6.5mm Creedmoor

6.5mm Creedmoor
Size comparison of some 6.5mm cartridges, left to right: .264 Winchester Magnum, 6.5×55mm Swedish, 6.5×52mm Carcano, .260 Remington, 6.5mm Creedmoor, 6.5mm Grendel
Type Centerfire rifle
Place of origin United States
Production history
Designed 2007
Manufacturer Hornady
Produced 2008
Specifications
Parent case .30 TC
Case type Rimless, bottleneck
Bullet diameter .2644 in (6.72 mm)
Neck diameter .2950 in (7.49 mm)
Shoulder diameter .4620 in (11.73 mm)
Base diameter .4703 in (11.95 mm)
Rim diameter .4730 in (12.01 mm)
Rim thickness .054 in (1.4 mm)
Case length 1.920 in (48.8 mm)
Overall length 2.825 in (71.8 mm)
Case capacity 52.5 gr H2O (3.40 cm3)
Rifling twist 1-8" (203 mm)
Primer type

Large rifle,

Small rifle (Lapua and Starline brass)
Maximum pressure (C.I.P.) 63,091 psi (435.00 MPa)
Maximum pressure (SAAMI) 62,000 psi (430 MPa)
Ballistic performance
Bullet mass/type Velocity Energy
120 gr (8 g) AMAX 3,020 ft/s (920 m/s) 2,430 ft⋅lbf (3,290 J)
143 gr (9 g) Hornady ELD-X 2,710 ft/s (830 m/s) 2,283 ft⋅lbf (3,095 J)

Test barrel length: 28 inch
Source(s): Hornady,[1] SAAMI,[2][3] C.I.P.

[4][5]

The 6.5mm Creedmoor, designated 6.5 Creedmoor by SAAMI, 6,5 Creedmoor by the C.I.P. or 6.5 CM or 6.5 CRDMR for short, is a centerfire rifle cartridge introduced by Hornady in 2007[6] as a modification of the .30 TC,[7] which was based on the .308 Winchester[8]. It was developed in partnership by Hornady Senior Ballistics Scientist, Dave Emary and Dennis DeMille, the VP of product development for Creedmoor Sports, hence the name. The cartridge was designed specifically for long-range target shooting,[6] although it is also achieving success in game hunting.[7] Bullet for bullet, the 6.5mm Creedmoor achieves a slower muzzle velocity than longer cartridges such as the 6.5-284 Norma or magnum cartridges such as the 6.5mm Remington Magnum. However, due to its overall length of 2.825 inches (71.8 mm), it is capable of being chambered in short-action bolt-action rifles and AR-10 semi-automatic rifles.

Design considerations

6.5 mm (.264") bullets, in general, are known for their relatively high sectional density[7] and ballistic coefficients, and have seen success in rifle competition. The 6.5mm Creedmoor was designed for target shooting at longer ranges and as such couples a sensible case volume (3.40 ml) to bore area (34.66 mm2/0.3466 cm2) ratio with ample space for loading relatively long slender projectiles that can provide good aerodynamic efficiency and external ballistic performance for the projectile diameter.[4] For some loads the 6.5mm Creedmoor is capable of duplicating the muzzle velocity[2] or trajectory[9] of the .300 Winchester Magnum while generating significantly lower recoil, based on lighter projectile weight. As this cartridge is designed for a bolt face diameter of .473 inches (roughly 12 mm), conversion of a short action rifle to another caliber (such as the .22-250 Remington, .243 Winchester or .300 Savage) with similar bolt face diameter generally requires little more than a simple barrel change.

Cartridge dimensions

The 6.5mm Creedmoor has 3.40 ml (52.5 grains H2O) cartridge case capacity.

6.5mm Creedmoor maximum C.I.P. cartridge dimensions. All sizes in millimeters (mm).[4]

Americans would define the shoulder angle at alpha/2 = 30 degrees. The common rifling twist rate for this cartridge is 203 mm (1 in 8 in), 6 grooves, Ø lands = 6.50 mm (0.256 in), Ø grooves = 6.71 mm (0.264 in), land width = 2.29 mm (0.090 in), and the primer type is large rifle or small rifle depending on the cartridge case manufacturer.[4]

According to the official C.I.P. (Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives) rulings the 6.5mm Creedmoor can handle up to 435.00 MPa (63,091 psi) Pmax piezo pressure. In C.I.P. regulated countries every rifle cartridge combo has to be proofed at 125% of this maximum C.I.P. pressure to certify for sale to consumers. This means that 6.5mm Creedmoor chambered arms in C.I.P. regulated countries are currently (2018) proof tested at 543.80 MPa (78,872 psi) PE piezo pressure.[4]

The SAAMI Maximum Average Pressure (MAP) for this cartridge is 62,000 psi (427.47 MPa) piezo pressure[10]

Performance

The 6.5mm Creedmoor is a medium power cartridge often compared to the .260 Remington and 6.5×47mm Lapua.[11] Three-hundred yard energy using 129 grain Hornady SST bullets is listed by an independent reviewer as 1,641 ft. lbs.[12] For the 140 grain bullet at 2,700 feet per second (823 m/s) initial velocity another reviewer reports an MPBR[13] for a six-inch-high target of 265 yards (242 m) and reports a manufacturer claim of "almost 1,600 ft⋅lbf (2,169 J)" of retained energy at 300 yards (274 m) using a 24-inch barrel.[14] SAAMI test data confirms 6.5 mm Creedmoor (15 feet from muzzle) velocity of 2,940 ft/s (896 m/s) for the 129 grain bullet and 2,690 ft/s (820 m/s) for the 140 grain bullet (which compares to .300 Winchester Magnum data of 2,930 ft/s (893 m/s) for a 200 grain bullet and 2,665 ft/s (812 m/s) for a 210 grain bullet).[2] Long-range shooter Ray "RayDog" Sanchez summarized the bolt-action Tubb 2000 rifle in 6.5mm Creedmoor as "boringly accurate" at 1,000 yards (914 m). He asserted the rifle and ammunition combination he used was able to maintain sub-MOA groups at 1,000 yards (914 m).[15]

Handloading

Only the very longest 140gr bullets will even reach the neck shoulder junction. Thanks to the relatively long neck it can be reloaded with long target bullets without placing the base of the bullet below the neck. This eliminates the "donut" problem seen by many cases that get reloaded over 20 times. Right to left: is a 123gr A-Max and Remington 140gr. Calipers are set to magazine length.

Handloading costs for the 6.5mm Creedmoor are roughly equivalent to other 6.5 mm cartridges, such as the 6.5×47mm Lapua, due to the availability of Lapua small primer brass for both cartridges.[16][17] Norma makes brass for the cartridge and Norma brass is available through several major retailers at approximately the same cost as Lapua brass. Lapua brass for 6.5×47 lasts for about 12 to 20 reloads.[18] Starline sells brass cases with either large or small primer pockets, with small pocket brass costing slightly more.[19] When the 6.5mm Creedmoor was first introduced it was advertised as a 60,000 psi capable case.[6] However, when it was placed into production Hornady listed it as 62,000 psi and had it SAAMI registered as such. For this reason many hand loaders have had poor experiences reloading for it. Blown primers on the first shot at 62,000 psi are not uncommon. Early shooting articles listed the ammo as loaded to 58,000 psi[20] but later ones list it as 57,000 psi.[21] This is because Hornady reduced the loads in its factory ammo because of complaints that it was often blowing primers.[22] Lapua delivered 6.5mm Creedmoor brass at Shot show 2017,[23] and production quantities became available via major retailers in second quarter 2017. The Lapua version has a small primer pocket.[16][24] Thus, loads from a Lapua Creedmoor are not safe in another manufacturer's Creedmoor brass that features a large primer pocket without applying proper hand loading test for pressure first. Also the use of a smaller diameter decapping rod is required to size and decap.

The 6.5mm Creedmoor as parent case

From left: 6mm Creedmoor, 6.5mm Creedmoor, .308 Winchester

The 6mm Creedmoor is a necked-down version of the 6.5mm Creedmoor using 6 mm (.243 inch) bullets, which are lighter than 6.5 mm bullets with similarly reduced recoil. John Snow at Outdoor Life designed it in 2009. As of May 2018, Savage Arms offers 3 bolt action rifles and 1 semiautomatic rifle chambered in 6mm Creedmoor.[25] As of May 2018, Hornady offers 87 gr Varmint Express, 103 gr Precision Hunter and 108 gr Match ammunition in 6mm Creedmoor.[26]

Military use

In October 2017, U.S. Special Operations Command tested the performance of 7.62×51mm NATO, .260 Remington, and 6.5mm Creedmoor cartridges out of SR-25, M110A1, and Mk 20 sniper rifles. SOCOM determined that 6.5 Creedmoor performed the best, doubling hit probability at 1,000 m (1,094 yd), increasing effective range by nearly half, reducing wind drift by a third and having less recoil than 7.62×51mm NATO rounds. Tests showed the .260 Remington and 6.5mm Creedmoor cartridges were similarly accurate and reliable and the external ballistic behavior was also very similar. The prevailing attitude is that there was more room with the 6.5mm Creedmoor to further develop projectiles and loads.[27] Because the two cartridges have similar dimensions, the same magazines can be used and a rifle can be converted with a barrel change. This led to its adoption and fielding by special operations snipers to replace the 7.62×51mm NATO cartridge in their semi-automatic sniper rifles, planned in early 2019. In response to SOCOM's adoption, the Department of Homeland Security also decided to adopt the round.[28][29]

See also

Notes

  1. ↑ UPDATED: 135gr to 145gr is no longer available with 2500 ft-lb Hornady's 6.5CM section Archived 2016-01-06 at the Wayback Machine. older: Hornady Manufacturing Company Archived 2011-07-12 at the Wayback Machine.
  2. 1 2 3 ANSI/SAAMI Velocity & Pressure Data: Centerfire Rifle Archived 2013-07-15 at WebCite
  3. ↑ "SAAMI CARTRIDGE AND CHAMBER DRAWING 6.5 CREEDMOOR" (PDF). Archived from the original (PDF) on 2018-03-28. Retrieved 2017-04-21.
  4. 1 2 3 4 5 C.I.P. TDCC datasheet 6,5 Creedmoor
  5. ↑ Shooting Times,
  6. 1 2 3 http://bulletin.accurateshooter.com/2007/11/hornady-introduces-new-65-creedmoor-cartridge/
  7. 1 2 3 Rupp, J. Scott (February 8, 2012). "The Versatile 6.5 Creedmoor". RifleShooter. Guns & Ammo Network. Retrieved August 13, 2014.
  8. ↑ Hornady Handbook 9, p296
  9. ↑ "Hornady ballistics charts" (PDF). Archived from the original (PDF) on 2015-08-24. Retrieved 2015-08-13.
  10. ↑ ANSI/SAAMI Velocity & Pressure Data: Centerfire Rifle
  11. ↑ Demigod short action 6.5mm comparison article
  12. ↑ D'Alessandro, Joe. "The Ruger M77 Hawkeye - 6.5 Creedmoor Part II Handloading the 6.5 Creedmoor for the M77". RealGuns.com. Retrieved August 22, 2015.
  13. ↑ http://www.chuckhawks.com/mpbr_hunting.htm maximum point blank range
  14. ↑ Wakeman, Randy (2012). "Savage Model 11 Lightweight Hunter 6.5mm Creedmoor Rifle". ChuckHawks.com. Retrieved August 22, 2015.
  15. ↑ 6.5mm Creedmoor - .260 Done Right? page 4
  16. 1 2 http://bulletin.accurateshooter.com/2016/11/lapua-now-offers-6-5-creedmoor-cartridge-brass/
  17. ↑ http://precisionrifleblog.com/2015/10/12/best-rifle-caliber/
  18. ↑ http://www.accurateshooter.com/featured/65x47/
  19. ↑ New rifle calibers from Starline
  20. ↑ http://www.shootingtimes.com/ammo/ammunition_st_creedmoor_201008/
  21. ↑ http://www.rifleshootermag.com/ammo/ammunition_rs_pedigreed_200811/
  22. ↑ http://bulletin.accurateshooter.com/2008/09/hornady-tempers-load-on-65-creedmoor-ammunition/
  23. ↑ http://forum.accurateshooter.com/threads/6-5-creedmoor-lapua-brass.3908200/page-3
  24. ↑ http://bulletin.accurateshooter.com/2017/02/lapua-6-5-creedmoor-brass-has-arrived-at-graf-sons/
  25. ↑ http://www.savagearms.com/firearms/?type_check%5B%5D=Centerfire&caliber_check%5B%5D=6MM%20CREEDMOOR
  26. ↑ https://www.hornady.com/ammunition/rifle/#!/
  27. ↑ USSOCOM Adopts 6.5 Creedmoor. soldiersystems.net, 23 March 2018
  28. ↑ SOCOM snipers will ditch their bullets for this new round next year. Military Times. 8 May 2018.
  29. ↑ Homeland Security shooters are dumping .308 for this long-range round. Military Times. 7 May 2018.
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