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6.5 Grendel FAQ (264 LBC-AR, 6.5 CSS, 6.5 Sporter)


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  • 6.5 Grendel FAQ (264 LBC-AR, 6.5 CSS, 6.5 Sporter)

    The 6.5 Grendel was created by Alexander Arms, LLC and Arne Brennan, former head of Competition Shooting Sports, Inc.

    Development begain in 1998 with the goal to offer the range performance of the 7.62 NATO (.308 Winchester), but do so in the AR15 / M16 platform. As part of this development, flexibility in projectile weight and design was a major criteria as every caliber from .224 to .308 was evaluated. Selection of the 6.5mm caliber combined with our case design allows use of bullets from 85 grains to 144 grain in magazine length loadings. 6.5mm bullets provide high ballistic coefficients particularly in the 100-144 weight range with OTM bullets ranging in BC from .444 to .615. In comparison, the 77 grain Sierra in .224 has a .362 BC. In addition to OTM projectiles, there is an abudance of hunting projectiles from Nosler, Swift, Speer and Remington available that will operate magaizne length at respectable velocities that allow the cartridge to be used for a variety of game animals including deer, hogs and sheep. There are also FMJ projectiles in 100, 120 and 144 grain weights available in 6.5mm.

    The case design of the 6.5 Grendel was born from the world record holding PPC family (22 and 6mm) of cartridges. Dr Lou Palmisano (Doc PPC), who became a friend of Arne Brennan, watched Arne's development work with great interest as a new variant of his cartridge designs showed its capabilities with higher projectle weights in a platform such as the AR15 / M16. The case for this family of cartridges were designed to be highly efficient combustion chambers that deliver incredible consistancy, often with velocity variations between shots in the single digits ( Consitent Velocity between shots is a major contributor to accuracy) The initial result of Arne's work became a 6.5 PPC optimized to work within the AR15 platform.

    In 2002, Bill Alexander was introduced to Arne Brennan by Lothar Walther and Arne shared with Bill Alexander his work and performance obtained over many thousands of rounds of shooting. While the "Grendel" was unveiled in 2003 at Blackwater, the Grendel case was modified by Brennan, Alexander and Lapua into a production version best described a 6.5 PPC with a blown forward shoulder and shorter neck.

    Case capacity of the Grendel is just over 35 grains of H20 with powder capacity within 5% of the 6 BR case. During development, a 6.5 BR AR15 was built and tested for many thousands of rounds. While the BR offered a slight increase in case capacity, the gain in velocity was insignificant. This insignificant gain in velocity, combined with the reduced magazine capacity (only 8 rounds in the space of a 20 round .223 Rem magazines), along with the extensive modifications required in the magazines made the BR case impracticle for the commercial market or any other volume user.

    Testing and proof work have been underway to test the 6.5 Grendel in benchrest competition (the land of the 22 PPC and 6 PPC) and initial results are showing great promise of being competitive with the smaller caliber PPC family members. On March 6, 2006, Arne Brennan achieved a witnessed 1.198 inch 5 shot group at 660 yards using the Lapua 108 Scenar Projectile with N133 powder... no voodoo or black magic powder / bullets there. In addition, the 6.5 Grendel is being used or being developed in F-Class, Rifle and Handgun Silhouette and of course, High Power Rifle Competition. Further, the 6.5 Grendel is capable of making the 320 power factor (major) in 16-20 inch barrel AR's. With permission from the Commanding Officers, we are allowed to state that both the US Army Marksmanship Unit and US Air Force Shooting Team have match Grendel's which are in testing.

    In January 2010, Les Baer discontinued offering "6.5 Grendel" branded products and launched the "264 LBC-AR" having worked with Hornady and Black Hills Ammunition to supply a complete product offering of Rifles, Uppers, Dies, Brass and Loaded Ammo. While Alexander Arms allows other manufacturers to use the "6.5 Grendel" brand under a licensing program, Les Baer has chosen to make it's cartridge "open source". As such, any manufacturer is permitted to use the "264 LBC-AR" chambering and branding without licensing or royalties. Competition Shooting Sports, who always offered a specialized chambering in its specific products, changed the branding of its products to "6.5 CSS" in 2006 so not to conflict with Alexander Arms products. As follow-up to Les Baer's release, Competition Shooting Sports has also released the availability of "264 LBC-AR" products.

    Hunting with the 6.5 Grendel is not much of a challenge given the wide availability of premium hunting 6.5mm bullets available including Nosler Ballistic Tips, Nosler Partitions, Swift A-Frame and Swift Scirrocco to name but a few - all work from the magazine. End users have already been using the Grendel to great success on Deer, Hogs, Antelope, and Coyotes.

    The Grendel has been fully tested in both semi-auto and full auto operation with no issues. Key to the operational success of the 6.5 Grendel has been the engineering of proper barrel extensions and magazines.

    Cartridge Data
    Case length: 38.7mm or 1.524"
    Case rim: .441"
    Case rim thickness: 0.059"
    Case base: .439"
    Case shoulder diameter: .428"
    Case taper: 0.65° each side
    Case shoulder angle: 30°
    Case maximum loaded neck diameter: .293"
    Maximum loaded overall length (OAL) in 6.5 Grendel-specific AR15 magazines: 2.265"
    Maximum peak operating pressure: 50,000 psi. Note: The peak pressure of factory ammunition is restricted by the safe, long-term operating limits of the AR15 platform.
    Usable case capacity with a 123gr Lapua Scenar bullet seated magazine length is 30.0 grains of BLC2 powder.

    Rifling is of the "Boots" Obermeyer 5R type
    Rifling is 6-groove, righthand twist
    Rifling twist rate varies by model, but ranges from 1:7.5 to 1:9
    Bore diameter is .2638"
    Lands diameter is .256"

    Sample Performance Data by Barrel Length
    Barrel 16.1"
    144 Lapua FMJBT (.636 BC), AA2520, CCI 450 = 2275 fps
    139 Lapua Scenar (.615 BC), AA2520, CCI 450 = 2305 fps
    130 Norma (.590 BC), AA2520, CCI 450 = 2425 fps
    130 Swift (.571 BC), AA2520, CCI 450 = 2425 fps
    Note: OAL = 2.255"

    • AA Tactical 14.5" complete rifle, plastic furniture and M4 buttstock, weighs 6.25 lbs.

    Alexander Arms can be found at phone#: (540) 639 8356

    Competition Shooting Sports, Inc can be found at : 770-889-9998

    Uppers and Barrel Kits are currently manufactured by both companies.

    Competition Shooting Sports, CSS offers its own complete uppers and barrel, bolt & gas block packages in 6.5 CSS and 264 LBC-AR.

    Midway USA offers standard Alexander Arms uppers and supplies.

    Available Configurations: complete rifles or just uppers with barrel lengths of 14.5" 16.1", 19.5", 20", 24" and 28 inches ranging from mild to wild.

    Flash suppressors/muzzle brakes - The Tactical and GDMR series currently have flash hiders available. The GCS series by CSS has flash hiders on 16.1 and 20 inch models with compatibility for supressors.

    Magazines - Creative Products is currently selling 26 round stainless steel teflon coated magazines equipped with anti-tilt followers. A 17 round magazine of the same materials, albeit shorter, has also been released. 10 round magazines are made by Alexander Arms.

    Forends: Depending on configuration, the Grendel makes use of carbine, mid-length and rifle length gas systems with gas ports tuned to individual barrel lengths.

    Lower Receiver Compatibility: 6.5 Grendel uppers can be installed on any AR15 lower. No change is required to the lower receiver group.

    Buffers: The Grendel requires no change to the buffer system.

    Butt stocks, pads: Can use any buttstock offered for the AR15.

    Ammunition: Since 2004, Ammo and Brass have been available from Alexander Arms.

    At SHOT 2006, Wolf published their availability of 6.5 Grendel ammo offerings beginning with a 120 MPT and 123 SP loading. Ammo is scheduled to arrive in the USA in early Summer 2006. Wolf Ammo is brass cased, boxer primed and is reloadable with no modificaiton. Estimated price point per box is $5-$6 (20 rounds).

    Lapua has also entered agreement to sell and distribute Lapua headstamped brass and loaded ammo worldwide. While exact specs are unknown, my suggestion has been for Lapua to offer their 108 grain Scenar with a .478 BC. This loading can achieve 2600+ fps in a 16 inch barrel while operating at safe pressures. Also this would replicate trajectory performance of the 7.62 NATO with 168 grian bullets (24 inch barrel loadings)

    Les Baer contracted with Black Hills ammunition to produce ammo under the "6.5 Grendel" brand. In January 2010, Les Baer discontinued the "6.5 Grendel" brand and released 264 LBC-AR ammo produced by Black Hills Ammunition.

    SSK Industries is offering Contender, Encore and AR15 barrels as well as some AR15 uppers

    Competition Shooting Sports offers AR15 barrel, bolt and gas block packages as well as complete rifles and uppers.

    Why the strange name for this cartridge?
    Grendel is the name of a mythical beast, a vicious monster, from the epic poem Beowulf, written many centuries ago. In one scene, Grendel smashes through the iron fittings of a heavy oak door and bursts into a dining hall where many Vikings are sleeping and attacks them: “Straightway he seized a sleeping warrior for the first, and tore him fiercely asunder, the bone-frame bit, drank blood in streams, swallowed him piecemeal; swiftly thus the lifeless corse was clear devoured, e’en feet and hands.” Bill Alexander chose the name Grendel to compliment the 50 Beowulf his company also produces. Another offering Alexander Arms is known as the 21 Genghis which is the 5.45x39 Russian cartridge and the Genghis is an AR15 type rifle built to consume the steel case ammunition available in this chambering.

    Top Question Asked About The Grendel

    1. What will the 6.5 Grendel do that I cant do with a .223 Remington?

    Answer - The 6.5 Grendel extends the range capability of the AR15 platform and allows the AR15 to be used for ethical hunting of medium game such as Deer, Hogs and Sheep.

    2. Is the military doing anything with the 6.5 Grendel?
    Answer - Other then the items mentioned above regarding the USAMU and USAF Shooting Team with permission, Alexander Arms and Competition Shooting Sports never discuss military orders or discussions. If something is happening, it is up to the military parties involved to release that information.

    3. What is Grendel recoil like?
    Answer - The 6.5 Grendel recoils slightly more then the .223 Remington (Heavier Bullets = Increased Recoil).. However, calculations show the recoil to be 40-60% less then the .308 Winchester.

    4. The Grendel case is very straight, how does that impact feeding?
    Answer - Actually, the Grendel has more taper then a 7.62 NATO and the 5.56 NATO..

    5. Isnt a large rifle primer better then a small rifle primer for military purposes?
    Answer - The 5.56 NATO has a small primer and has survived for over 40 years. While it lacks terminal energy, the primer has nothing to do with this factor.

    6. The 7.62x39 has never worked well in the AR, why does the Grendel.
    Answer - First, the Grendel does not have as much case taper as the 7.62x39. The 7.62x39 due to its case taper requires a magazine with a pronounced curve (like the AK47) to work well. The AR15 with its mag well require a straight magazine section. The Grendel with its less pronounced taper then the 7.62x39 works. Second, Alx Arms designed new barrel extensions and magazines specifically for the Grendel.

    7. How does it perform in shorter barrels?
    Answer - The Grendel is a high efficiency cartridge and therefore burns its powder very well in short barrels. Barrels have been made as short as 12 inches with no problem. In fact, the 6.5 Grendel has already been used in handgun silhouette competition and won.

    8. How does the 6.5 Grendel perform less then 300 meters since it seems to be designed for beyond 300 meters?
    Answer - Yes, the 6.5 Grendel was designed for long distance shooting. However, the Grendel's projectiles dont magically appear at 300 meters and go the distance. Many people have had great success hunting deer and wild boar at close range. History is the ultimate judge and 6.5mm has been a proven hunting caliber for well over a hundred years even at moderate velocities.

    9. How do the bolts hold up?
    Answer - the only bolt that I have seen broken was one after 3000 rounds of excessive abuse running very high pressure loads (65,000 PSI). Even then, only one lug broke and the gun was back in working order with a quick 2 minute bolt swap. In 9 years of work on this, that is the only bolt I have ever seen fail.

    10. What if I need a replacement bolt?
    Answer - no problem, contact the manufacturer of your barrel for a replacement.

    11. I want to shoot 1000 yards with this cartridge, what should I do to set it up properly?
    Answer - When shooting at 1000 yards, you need to be sure your scope has sufficient elevation adjustment to correct for bullet drop. If you do not have a base with elevation built in, you need a scope with a minimum of 90 minutes of elevation (+/- 45 minutes). If you incorporate a 20 moa base, you can use a scope with a minimum of 50 minutes of elevation (+/- 25 minutes) although a scope with 75 minutes of elevation (+/- 37.5 minutes) will keep you out of the edges of the elevation adjustment range.

    12. What is practical range limit for different barrel lengths?
    Answer - While the cartridge will perform with 14.5 and 16 inch barrels, most people find that 18, 20 and 22 inches are the ideal barrel lengths for target shooting and hunting. Either of these 3 barrel lengths will allow medium game hunting out to 300 yards and allow accurate shooting to 600 yards. If you are going to be doing a lot of long range shooting beyond 600 yards, you should use a 28 inch barrel to extract as much velocity as possible.

    13. I will be hand loading my own ammo, what are the best bullets to consider?
    Answer - While many people are focused with 120+ grain bullets because of their ballistic coefficient, the best bullets to consider in cartridge of this size range from 81.5 to 108 grains. This lighter bullet weights will let you use a wide assortment of both ball and extruded powders and obtain respectable velocities at safe pressures. Bullets 120 grains or greater in weight are very powder choice limited compared to the lighter bullets.
    The 108 Grain Lapua can be safely loaded to achieve a trajectory match with the 7.62 NATO M118 LR round. For hunting, the Nosler 100-grain Ballistic Tip and Partition bullets are outstanding as is the Hornady 95 VMAX and Speer 90 grain TNT. Other bullets to consider include the Berger 85 grain flat base and Berger 100 grain HPBT.

    14. Why is the cartridge rated at 49,000 to 51,000 PSI in published load data? Cant the brass handle more?
    Answer - Because the AR-15 rifle is the main platform this cartridge was developed for, the rifle platform became the pressure-limiting factor due to its bolt/ locking lug design and bolt thrust limitations.

    15. What are the details of the all chambering options and names?
    Answer -
    “6.5 Grendel” .300 neck diameter with compound angle throat - Alexander Arms Chamber
    “6.5 CSS” .295 neck diameter with compound angle throat for AR-15 rifles - Competition Shooting Sports / Lothar Walther Chamber in use since 2004.
    “.264 LBC-AR” .295 neck diameter with 1.5 degree throat for AR-15 rifles - Les Baer Custom Chamber - - Open Source Chamber - Contact Dave Kiff at Pacific Tool to obtain reamer
    “6.5 PPCX” .292 neck diameter with 1.5 degree throat for bolt action rifles only - Open Source Chamber - Contact Dave Kiff at Pacific Tool to obtain reamer - Chamber used to fire witnessed 1.18" five shot group at 660 yards using Lapua 108.
    "6.5 BPC" Special Purpose Bench Rest Bolt Action Chamber - Open Source Chamber - Contact Dave Kiff at Pacific Tool to obtain reamer
    Last edited by tx65; 02-08-2011, 17:32.