GUN 6.5 Grendel and the AR15 Platform

Discussion in 'On Topic' started by TwistedMind, Dec 14, 2007.

  1. TwistedMind

    TwistedMind New Member

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    So I was going to post this in the other thread but it is way to much info to be a random post in a obscure thread.

    Please note I am not the original author, I am mearly moving it from one forum to our forum.

    6.5 Grendel and you

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    The 6.5 Grendel was created by Alexander Arms, LLC and 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), a friend of Arne Brennan, watched the 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 Grendel case was born from the PPC, but was modified by Brennan and Alexander to refine performance and maintain the record setting performance dynamics, but in 6.5mm, not 6mm.

    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 or will be used for competition in 2006.

    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, Coyotes and prarie dogs.

    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.

    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"

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


    Alexander Arms can be found at www.alexanderarms.com phone#: (540) 639 8356

    Competition Shooting Sports, Inc can be found at www.competitionshooting.com : 281-330-0352

    Uppers in 6.5 Grendel are currently manufactured by both companies.

    Dealers:

    Competition Shooting Sports ,Arne Brennan of CSS, aka "TX65" , is an Industry Partner on AR15.com. In addition to Alexander Arms uppers, CSS offers its own complete rifles, complete uppers and barrel, bolt & gas block packages.

    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 www.cproductsllc.com is currently selling 26 round stainless steel teflon coated magazines equipped with anti-tilt followers. A 20 round magazine of the same materials, albeit shorter, will be available very soon. 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: The Grendel can use any buttstock offered for the AR15.

    Ammunition: Ammo and Brass have been available since 2004 from Alexander Arms. Alexander Arms brass is manufactured under agreement with NAMMO. There have been 4 factory loaded ammunition offerings in 90, 120, 123 and 129 grain bullets.

    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)

    Agreements have been reached for a number of other known AR15 manufacturers to produce 6.5 Grendel AR15 uppers / rifles. In addition,

    SG&Y Rifles (Speedy Gonzalez) is building custom bolt actions www.sgyrifles.com

    Brockman Rifles is doing CZ527 barrel changes www.brockmanrifles.com

    SSK Industries is offering Contender, Encore and AR15 barrels as well as some AR15 uppers www.sskindustries.com

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


    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, call Alexander Arms and they will replace it for less then $70.00
     
  2. TwistedMind

    TwistedMind New Member

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    6.5 GRENDEL BALLISTICS GRAPHS

    If you're planning on using factory match ammunition in a 6.5 Grendel, here are some simple graphics generated from Excel that compare three AR15 factory loads (and one for the AR10) out to 1000 yards. The first three graphs are all for 24" barrels; the following three are for 16" barrels.

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    The figures I used are included on the charts, if someone wants to cross-check my results, and I used the online JBM Small Arms Ballistics calculator.

    These charts are an attempt at as close an apples-to-apples comparison as is possible, using only factory ammo and Sierra MatchKing bullets.

    I've now created some charts for 16" barrels comparing the 6.5 Grendel to other combat cartridges.

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    Previously, I posted some charts comparing Black Hills 6.5 Grendel 123 SMK to Black Hills match loads in 5.56 and 7.62. Both those loads have military counterparts, Mk262 and M118LR, which are loaded hotter. This new set of charts makes that comparison, and also throws in Alexander Arms' new 130 Swift Scirocco load, which could be a useful penetration load for LE, in addition to the obvious hunting use.

    I'm struck how similar all three MatchKing trajectories are, that should simplify the training for those adding 6.5 Grendel capability to their toolbox.

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    WOLF 6.5 GRENDEL PRODUCTION AMMO

    Last week (February 2007), I got most of a case of the new Wolf 6.5 Grendel ammo from Alexander Arms to review.

    This first loading has a 123-grain hunting soft-point. It's not going to outshoot 7.62 NATO M118LR like a 6.5 Grendel 123gr Lapua Scenar can, but my wallet likes it (Cabela's $10.99/20)!

    The velocity is still below specification, being 2370 fps from a chrome-lined 16" bbl, but that will have to be incrementally improved in future lots. Bill Alexander posted, "At present, this is running about 50 to 80 fps slower than I would ideally like for the round, but the bullet bearing length will always preclude the velocities matching those of the 123-grain Lapua Scenar and Sierra MatchKing loads."

    Some states, like Minnesota, don't allow any .223 round for deer hunting, so this is just what the doctor ordered! What's not to like about big-game hunting with your favorite black rifle in a traditional deer caliber like 6.5mm (with affordable ammo)? Does it get any better than that
     
    Last edited: Dec 14, 2007
  3. TwistedMind

    TwistedMind New Member

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    INDEPENDENTLY VERIFIED 6.5 GRENDEL VELOCITIES

    The following data is from David Fortier's 6.5 Grendel article on page 55 of Guns & Ammo's Book of the AR15 2006.

    90 Speer TNT

    14.5 bbl = 2686 fps
    16 bbl = 2760 fps
    24 bbl = 2978 fps

    123 Lapua Scenar HPBT (BC .547)

    14.5 bbl = 2486 fps
    16 bbl = 2505 fps
    24 bbl = 2650 fps

    Fortier's data was derived using an Oehler 35P chronograph 15 ft from the muzzle, 40 degrees F, 100 ft above sea level.


    6.5 GRENDEL GEL TEST REPORT

    Ballistic gelatin testing of select 6.5 Grendel loadings was performed this past Monday, May 8, 2006, and I've finally got my hands on the results. I've waited two years for this! CentCom tested one 6.5 Grendel load in August 2004, but, apparently, didn't feel the need to release the results for civilian or commercial use.

    Alexander Arms contracted this latest round of gel tests from Speer Law Enforcement representatives in order to have these tests serve as an experimental "control" for ballistics gelatin tests performed by other entities.

    Speer performed these tests according to the standard F.B.I. Protocols, as well as their standard in-house procedures. They use 6 x 6 x 16" blocks of ten percent ballistic gelatin, calibrated with a BB. It is interesting to note that Speer uses green dye instead of red to better delineate the temporary and permanent cavities; we conjecture it's for "politically correct" considerations.

    Alexander Arms tested four loads: (1) 120 Norma FMJ, (2) 120 Sierra MatchKing (SMK), (3) prototype 123 SMK, and (4) 90 Speer TNT. All tests were performed using production Alexander Arms Tactical 14.5 and Tactical 16 M4-style carbines at ranges of 50 and 100 yards. Here is a summary of the results:


    120 Norma FMJ

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    The 120 Norma FMJ, above, penetrated 16.5" before veering out the side of the block and impacting the support frame. No fragmentation was evident, but the slug is believed to have tumbled at about the 7" mark, with the maximum permanent cavity at the 11" mark. Lesions of more than 6" were created on the top and bottom block surfaces. The Alexander Arms Tactical 14.5 was used in the three 120 Norma FMJ photos shown here. Range: 50 yards. Impact velocity: 2405 fps.

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    Another shot of the 120 Norma FMJ.

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    Close-up of 120 Norma FMJ.

    120 Sierra MatchKing

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    The 120 Sierra MatchKing penetrated 3.25" before yawing and fragmenting. The Alexander Arms Tactical 16 carbine was used in the three 120 SMK photos shown here. Range: 100 yards. Impact velocity: 2383 fps. (Velocity from 24" test barrel was 2660 fps @ 49,800 psi.)

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    Maximum penetration of the 120 SMK was 19.5", maximum permanent cavity diameter was more than 6" with lesions running to block exterior surfaces. Depth to the maximum permanent cavity was 7.5". Bullet fragmented, with seven large pieces visible within the block. Jacket sections came to rest at 11.75" and 16.25", and the bullet core at 19.5".

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    Close-up of 120 SMK penetration neck before yaw.


    123 Sierra MatchKing Prototype

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    The prototype 123 SMK penetrated 2" before yawing and fragmenting. (The 123 SMK is not currently a Sierra catalog offering.) The Alexander Arms Tactical 14.5 carbine was used in the three 123 SMK photos shown here. Range: 50 yards. Impact velocity: 2385 fps. (Velocity from 24" test barrel was 2650 fps @ 49,500 psi.)

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    Maximum penetration of the 123 SMK was 16.2", maximum permanent cavity diameter was more than 6" with lesions running to block exterior surfaces. Depth to the maximum permanent cavity was 7". Bullet fragmented into multiple small fragments with jacket pieces visible at 11" and 13". Small core fragment was visible at maximum depth of 16.2"

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    Close-up of 123 SMK penetration neck before yaw.


    90 Speer TNT

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    The 90 Speer TNT performed as expected for a varmint bullet.


    Auto Glass

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    Entry hole of the 120 SMK through auto glass.


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    Impact of 120 SMK into ballistic gelatin after passing through auto glass.


    Summary

    These tests demonstrate the flexibility of the 6.5 Grendel cartridge in tactical scenarios. Each loading is a tool designed to perform a certain job. If you need penetration, use the 120 Norma FMJ. If you need a general-purpose tactical OTM with decent penetration of intermediate barriers yet with very good fragmentation, use the 120 SMK. If you want a long-range bullet that shoots like the 123 Lapua Scenar yet exhibits very early and explosive fragmentation, call for the 123 SMK.

    It's interesting that the 123 SMK, a bullet that rivals the 123 Lapua Scenar with its .547 BC, also proved to be the most violently fragmenting round of those tested (well, not counting the TNT). We had been led to believe that bullets that perform extremely well at long range would perform poorly at CQB in MOUT. However, testing now shows that the 123 SMK provides wicked fragmentation at CQB ranges with twice the lead mass of 5.56 NATO, as well as shooting flatter and drifting less than 7.62 NATO out to 1000 yards. This capability in one loading truly makes the 6.5 Grendel a unique tool in the AR15/M16/M4 tactical toolbox.

    I will update this report as more data comes in. It's unfortunate that the Wolf 6.5 Grendel ammunition did not arrive in time to test, so that will also have to wait until later.

    John
     
    Last edited: Dec 14, 2007
  4. Paul Revere

    Paul Revere OT Supporter

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    i read that no less than 30 minutes ago :eek3:

    :coold:
     
  5. TwistedMind

    TwistedMind New Member

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    cool, I think it will be a good adition to this forum
     
  6. TwistedMind

    TwistedMind New Member

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    Im never doing that again, its a pain in the ass trying to keep track of where you are LMAO

    Someone else is going to have to do 6.8
     
  7. Soybomb

    Soybomb New Member

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