6.5mm Grendel

Rifle cartridge

6.5mm Grendel

6.5mm Grendel showing variety of bullets—144 gr (9.3 g) to 90 gr (5.8 g)

Type| Rifle
Place of origin| United States
Production history
Designer| Bill Alexander and Janne Pohjoispää
Designed| 2003[1]
Specifications
Parent case| .220 Russian (5.6×39mm)[2]
Case type| Rimless, bottleneck
Bullet diameter| 6.71 mm (0.264 in)
Land diameter| 6.50 mm (0.256 in)
Neck diameter| 7.44 mm (0.293 in)
Shoulder diameter| 10.87 mm (0.428 in)
Base diameter| 11.15 mm (0.439 in)
Rim diameter| 11.2 mm (0.44 in)
Rim thickness| 1.5 mm (0.059 in)
Case length| 38.7 mm (1.52 in)
Overall length| 57.5 mm (2.26 in)
Case capacity| 2.3 cm3 (35 gr H2O)
Rifling twist| 1 in 200 mm (8 in) or 1 in 230 mm (9 in)
Primer type| Small rifle
Maximum pressure| 360 MPa (52,000 psi)
Ballistic performance
| Bullet mass/type | Velocity | Energy

|
|

90 gr (6 g) Speer TNT | 2,880 ft/s (880 m/s) | 1,658 ft⋅lbf (2,248 J)
108 gr (7 g) Scenar (moly)[3] | 2,790 ft/s (850 m/s) | 1,866 ft⋅lbf (2,530 J)
120 gr (8 g) Norma FMJBT | 2,700 ft/s (820 m/s) | 1,942 ft⋅lbf (2,633 J)
123 gr (8 g) Sierra Matchking | 2,650 ft/s (810 m/s) | 1,917 ft⋅lbf (2,599 J)
130 gr (8 g) Norma | 2,510 ft/s (770 m/s) | 1,818 ft⋅lbf (2,465 J)
Test barrel length: 24 inches (610 mm)
Source(s): Alexander Arms Pressure-safe Load Data

The 6.5mm Grendel (6.5×38mm) is an intermediate cartridge jointly designed by British-American armorer Bill Alexander, competitive shooter Arne Brennan (of Houston, Texas) and Lapua ballistician Janne Pohjoispää, as a low-recoil, high-precision rifle cartridge specifically for the AR-15 platform at medium/long range (200–800 yard). It is an improved variation of the 6.5mm PPC.[4]

The 6.5mm Grendel cartridge was first unveiled in May 2003 at the Blackwater Training Facility in North Carolina, where it remained supersonic at 1,200 yd (1,100 m) range and out-shot the 7.62mm NATO with only half the recoil.[5] Since its introduction, it has proven to be a versatile cartridge and is now expanding into other firearm design platforms including bolt-action rifles and the Kalashnikov system.[6]

The name "Grendel" is inspired by the mythical monster antagonist from the Old English epic poem Beowulf.[7] It was a trademark owned by Alexander Arms (Bill Alexander's company in Radford, Virginia) and manufactured at Radford Arsenal,[8] until legally released in 2010 for SAAMI standardization with collaboration from Hornady.[7][9][10]

## Development and history

[edit]

The goal of the 6.5mm Grendel design was to create an effective STANAG magazine-length cartridge for the AR-15 platform that could reach 200–800 yd (180–730 m) and surpass the performance of the native 5.56mm NATO/.223 Remington cartridge. Constrained by the dimension of the STANAG magazines, the Grendel's designers decided to use a shorter, larger-diameter case for higher powder volume while allowing space for the long, streamlined, high ballistic coefficient 6.5mm (.264 cal.) bullets. Firing factory-loaded ammunition with bullets ranging from 90 to 129 grains (5.8 to 8.4 g), its muzzle velocity varies from 2,500 ft/s (760 m/s) with 129- and 130-grain (8.4 g) bullets to 2,900 ft/s (880 m/s) with 90 gr (5.8 g) bullets (similar in velocity to a 77-grain (5.0 g) 5.56 mm round). Depending on their case material and bullet weight, 6.5mm Grendel cartridges weigh 14.7 to 17.8 grams (227 to 275 gr).

The case head diameter of the Grendel is the same as that of the 5.6×39mm (.220 Russian), 7.62×39mm and 6.5mm PPC cases. This diameter is larger than the 5.56×45mm NATO, thereby necessitating the use of a non-standard AR-15 bolt. The increased case diameter results in a small reduction in the magazine ammo capacities. A 6.5mm Grendel magazine with the same dimensions as a 30-round STANAG magazine will hold 26 rounds of Grendel ammunition.

## Performance

[edit]

C-Products 26-round Grendel Magazine

Proponents assert that the Grendel is a good "middle ground" between the 5.56×45mm NATO and the 7.62×51mm NATO. It retains greater terminal energy at extended ranges than either of these cartridges due to its higher ballistic coefficient (BC).[2] For example, the 123 gr (8.0 g) 6.5 mm Grendel bullet has more kinetic energy and better body armor penetration at 1,000 m (1,100 yd) than the larger and heavier 147 gr (9.5 g) bullet of the M80 7.62mm NATO round.[11][12][13][14]

In order to obtain ballistics that are superior to the 7.62×51mm cartridge, a weapon with a longer barrel and firing a heavier bullet is necessary. To achieve the same results from shorter-length barrels, even heavier bullets are needed.[15]

### External ballistics

[edit]

Muzzle Velocity Change with Bullet Weight Bullet velocity: 24 inch (609.6 mm) barrel

| Bullet mass  | Muzzle velocity  | 1,000 meter velocity
gr  | g  | ft/s  | m/s  | ft/s  | m/s
Lapua Scenar  | 108  | 7.0  | 2,700  | 820  | 1,166  | 355
Lapua Scenar  | 123  | 8.0  | 2,620  | 800  | 1,222  | 372
Lapua FMJBT  | 144  | 9.3  | 2,450  | 750  | 1,213  | 370

As noted above, the Grendel case is very closely related to the .220 Russian case. In general, each additional grain of bullet weight will reduce muzzle velocity by 10.8 ft/s (50.8 m/s for each gram) and each additional inch of barrel length will increase muzzle velocity by 20 ft/s (2.4 m/s for each centimeter). Specific details are available as graphs derived from Alexander Arms' public domain load table linked below.

## LE and Military usage

[edit]

Serbia is in process of adopting a rifle made by Zastava Arms[16][better source needed] in 6.5 mm Grendel caliber as main armament for its armed forces. The rifle, designated Zastava M19, is a derivative of the previous-issue M70 rifle.[17] An American-manufactured rifle in 6.5mm Grendel caliber may also be adopted in armament for special forces units after it passes testing in Technical Testing Center.[citation needed] Three types of 6.5mm Grendel ammunition produced by Prvi Partizan of Užice, Serbia, will be tested for use with these rifles.[18][19][20][21] The French police tactical unit GIGN announced in 2025 that they are partnering with Swiss ammunition maker SwissP Defenc to produce 6.5 Grendel cartridges for the GIGN.[22] [23]

## See also

[edit]

* .220 Russian (5.6×39 mm)
* .224 Valkyrie (5.6×41 mm)
* 6mm PPC
* 6mm AR, a 6 mm wildcat version which shares 6.5 Grendel's casing, but sends a (usually) lighter projectile up to 1,000 yards (900 m).
* 6mm ARC, a factory cartridge with many similarities to the 6mm AR
* 6.5×55mm Swedish
* 6.5mm Creedmoor
* 6.5×42mm, also known as 6.5 MPC (Multi Purpose Cartridge), based on a necked up .223 Remington case.[24]
* 6.8mm Remington SPC
* 7.62×37mm Musang
* 7.62×39mm
* List of AR platform cartridges
* List of rifle cartridges
* Table of handgun and rifle cartridges

## References

[edit]

1. ^ "6.5mm Grendel (internet archive copy)". Alexander Arms. Archived from the original on January 9, 2012. Retrieved 2015-10-22.
2. ^ a b Guthrie, J (November 16, 2012). "6.5mm Grendel: The Round the Military Ought to Have". Shooting Times. Retrieved March 8, 2013.
3. ^ "Products - Lapua". Archived from the original on 2016-01-08. Retrieved 2016-01-04.
4. ^ Lewis, Jack (2007). The Gun Digest Book of Assault Weapons. Gun Digest Books. p. 77\. ISBN 978-0-89689-498-3.
5. ^ "6.5 Grendel". Alexander Arms. Retrieved 2021-06-04.
6. ^ Outdoor Hub, Prototype 6.5 Grendel AK Rifle from Definitive Arms, 13 October 2015
7. ^ a b Gash, Steve (2015-07-01). "Alexander Arms 6.5 Grendel Hunter Review". Gun Digest. Retrieved 2021-06-04.
8. ^ "Company History". Alexander Arms. Retrieved 2021-06-04.
9. ^ ""Alexander Arms Announces: The 6.5 Grendel Is An Official SAAMI Cartridge "". Archived from the original on 2019-08-13. Retrieved 2012-02-18.
10. ^ "6.5 Grendel is Approved as SAMMI Cartridge — Alexander Arms Gives up "6.5 Grendel" Trademark « Daily Bulletin".
11. ^ The Case for a General-Purpose Rifle and Machine Gun Cartridge (GPC) by Anthony G Williams Archived 2014-11-09 at the Wayback Machine
12. ^ Ehrhart, Thomas P. Increasing Small Arms Lethality in Afghanistan: Taking Back the Infantry Half Kilometer. pg 37-38
13. ^ Infantry Weapons Conference Report – SAdefensejournal.com, 9 January 2012
14. ^ Another 7.62mm Bullet For M-16s – Strategypage.com, 8 January 2012
15. ^ The Army’s Individual Carbine Competition: What’s Next? – SAdefensejournal.com, 24 October 2013
16. ^ "Untitled photograph of multiple guns". Archived from the original on 2016-08-27. Retrieved 2016-07-26.
17. ^ "FIRST Military 6.5 Grendel Rifle? – 6.5mm Zastava M17 AK DMR in Testing by Serbian Army -". 22 November 2017.
18. ^ "Prvi Partizan Ammunition".
19. ^ "Prvi Partizan Ammunition".
20. ^ "Prvi Partizan Ammunition".
21. ^ "Војска Србије". Archived from the original on 2016-07-24. Retrieved 2016-07-26.
22. ^ "SwissP Defence and GIGN present the 6.5 Grendel at SOFINS 2025".
23. ^ "SwissP Defence and GIGN present the 6.5 Grendel at SOFINS 2025".
24. ^ The 6.5 MPC cartridge by SSK developed by J.D. Jones at SSK Industries | Article on DefenseReview.com

## Bibliography

[edit]

* Guns 'n' Ammo: Book of the AR-15, 2004, "The 6.5mm Grendel", David Fortier, p. 66.
* Special Weapons for Military & Police, Annual #27 2004, "Beyond the 5.56mm NATO", Stan Crist, pp. 62–67.
* Guns 'n' Ammo: Book of the AR-15, 2005, "6.5mm Grendel and 6.8 SPC", David Fortier, pp. 32–44.
* Shooting Times, February 2005, "Cooking up Loads for the 6.5mm Grendel", David Fortier, pp. 52–56.
* Shooting Illustrated, September 2005, "6.5mm Grendel and Alexander Arms", J. Guthrie, pp. 34–37, 67–69.
* Petersen's: Rifle Shooter, March/April 2006, "Cartridge Efficiency—Why case shape matters", M. L. McPherson, pp. 22–24.
* Shooting Times, January 2007, "Other AR Chamberings", Sidebar Article, David Fortier, p. 56.
* Special Weapons, Semi-Annual #50 2007, "The Super Versatile AR", Charlie Cutshaw, pp. 44–45, 80–83.
* Special Weapons, Semi-Annual #50 2007, "5.56mm NATO Alternatives", Stan Crist, pp. 52–59.
* Shooting Times, March 2007, "Les Baer's 6.5mm Grendel AR Sets a New Standard", David Fortier, pp. 26–32.
* Special Weapons for Military & Police #52, Spring 2007, "BETTER-IDEA 6.5mm GRENDEL", Stan Crist
* Special Weapons for Military & Police #52, Spring 2007, "New Battlefield Requirements—New Rifles and Ammo Needed", Charlie Cutshaw

## External links

[edit]

Wikimedia Commons has media related to 6.5 mm Grendel.

* http://www.alexanderarms.com/

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Intermediate cartridges

LE & Paramilitary|

* .22 Spitfire
* .221 Remington Fireball
* .300 AAC Blackout
* .375 SOCOM
* .450 Bushmaster
* .45 Raptor
* .458 HAM'R
* .458 SOCOM
* .50 Beowulf
* .500 Auto Max
* 6.5mm Grendel
* 7.62×37mm Musang
* 7.62×45mm Pindad
* 8.6 mm Blackout
* 9×39mm
* .510 Whisper

Service issue|

* 5.45×39mm
* 5.56×45mm NATO
* 5.8×42mm
* .30 Carbine
* 6.8×51mm
* 7.62×39mm
* 7.62×45mm
* 7.92×33mm Kurz

Premodern|

* 10.4x38mmR
* 10.4×47mmR
* 11x42mmR Albini-Comblain
* 11×50mmR Comblain
* 11mm Beaumont
* 12.17×42mm RF
* 12x46mmR Musket Spain XPL
* .22 Winchester Centerfire
* .25-20 Winchester
* .32-20 Winchester
* .43 Spanish Carbine
* .45-60 Winchester
* .45-75 WCF
* .433 Egyptian
* .50-70 Government
* 14×33mmR Wänzl
* 15.24х40R Krnka

Commercial|

* Calhoon cartridges
* .20 VarTarg
* 5 mm/35 SMc
* .20 Tactical
* .204 Ruger
* 5.6×39mm
* .22-250 Remington
* .22 PPC
* .219 Zipper
* .224 Valkyrie
* .222 Remington
* .225 Winchester
* 6mm BR
* 6mm PPC
* 6 mm XC
* 6mm ARC
* 6.5mm Creedmoor
* 6mm AR
* 6×45mm
* .25-45 Sharps
* .250-3000 Savage
* 6.5×47mm Lapua
* 6.8 Western
* .270 Winchester
* .277 Wolverine
* 7mm Backcountry
* 7mm BR Remington
* 7×33mm Sako
* 7.62×40mm Wilson Tactical
* .30 Remington AR
* .350 Legend
* .35 Remington
* .360 Buckhammer
* .400 Legend
* .401 Winchester Self-Loading

Prototype|

* .351 Winchester Self-Loading
* .345 Winchester Self-Loading
* 4.85×49mm
* 5.6x48mm Eiger
* 6×45mm SAW
* 6.45×48mm XPL Swiss
* 6.5×39mm
* 6.8mm Remington SPC
* .280 British
* 7.5×38mm
* 7.5×38mm
* 7.65×33mm
* 7.65×35mm
* 7.75×39mm GeCo
* 7.92×41mm
* 12.7×55mm STs-130

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Cartridges derived from the 7.62×39mm or its derivatives

First generation derivatives|

* 5.45×39mm
* 5.6×39mm/.220 Russian
* 9×39mm
* .366 TKM

Second generation derivatives|

| based on 5.6×39mm/.220 Russian|

* .22 PPC
* 6 mm PPC
* 6.5mm Grendel
* .30 Walker

|

Based on 5.45×39mm|

* 5.45×39mm PSP

Third generation derivatives|

| based on 6.5mm Grendel|

* 6mm AR
* 6mm ARC

|

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