Specifically, the path of "crossing" of the gun and the gun went in the 50s of the last century South American designer David Dardik. He took a revolver from the main part — the drum, and from pistols — shop. Interface them was quite difficult. But fortune promised huge prospects. The fact that the chambers are drums more detail in terms of the usual feeding of cartridges than the movable shutter autoloading pistol. But it was necessary to come up with a good and reliable method of feeding of cartridges in the bolt and eject spent cartridges. The forward chambering a cartridge from the magazine into the drum was immediately recognized by more than unprofitable system. She almost did not give benefits, but significantly complicates and increases the cost of construction. By the mid-'50s Dardik came to the idea of open Camore. This means that instead of the tube through openings in the drum should be made U-shaped grooves. In this case fails to be fed from the cartridge magazine specifically the bolt, which in turn is aligned with the drum barrel. Extraction sleeves for all that would occur under his her weight.
You can say what specific forms of these chambers and are a major invention Dardika around which were built following all the development. But the U-shaped Camore prevents the use of the standard cartridge-ring. Due to the shape of the cavity in the drum cartridge is not firmly fixed, that is guaranteed to lead to misfires and incorrect mounting position when descending hammer. Turn away from a promising delivery system cartridge Dardik not want to because I had to go on affirmative action. The output was the development of a new special cartridge, and then received the title Tround. The first version of such holder had a specific asymmetric shape that allowed him to sit tight in the bolt. The efficiency of feed cartridges were tested. At the same time, there was another poll, asymmetrical patron sought sophisticated store design that would seek it in the right way before the "boot" in the bolt. In the end, the middle of 1958 Dardik has made the latest version of the cartridge. Its cross section is now to be symmetric, and appeared in some semblance of a triangle Reuleaux. New drum was also made with similar chambers. The symmetrical design of new cartridges were the least demanding of the supply system. It is interesting that the design of the cartridge is allowed to use the same sleeve length 57 mm ammunition of different calibers. In the end, it was deployed creation of 3 types of cartridges .226 caliber (5.56 mm), .30 (7.62 mm) and .380 (9 mm). In duralumin, and later a plastic sleeve is pressed powder, inserted the bullet and primer.
In addition to the entire line of cartridges company Dardick Corporation by the end of the 50's has launched small-scale creation of a new cartridge pistols. On their own design, they are in some measure resembled revolvers double act. That is, when you press the trigger drum with 3 triangular chamber rotates at a third of the total turnover, and the hammer is cocked and down. With all this while turning right is ejected cartridge cases from just shot the bolt and feed a new cartridge into the empty the bolt. Pistol ammunition supply was made from a built-in pen shop for 11 rounds. Because the store was integrally to its equipment to the gun accompanied clip. With its help, either manually cartridges inserted through a special box with lid.
Since, unlike revolvers, design Dardika had open chambers, it was necessary to predict the detail that would be delayed Traund Insert from falling out at all stages of the drum. For this reason, around the drum gun had a cylindrical casing with an opening for the extraction cartridges. In the upper part of the drum cover plate was further strengthened frame pistol. This bar, along with a drum and played the role of the chamber / chambers with the shot. Due to load the upper part of the case cast strip. The very same frame was manufactured by stamping in the form of 2-parts combine to form a hollow body. For ease of use on the sides of the pen is plastic cheeks, and sights were the most ordinary open sights. Also on the front and rear sights were made white point for the convenience of sight.
Since all the bullets had a sleeve of similar size, the opportunity to make several types of guns that are based not only on the same principle, and on the same mechanics. There were three versions of the manufactured instruments with cartridges "Traund":
— Dardick Mod 1100. This gun barrel was equipped with 9 mm caliber. Trunk was fixed and did not have the ability to remove. Barrel Length — 3 inches (76.2 mm);
— Dardick Mod 1500. At first, this version of the gun was produced with the store for 11 rounds, but later its capacity increment to 15. With all of this from the very beginning was done two versions of trunks: a length of 4 inches (102 mm) and the other — 6 inches (152 mm). Regardless of the length of the barrel in the kit to the proposed two-barrel pistol caliber 9 mm and 5.56. Removable barrel mounted on a special latch and its substitution required only a couple of minutes. Barrel removal given the opportunity to make the Model 1500 a special "accessory", which has in its composition butt, long barrel and fore-end. He "turned" gun in a light rifle. 20-inch extra barrel produced could in 5.56, 7.62 and 9 mm;
— Dardick Mod 2000. Pistol with a magazine for 20 rounds (pen had a particularly large size) and 6-inch barrel. Were available to the customer all produced calibers, barrel also in conjunction with the butt.
The entire line of guns designer David Dardika was a very, very unique method of solving problems has long been overdue. Indeed, the universal sleeve Traund-holder, whose size is not depending on the caliber, is permitted to make of the 1st set of a gun, adapts to the requirements of a particular hand. But the gun was quite expensive. So, Mod 1500 a 60-year cost a bit less 100 U.S. dollars. Most of the revolvers conventional design at that time was worth 20-30 bucks cheaper. Vpribavok to this ammo pack (10 pieces) cost as much as 15 bucks. Relatively high price of the instrument with a simple way to put the future of pistols ammunition Dardick question. In turn, the novelty of the design and absolutely brand new system scared off potential buyers. Because of this, only four years after the
start of production — in 1962 — a small factory Dardika closed. For so short-lived period was made less than fifty guns of various modifications, including seasoned standards. Because of the weight of financial problems D. Dardik was obliged not only to close his company, and realize all its assets to repay debt. A certain amount of detail undone Dardick pistols falling into the hands of Numrich Arms, which gathered some of their guns. Of the production of these guns was not running. At the current time Dardika guns are registered collector's, which sometimes occurs at the auctions.
After a decade after the close of Dardick Corporation to the ideas of the triangular cartridge and open the bolt back constructors firm Harrington & Richardson. On competition Pentagon SPIW (Special Purpose Individual Weapon — Special target private gun), the company introduced a set of "machine-cartridge" in the base of which was cartridge, reminiscent Tround. However, instead of a bullet H & R managed to fit in as much as it swept with three feathers. In the development of machine H & R SPIW an active role perceived that David Dardik. But the machine-based Traund-holder was not destined to reach implementation. He was not even allowed to test. The customer felt that instrument, in which the shooter is protected from the hot propellant gases only plastic sleeve, applicable even for a role in the trials. Since the topic of open chambers nobody seriously vorachivalsya.
According to the materials of websites: