.204 Ruger

Infobox Firearm Cartridge
name= .204 Ruger


caption= 204 Ruger 32 grain (2.1 g) Vmax, 223 Remington 55 grain (3.6 g) Vmax, 204 Ruger 40 grain (2.6 g) Vmax.
origin= USA
type= Rifle
designer= Ruger/Hornady
design_date= 2004
manufacturer=
production_date= 2004-Present
number=
variants=
is_SI_specs=
parent= .222 Remington Magnum
case type=Rimless, bottleneck
bullet=.204
neck=.2311
shoulder=.252
base=.3764
rim_dia=.378
rim_thick=.0449
case_length=1.850
length=2.2598
rifling=1-12
primer=small rifle
is_SI_ballistics=
bw1=32
btype1=BT
vel1=4225
en1=1268
bw2=40
btype2=BT
vel2=3900
en2=1351
bw3=45
btype3=SP
vel3=3625
en3=1313
bw4=
btype4=
vel4=
en4=
bw5=
btype5=
vel5=
en5=
test_barrel_length=
balsrc= Hornady [http://www.hornady.com/images/ballistics/ballistics_charts.pdf Hornady] ] The .204 Ruger is a centerfire rifle cartridge developed in 2004 by Hornady and Ruger. At the time of its introduction, the .204 Ruger was the highest velocity commercially produced cartridge when loaded with factory ammunition, and the only cartridge produced commercially for bullets of .20 inch/5 mm caliber.

Characteristics

The .204 Ruger was developed from the .222 Remington Magnum, which has the largest case capacity in the family that began with the .222 Remington. The .222 Rem. Mag. provides about 10% more case capacity than the most popular member of the family, the NATO 5.56x45 mm (.223 Rem). To make the .204, the .222 Rem. Mag. was necked down to .204 inches (5 mm). Bullets available in .20 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 popularity. The Hornady factory load is listed at 4,225 ft/s (1288 m/s) with a convert|32|gr|sing=on bullet. To achieve these velocities, the factory uses a proprietary powder composition specially formulated for the .204 Ruger, and not currently (2007) available to handloaders. Reloading data from Hornady, using commercially available powders, indicates velocity peaking at just under convert|4200|ft/s|m/s|abbr=on with the convert|32|gr|sing=on bullet.Many AR-15 rifle manufacturers, including Remington, now offer .204 Ruger as an alternative chambering alongside the usual 5.56mm/.223.

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 #1, and Hornady offered loadings with 32 and convert|40|gr|sing=on bullets.

The .204 Ruger is proving 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 (248 m).

Velocity

Ruger's claim to velocity king with the .204 was based on two points. First, that other 4000+ fps cartridges were wildcats, not commercially produced; the 5mm/35 SMc, for example, can reach convert|4800|ft/s|m/s|abbr=on using a convert|30|gr|sing=on bullet.

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 [http://www.chuckhawks.com/204_ruger.htm .204 Ruger by Chuck Hawks] ] . Handloaders typically achieve velocities more in the area of convert|4050|ft/s|m/s|abbr=on using a convert|32|gr|sing=on bullet. [http://data.hodgdon.com/cartridge_load.asp .204 load data at Hodgdon] ] . Note that handloads using a convert|40|gr|sing=on 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, and less heat than the heavier cartridges. The 204 Ruger has a maximum range of approximately 500 yards

One of the down-sides to firing bullets at such velocities is short barrel life. Generally speaking, extremely fast bullets tend to wear out a barrel significantly sooner than slower ones. The high pressures, temperatures, and friction can quickly wear away portions of the throat and rifling. This erosion results in deteriorating accuracy. The amount of erosion and time it takes to negatively affect accuracy is based on things like temperature [ [http://www.superiorballistics.com/barrel_heating/comparative_barrel_heating,_smc_vs_conventional.htm Barrel Heating at Superior ballistics] ] , bore-size, velocity, etc. This effect is common to all small arms cartridges that approach or exceed muzzle velocities of convert|4000|ft/s|m/s|abbr=on, including the .17 Remington, .220 Swift, and .22-250 Remington.

ee also

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

References

* [http://www.6mmbr.com/cartridgediagrams.html Cartridge Dimensions] from 6mmBR.com
* [http://www.findarticles.com/p/articles/mi_m0BQY/is_10_50/ai_n6180938 Guns Magazine, 2004]
* [http://www.gunblast.com/Ruger204.htm GunBlast.com] , May 2004

External links

* [http://www.hornady.com/story.php?s=54 .204 Ruger info] at Hornady website
* [http://www.ruger-firearms.com/ Sturm, Ruger & Co., Inc.]
* [http://www.204ruger.com 204 Ruger info] at www.204ruger.com