured has a diameter of 0.2420 inch and an OAL of 1.2350 inches.

Here are three other pics of the Dardick Tround system. The first is the Dardick drill bit group with one of the three barrels easy to see.

The second pic shows the assembly in an Ingersoll Rand T-4 rig:

And the final one shows the Dardick Tround “Terra-Drill” being unloaded from a flat-bed 18 wheeler.

I’m really just at the beginning of this and will have a lot more detailed information in the book.


Mel - I don’t collect Dardick rounds except the adaptors that take auto pistol cartridges, but when it is out, I want a copy of your book! I think it will be an absolute must for anyone with a passion for ammunition, regardless if they collect in this field or not!

John Moss


Like John, I only collect the 9mm Dardick adaptors, and I have the three colors shown below. Interestingly, my mustard-green adaptor has the exact same 9mm cartridge in it as does Mel’s.


As I mentioned in another topic I have been trying to sort out my storeroom in the process I found a Dardick booklet that has a bit of mouse nibble but thought may be interesting.

Dardick Pamplet.pdf (449.5 KB)



Mel, thanks for the insight.
Any preview you maybe can give us on the space gun project?

Lew, here the patent for the adaptor case design:
US3568599_adaptor.pdf (850.9 KB)


Here is a page from an early brochure showing the Series 2000 pistol made for aluminum cased trounds:


Forgot, Mel, it seems if there is one knowing the answer now it will be you.
Anything you can say about this:


Photos of the 3 Dardick 45 acp rounds I have in my collection.
ECS 43 headstamps.
Steel cases.
Dardick%2045%20acp%20a Dardick%2045%20acp%20b Dardick%2045%20acp%20c Dardick%2045%20acp


Are these adaptors meant to be reloadable?


EOD; Yes, all Dardick Tround adapters were meant to be reloadable. I think the reason for the mixed U.S. and foreign WWII-era cartridges loaded in the adapters shown on this thread is simply that they were readily available and cheaper than then-current cartridges. Dardick started work on his Trounds in the late 1950s, and the first factory and corporate headquarters was opened in Hamden, CT, on 21 May 1959. Back then, 60 years ago, surplus military ammunition was cheap and there were tons of it available.

You asked about the Tround space gun. As part of the workup of the Strategic Defense Initiative (SDI), a.k.a. “Star Wars” began by President Reagan in 1983, commercial vendors developed proposals for their systems to destroy incoming Soviet missiles/warheads. MBA’s system used high-velocity Swarmjets to do the job and they are covered in my Gyrojet book. Dardick’s system used a 720-barrel (yes, that’s right; 720 barrels) gun mounted in an orbiting satellite to destroy incoming missile warheads with high-velocity pellets. Tround cartridges had 50 pellets per round. When the gun fired, a cloud of pellets several hundred feet in diameter and 4,000 feet long was formed and it traveled toward its target at 29,000 feet per second. The incoming warheads were traveling at about 50,000 fps. The gun fired thousands of rounds per second. There will be lot more information in the book, but that’s a basic intro. Here’s a pic of the gun.


Mel, this looks incredible!!! Thank you!

What was the caliber of the gun?

29,000 fps Vo + 50.000 fps target speed means an impact speed of 79,000 fps (at best)! For us Europeans this makes more than 24,000 m/s!!! This is beyond imagination! So as a matter of fact light and “cheap” projectiles/pellets would do I understand.
And “pellets” means flat discs or cylinders? What was the pellet material?

Now I am even more curious, what is the time plan for your new publication?


EOD; Please be patient. My research is just beginning on this and lots of other strange Dardick guns and ammo. Remember that MBA used light aluminum hemispherical-nose Gyrojets to do the same thing in space. See page 122 of the Gyrojet book. Something small and light can do a lot of damage given a high enough velocity, and there’s no aerodynamic drag in space. Orbital velocity is about 17,000 statue miles per hour at a typical altitude divided by 60 = 283 miles per minute divided by 60 = 4.7 miles per second times 5,280 feet per mile = 24,903 feet per second with the orbiter and gun just “sitting still.”

One of MBA’s NASA contracts was for a hypervelocity gun that would achieve a velocity of 100,000 feet per second to simulate micrometeorites that might damage a spacecraft. During the R&D, MBA actually achieved a velocity of 32,800 feet per second, on Earth, in a partial vacuum.

And the missile/warhead is coming at the gun, so its velocity is added to the mix. Pretty fast, so a small projectile with little mass will do a lot of damage. Did you see “Gravity?”


Mel, I did not mean to rush you or so, sorry.

I think I do get along with the math and physical conditions in space (drag, speeds etc.)
I did not watch Gravity as I am no real TV or cinema person. But as you imply effect of high speed particles in space is devastating. I been looking into aircraft and space armament in the past and also have a special interest in the Russian space gun project.

Good to see you have decided on another subject where development and projected use were extraordinarily special.
Really looking forward to your book and hardly can wait for it.


Interesing that I jsut read this on IAA last week, sorry if I am duplicating a reply by someone else.

20mm Tround PGU-28 Projectile from July 15!

I have a friend who collects Dardicks’, and also has a boatload of ammo of various sorts and sizes.
I sent him a query, and will PM you with his contact info if he says it is O.K.

Mel, PM sent with contact info.


What happened to the spent cases when the drill was down in the well? Were they stored inside for later removal?

Was there a specific reason that the Terra-Drill system never entered regular use?