For the 1906 vintage rimless cartridge, see .30 Remington.

The .30 Remington AR / 7x39mm Remington AR is an intermediate cartridge created in 2008 by Remington Arms to fill a perceived gap in performance on large game between the .223 Remington and larger cartridges such as the .308 Winchester.[1] The design of the cartridge is considered a joint effort between companies under the "Freedom Group" name through a private equity firm[1] and included such companies as Bushmaster, DPMS and Remington itself. It is a rebated rim cartridge designed to fit Remington's R-15 semiautomatic hunting rifle. It was made to fit the dimensional constraints of the AR-15 magazine and is based on a modification of the .450 Bushmaster, which in turn is based on the .284 Winchester.[2]

Remington was the only company that manufactured this ammunition and its components.[3] The cartridge was a commercial failure and has been discontinued by Remington.

The .30 Remington AR cartridge has a significantly wider diameter than the .223 Remington

Design

Starting with a .450 Bushmaster case, Remington trimmed the length to 1.525 in from the original 1.7 and necked it down to accept a conical .308 in diameter bullet with a 25-degree shoulder.[4]

The rim size is .492 in and because the round generates 55,000 psi, Remington opted to use a .308 rifle bolt in a 5.56-sized rifle for increased case support.[4] The rim was widened from the .473 in of the parent case to prevent the use of a weaker .450 Bushmaster bolt with this cartridge. With a 150 grain bullet, the round travels at 2,575 feet per second (fps).[5]

Performance

Performance tests between the .30 RAR and the .308 Winchester show that while the .30 RAR does have a good muzzle velocity, the energy it is capable of delivering on target at around 400 yards decreases significantly.[6] Combined with the poorer ballistic coefficients of the lighter projectiles (.267 for the 125-grain Core-Lokt), this makes the .30 RAR a cartridge suited to ranges around 300 to 400 yards, although this can be extended with projectiles of higher ballistic coefficient (.341 for the Speer TNT 125 grain).[citation needed]

A side effect of the short, wide case is that the Remington R-15 rifle, which was designed alongside the cartridge, uses a four-round, single-stack magazine.[1]

See also

References

  1. ^ a b c Nischalke, Mike "The R-15 And The .30 RAR", Shooting Times, Online Article, accessed 13 January 2010
  2. ^ Sweeney, Patrick (2010). The Gun Digest Book of The AR-15. Iola, Wisconsin: Gun Digest Books. pp. 174–175. ISBN 978-1-4402-1622-0.
  3. ^ Mann, Richard A. (2014). GunDigest Shooter's Guide to the AR-15. Iola, Wisconsin: Krause Publications. pp. 66–67. ISBN 978-1-4402-3847-5.
  4. ^ a b Woodard, W. Todd (2016). Cartridges of the World: A Complete and Illustrated Reference for Over 1500 Cartridges. Iola, wisconsin: F+W Media, Inc. p. 118. ISBN 978-1-4402-4642-5.
  5. ^ Zwoll, Wayne van (29 November 2012). Gun Digest Shooter's Guide to Rifles. Iola, Wisconsin: Gun Digest Books. p. 124. ISBN 978-1-4402-3076-9.
  6. ^ "Remington Introduces new Remington 30 AR Cartridge". Accurate Shooter Bulletin. 2008. Retrieved 13 January 2010.
Allikas: http://en.wikipedia.org/wiki/.30_RAR
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