| 7-30 Waters | ||
|---|---|---|
| Type | Rifle and single shot handgun | |
| Place of origin | United States | |
| Production history | ||
| Designer | Ken Waters | |
| Designed | 1976 | |
| Produced | 1984 | |
| Specifications | ||
| Parent case | .30-30 Winchester | |
| Case type | Rimmed | |
| Bullet diameter | .284" (7 mm) | |
| Neck diameter | .306 in (7.8 mm) | |
| Base diameter | .422 in (10.7 mm) | |
| Rim diameter | .506 in (12.9 mm) | |
| Rim thickness | .058 in (1.5 mm) | |
| Case length | 2.04 in (52 mm) | |
| Overall length | 2.52 in (64 mm) | |
| Primer type | Large Rifle | |
| Maximum CUP | 40,000 CUP | |
| Ballistic performance | ||
| Bullet weight/type | Velocity | Energy |
| 120 gr (7.8 g) Nosler Partition FP | 2,700 ft/s (820 m/s) | 1,940 ft·lbf (2,630 J) |
| 139 gr (9.0 g) Flat point | 2,540 ft/s (770 m/s) | 1,990 ft·lbf (2,700 J) |
| 154 gr (10.0 g) Round nose | 2,347 ft/s (715 m/s) | 1,835 ft·lbf (2,488 J) |
| Test barrel length: 24" Source(s): Cartridges of the World, 10th Ed., Barnes |
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The 7-30 Waters cartridge is a wildcat cartridge developed by author Ken Waters in 1976 to give better performance to lever action rifle shooters than the parent .30-30 Winchester cartridge, by providing a higher velocity and flatter trajectory with a smaller, lighter bullet. By 1984, Winchester introduced a Model 94 rifle chambered for the 7-30 Waters, establishing it as a commercial cartridge. In 1986, Thompson/Center began chambering 10", 14" and 20" Contender barrels for the cartridge. [1]
Contents |
Why neck down a .30 cal. cartridge to 7mm? This quote from a review of the 7-08 Rem. (a .308 Win. case necked down to 7mm), provides the answer.
| “ | Anything a 7mm can do, a .30 caliber of comparable sectional density and ballistic coefficient can also do. The catch is, in order to send a .30-caliber slug over a trajectory as flat as that 7mm bullet, about 20 percent more recoil is going to be generated. . . . [A bullet in] 7mm produces clearly superior downrange performance in terms of delivered energy and trajectory at any given recoil level [compared to a bullet in .30 caliber].[2] | ” |
There are two primary reasons a 7mm recoils less than an comparably effective .30 cal. cartridge: (1) to match the 7mm's ballistic coefficient requires a significantly heavier .30 cal bullet; and (2) to drive that heavier .30 cal bullet at similar velocities (for kinetic energy and wind resistance ("time-to-target")), requires more powder. This combination of heavier bullets with heavier powder charges significantly increases the recoil of the .30 caliber.
The .30-30 Winchester is typically limited to short ranges, primarily because of the relatively small case capacity and the 150 grain and 170 grain bullet weights. To compensate for this, Waters necked the cartridge down to use a 7mm bullet (.284 inches), rather than the original .308 caliber (7.62 mm) bullet. Because it was designed to function in lever action rifles, the 7-30 maintained the same low working pressure, but was able to fire bullets of lighter weight at higher velocity. A typical .30-30 factory load fires a 150 grain bullet at 2390 f/s, while the Federal Premium Vital-Shok 7-30 factory load fires a 120 grain Sierra GameKing bullet at 2700 f/s. Muzzle energy is just over 1900 ft-lbs for both loads, but the lighter weight bullet with higher velocity has a flatter trajectory.
As of November 2011, Hornady Manufacturing Company does not offer either 7-30 Waters LEVERevolution ammunition or 7mm/.284" FTX bullets. These would allow the safe use of pointed, ballistically efficient spitzer bullets in 7-30 lever action rifles' tubular magazines.
By 1982, Waters had perfected his new cartridge, firing a 139 grain flat point bullet at a muzzle velocity of 2600 f/s from a lever action rifle with a 24" barrel. By 1983, he had managed to attract the attention of Winchester, which led to the introduction of the Model 94XTR angle eject rifle and carbine in the new caliber the next year.[1] "[T]he 7-30 Waters cartridge, with its flatter trajectory and higher velocity, have made [the Model 94] what many consider to be an ideal mountain rifle: lightweight, but capable of reaching out for the longer shots."[3]
Thompson Center Arms began to chamber the 7-30 Waters in their Contender single shot pistol starting in 1986. Factory loads are capable of velocities of 2400 f/s from the 14" pistol barrel, making the 7-30 Waters one of the fastest commercial rounds available for the pistol. In addition, the single shot Contender can safely use pointed bullets, which allows the handloader to gain additional retained velocity at long ranges for uses such as metallic silhouette shooting.[4]
The 7-30 is suitable for hunting game up to and including deer sized animals, and with heavier bullets, black bear. Best performance is had with the rifle barrel; with the shorter carbine barrels the .30-30 is a better choice. With the long barrel, however, the 7-30 provides flatter trajectory, and a longer effective range, as well as reduced recoil from the lighter bullets. Despite the advantages, the 7-30 still lags far behind the venerable .30-30 in popularity, however.[1] Paco Kelly, of leverguns.com, wrote this about the 7-30: "I like the model 94 Winchesters....and the 7 Waters fits the standard 94 action very well. It is exactly what it was designed for...a light, handy, and fairly powerful round and rifle for deer and black bear."[5]
Where the 7-30 has gained a strong foothold is in handguns. In the field of handgun metallic silhouette shooting, a suitably loaded 7-30 Waters provides performance equal to other 7mm wildcats, such as the 7mm International Rimmed, but without the work of forming cases. It also adds the bonus of being able to shoot commercial ammunition, with some performance loss.[6][7]