.204 Ruger

.204 Ruger
204 Ruger 32 grain (2.1 g) Vmax, 223 Remington 55 grain (3.6 g) Vmax, 204 Ruger 40 grain (2.6 g) Vmax.
Type	Rifle
Place of origin	USA
Production history
Designer	Ruger/Hornady
Designed	2004
Produced	2004–Present
Specifications
Parent case	.222 Remington Magnum
Case type	Rimless, bottleneck
Bullet diameter	.204 in (5.2 mm)
Neck diameter	.2311 in (5.87 mm)
Shoulder diameter	.252 in (6.4 mm)
Base diameter	.3764 in (9.56 mm)
Rim diameter	.378 in (9.6 mm)
Rim thickness	.0449 in (1.14 mm)
Case length	1.850 in (47.0 mm)
Overall length	2.2598 in (57.40 mm)
Rifling twist	1-12
Primer type	small rifle
Ballistic performance
Bullet weight/type	Velocity	Energy
32 gr (2.1 g) BT	4,225 ft/s (1,288 m/s)	1,268 ft·lbf (1,719 J)
40 gr (2.6 g) BT	3,900 ft/s (1,200 m/s)	1,351 ft·lbf (1,832 J)
45 gr (2.9 g) SP	3,625 ft/s (1,105 m/s)	1,313 ft·lbf (1,780 J)
Source(s): Hornady [1]

The .204 Ruger is a centerfire rifle cartridge developed by Hornady and Ruger. At the time of its introduction in 2004, the .204 Ruger was the highest velocity commercially produced ammunition, and the only cartridge produced commercially for bullets of .204 inch/5 mm caliber.

Characteristics

The 204 Ruger was developed from the .222 Remington Magnum, which has the second largest case capacity in the family that began with the .222 Remington. Only the European 5.6x50 Magnum is larger, which itself is a lengthened version of the 222 Remington Magnum. The 222 Rem Mag provides about 5% more usable (below the neck) case capacity than the most popular member of the family, the NATO 5.56×45 mm (.223 Remington). To make the 204 Ruger, the 222 Rem Mag case was necked down to .204 inches (5 mm) and shoulder moved forward and angle changed. Bullets available in .204 caliber range from 26 to 50 grains (1.7 to 3.25g), and although the selection is limited, it is growing as the cartridge gains wider acceptance. The Hornady factory load is listed at 4,225 ft/s (1288 m/s) with a 32-grain (2.1 g) bullet. To achieve these velocities, the factory uses a proprietary powder composition known internally as SMP746, specially formulated by Primex, and not currently (2010) available to handloaders. The propellant features a de-coppering agent that helps prevent fouling. Reloading data from Hornady, using commercially available powders, indicate velocity peaking at just under 4,200 ft/s (1,300 m/s) with the 32-grain (2.1 g) bullet in longer barrels. Many AR-15 rifle manufacturers, including Remington, now offer the .204 Ruger as an alternative chambering alongside the usual 5.56x45/.223 Rem.

Development

The .204 Ruger was the second Ruger-named cartridge produced by a partnership between Ruger and Hornady, the first being the big bore .480 Ruger revolver cartridge, introduced in 2003 for the Super Redhawk. With the backing of a major gunmaker and a major ammunition company, the round was an instant success, with other ammunition makers and firearms makers quickly producing offerings in the new caliber. Ruger's initial offerings included the bolt action Model 77 MKII, and the single shot Ruger No. 1, and Hornady offered loadings with 30-and-40-grain (1.9 and 2.6 g) bullets.

The .204 Ruger has proven to be a very accurate and efficient cartridge: an early tester reported 1/2 MOA groups at 100 yards (91 m) with the Hornady loads and a Ruger #1 Varmint rifle. This is not surprising, considering that the first cartridge in the family, the .222 Remington, was a top benchrest shooting cartridge for many years after its introduction.

The .204 Ruger was intended primarily for varmint rifles, which require bullets with flat trajectories but not much mass or kinetic energy. The .20 was "splitting the difference" between the popular .22 varmint rounds such as the .220 Swift and .22-250 Remington, and the tiny .17 caliber rounds such as the .17 Remington and the .17 HMR. The resulting cartridge provides somewhat higher velocities than any of these, giving a maximum point blank range of more than 270 yards (250 m).

Velocity

Ruger's claim to being the velocity king with the .204 was based on two points. First, other 4000+ ft/s cartridges were wildcats, not commercially produced; the 5mm/35 SMc, for example, can reach 4,800 ft/s (1,500 m/s) using a 30-grain (1.9 g) bullet. Although the SMc cases prove to be almost impossible to form and dies both forming and reloading are extremely expensive to obtain.

Second, the ammunition used to achieve the 4200+ ft/s was only available from Hornady using a special powder not available to the general public.^[2] Handloaders typically achieve velocities more in the area of 4,050 ft/s (1,230 m/s) using a 32-grain (2.1 g) bullet.^[3] Note that handloads using a 40-grain (2.6 g) bullet in other commercial cartridges such as the .220 Swift and .223 WSSM also achieve similar velocities to the .204 Ruger. The advantage of the .20 caliber .204 is that it achieves these velocities using less powder, less recoil, less heat, and better air resistance than the heavier cartridges. The 204 Ruger has a maximum range of approximately 500 yards (460 m).

• Ballistics Chart By Hornady

See also

• 5mm/35 SMc
• List of rifle cartridges
• 5 mm caliber

References

External links

• .204 Ruger info at Hornady website
• Sturm, Ruger & Co., Inc.