7mm-30RG

The 7mm-30 RG, or 7mm-30 RealGuns, is a .284" caliber, moderate capacity, high intensity wildcat cartridge. Based on the 30 Remington AR commercial cartridge, the 7mm-30 RG was developed as a moderate velocity, low report, medium size game or special applications cartridge. The cartridge's relatively short length and moderate powder capacity make it ideally suited for compact and light bolt action repeaters based on the mini-Mauser design.

The cartridge was designed by Joseph D'Alessandro, Editor of RealGuns.Com. Drawings and prototype cases were completed on 4/24/2010. The design was frozen and committed to tooling on 6/22/2010. The cartridge design was first documented in an article that appears on the realguns[1] website. The first article was posted in July 30, 2010 with additional project installments ongoing as a published series.

Development
The original drawings and dimensional specifications were produced with RCBSLoad, the initial internal and external ballistic performance projections were made with QuickLOAD. Subsequently, internal ballistics were assessed with an Oehler Model 43 utilizing strain gauge technology and external and terminal ballistics data were collected during live fire tests. The prototype firearm was a 21" barrel Remington 799 mini-Mauser bolt action rifle, modified to specifications by gunsmith Dennis Olson of Plains, Montana. The original chamber reamers, sizer die and headspace gauges were produced by Pacific Tool & Gauge of White City, Oregon, the original handloading dies were produced inhouse by RealGuns.Com personnel. All tooling was produced and marked to the cartridge designer's specifications.

Preliminary velocity recorded was: 2900 fps - 120 grain bullets, 2700 fps - 140 grain bullets, 2600 fps - 150 grain bullets from the 21" barrel prototype firearm. The cartridge is in active final development at this time so, for safety sake, specific component and exterior ballistic data is being withheld until testing is completed and verified within the next 60 days.

The operating pressure goal is 65,000 PSI, or 10,000 PSI greater than the parent cartridge. While not exceptional as a modern cartridge intended for use in strong bolt and falling block type firearms, the pressure is excessive for AR-15 applications. Cases are formed in two steps; mechanically by running 30 Remington AR cases through a 7mm-30 RG sizer die to reduce neck diameter from the 30 caliber 0.3420" neck diameter to 0.3200" to accommodate the .284" bullet, then fireforming to fully position and shape the case shoulders and body. Reloading fired cases requires only mechanical sizing n this regard. Because case forming is modest, case life is long and no annealing steps are required specifically as a result of case forming.

Dimensions
The parent 30 Remington AR was itself a derivative of the .284 Winchester. In comparison to the parent 30 Remington AR case, the 7mm-30 RG retains the same cartridge overall length and the same case length. The neck length has been shortened proportionally to the 0.284" diameter bullet and the shoulders have been located farther forward and formed in a more acute angle to increase case capacity and to optimize shoulder angle for case life and ballistic performance. Case capacity to spill over full is forty-five grains of water, one grain more than the parent case. In further context the 7mm-30 RG has one and one half grains greater capacity than the 22-250 Remington and one grain more than the .30-30 WCF.

Because of the cases large diameter body, only some mini-Mauser actions are suitable as repeaters. The prototype began life as a Remington Model 799, chambered for the .22-250 Remington. This particular mini-Mauser configuration has a wide 0.630" magazine feed port, which is substantially larger than other mini-Mauser configurations.

Usefulness
The cartridge is easy to form, parent brass is inexpensive, as are the rest of the components needed to assemble ammunition. With more than acceptable ballistics with bullet weights up through 160 grains and kenetic energy at the muzzle in the 2,200 - 2,300 ft/lbs range, it is a natural for deer, black bear and hog hunting. With lighter bullet weights it is a natural for coyote hunting. 7mm bullets are available in a wide selection of construction types making them suitable for many applications. The very short cartridge length makes it suitable for very compact and light weight firearms and the cartridge's modest powder capacity permits barrel lengths of 20"-21" to deliver near full performance.

The drawback for this cartridge is common to all wildcat cartridges. Machine tools and dies must be made, ammunition must be hand assembled and a firearm must be modified to the application. The cost of this project was approximately $2,500 for materials, labor and outside services.