Posted: 8/18/2004 5:06:07 AM EST
[Last Edit: 8/18/2004 6:17:22 AM EST by Grendelizor]
Last week the 6.5 Grendel participated in terminal ballistics tests conducted in accordance with FBI standards. The tests were observed by an evenly mixed crowd of law enforcement and military professionals, some of whom had delayed the testing until they could fly in from various parts of the world to attend the proceedings. The sponsoring agencies will not allow any of the photos or high-speed video to be published. They are not really interested in impressing the general public with their test data results. I know this disappoints many of you and I, too, am disappointed. Nevertheless, "inquiring minds want to know" as much as they can about the intermediate cartridge debate and so I'm presenting my hastily scribbled notes. Again, note: My report is only a quick synopsis; the results reported here are neither detailed nor extensive, nor can I offer photographic and video evidence, which the sponsoring agencies have required not be released.
The 6.5 Grendel was fired through the intermediate barriers specified by FBI protocol into calibrated gel blocks, sized 8 x 8 x 16 inches, both at close range and at 500 yards. Only the 144gr Lapua FMJBT bullet was used; this audience had no interest in OTM bullets, due to "hyper" sensitivities regarding international law and anything that could possibly be construed as a hollow-point.
The FBI tests as described by the FBI follow. My brief notes on the 6.5 Grendel's performance are interspersed within. My source for the FBI protocols is a website: http://www.seark.net/~jlove/fbitest.htm.
"After extensive research and consultation, the FBI established that a handgun bullet must consistently penetrate a minimum of 12 inches of tissue in order to reliably penetrate vital organs within the human target regardless of the angle of impact or intervening obstacles such as arms, clothing, glass, etc. Penetration of 18 inches is even better. Given minimum penetration, the only means of increasing wound effectiveness is to enlarge the permanent cavity. This increases the amount of vital tissues with a marginally placed shot, and increases the potential for quicker blood loss. This is important because, with the single exception of damaging the central nervous system, the ONLY way to force incapacitation upon an unwilling adversary is to cause enough blood loss to starve the brain of its oxygen and/or drop blood pressure to zero. This takes time, and the faster hemorrhage can occur the better."
"The FBI ammunition test protocol is a series of practically oriented tests to measure a bullet's ability to meet these performance standards. The result is an assessment of a bullet's ability to inflict effective wounds after defeating various intervening obstacles commonly present in law enforcement shootings. The overall results of a test are thus indicative of that specific cartridge's suitability for the wide range of conditions in which law enforcement officers engage in shootings."
"The test media used by the FBI to simulate living tissue is 10% ballistic gelatin (Kind & Knox 250-A), mixed by weight. The gelatin is stored at 4x Centigrade (39.2x Fahrenheit) and shot within 20 minutes of being removed from the refrigerator. The temperature of the gelatin is critical, because penetration changes significantly with temperature. This specific gelatin mix was determined and calibrated by the U.S. Army Wound Ballistics Research Laboratory, Presidio of San Francisco, to produce the same penetration results as that obtained in actual living tissue. Each gelatin block is calibrated before use to ensure its composition is within defined parameters. The gelatin blocks for handgun rounds are approximately six inches square and 16 inches long. As necessary, additional blocks are lined up in contact with each other to ensure containment of the bullet's penetration. Each shot's penetration is measured to the nearest 0.25 inch. The projectile is recovered, weighed and measured for expansion by averaging its greatest diameter with its smallest diameter."
Let me jump in here with some notes that have been brought to my attention. These FBI tests are specifically constructed to evaluate HANDGUN projectiles and are not, strictly speaking, calibrated to rifle projectiles. With weapons in the class of the 6.5 Grendel the best correlation is only about 64%. Calibrated gelatin was and is only intended to be a representative protocol to establish the relative performance of projectiles. The gelatin is rarely representative of any particular tissue found within a wound track, but rather is a good approximation to the overall average tissue traversed.
"The ammunition test protocol using this gelatin is composed of eight test events. In each test event, five shots are fired. A new gelatin block and new test materials are used for each individual shot. The complete test consists of firing 40 shots. Each test event is discussed below in order."
"All firing in these eight test events is done with a typical service weapon representative of those used by law enforcement. The weapon used is fully described in each test report."
"Test Event l: Bare Gelatin. The gelatin block is bare and shot at a range of ten feet measured from the muzzle to the front of the block. This test event correlates FBI results with those being obtained by other researchers, few of whom shoot into anything other than bare gelatin. It is common to obtain the greatest bullet expansion in this test. Rounds which do not meet the standards against bare gelatin tend to be unreliable in the more practical test events that follow."
6.5 GRENDEL RESULTS TEST 1: The 6.5 Grendel was not shot into bare gelatin for this audience.
"Test Event 2: Heavy Clothing. The gelatin block is covered with four layers of clothing: One layer of cotton T-Shirt material (48 threads per inch); one layer of cotton shirt material (80 threads per inch); a 10-ounce down comforter in cambric shell cover (232 threads per inch); and one layer of 13 ounce cotton denim (50 threads per inch). This simulates typical cold weather wear. The block is shot at ten feet, measured from the muzzle to the front of the block."
6.5 GRENDEL RESULTS, TEST 2: It was difficult to establish the onset of bullet yaw, but the yaw was fully established between 5 and 7 inches. The permanent cavity was difficult to establish because the round split the block from top to bottom. (Theoretically, this would invalidate the results and does not allow the extrapolation that with larger gelatin blocks the result will be a cavity of 8 inches or greater.) They couldn't gather all the fragments, because the larger pieces exited the top rear of the block; the smaller fragments of the long bullet averaged about 30-40 grains. The fragments tended to stay in larger chunks, rather than becoming sand-like granules.
"Test Event 3: Steel. Two pieces of 20-gauge, hot-rolled steel with a galvanised finish are set three inches apart. The steel is in six inch squares. The gelatin block is covered with light clothing and placed 18 inches behind the rear most piece of steel. The shot is made at a distance of 10 feet measured from the muzzle to the front of the first piece of steel. Light clothing is one layer of cotton T-Shirt material and one layer of cotton shirt material, and is used in all subsequent test events. The steel is the heaviest gauge steel commonly found in automobile doors. This test simulates the weakest part of a car door. In all car doors, there is an area, or areas, where the heaviest obstacle is nothing more than two pieces of 20 gauge steel."
6.5 GRENDEL RESULTS, TEST 3: The 6.5 Grendel passed this phase of the evaluation. By saying "passed" we mean that after the barrier it penetrated into the gel block "a minimum of 12 inches."
"Test Event 4: Wallboard. Two pieces of half-inch standard gypsum board are set 3.5 inches apart. The pieces are six inches square. The gelatin block is covered with light clothing and set 18 inches behind the rear most piece of gypsum. The shot is made ten feet, measured from the muzzle to the front surface of the first piece of gypsum. This test event simulates a typical interior building wall."
6.5 GRENDEL RESULTS, TEST 4: The 6.5 Grendel passed. Remember, we're talking about a 144gr FMJBT rifle bullet, not a handgun round.
"Test Event 5: Plywood. One piece of three-quarter inch AA fir plywood is used. The piece is six inches square. The gelatin block is covered with light clothing and set 18 inches behind the rear surface of the plywood. The shot is made at ten feet, measured from the muzzle to the front surface of the plywood. This test event simulates the resistance of typical wooden doors or construction timbers."
6.5 GRENDEL RESULTS, TEST 5: Like many other tests, the 6.5 Grendel easily penetrated and the bullet was lost out the top of the gel block. I know it's boring to keep saying "it also passed this test," but consider that certain 5.56 rifle bullets do not pass, so it's not always a given that a rifle bullet will pass these handgun tests.
"Test Event 6: Automobile Glass. One piece of A. S. I. one-quarter inch laminated automobile safety glass measuring l5 x l8 inches is set at an angle of 45 degrees to the horizontal. The line of bore of the weapon is offset 15 degrees to the side, resulting in a compound angle of impact for the bullet upon the glass. The gelatin block is covered with light clothing and set 18 inches behind the glass. The shot is made at ten feet, measured from the muzzle to the center of the glass pane. This test event with its two angles simulates a shot taken at the driver of a car from the left front quarter of the vehicle, and not directly in front of it."
6.5 GRENDEL RESULTS, TEST 6: These results were interesting in that the bullet path didn't curve as in previous tests. After penetrating the glass, the slug penetrated 18-19" into the gelatin. Yaw was fully established earlier than some of the lighter barriers, at about the 3-4" mark. The front of the jacket was stripped off and about 60 grains of lead core remained attached to the rear.
"Test Event 7: Heavy Clothing at 20 yards. This event repeats Test Event 2 but at the range of 20 yards, measured from the muzzle to the front of the gelatin. This test event assesses the effects of increased range and consequently decreased velocity."
6.5 GRENDEL RESULTS, TEST 7: I don't know if they performed this test with heavy clothing, but a test with light clothing was done at 500 yards with passing results. Remember, this rifle bullet loses very little velocity at long range due to its high ballistic coefficient (advertised .636).
"Test Event 8: Automobile Glass at 20 yards. This event repeats Test Event 6 but at a range of 20 yards, measured from the muzzle to the front of the glass, and without the 15 degree offset. This shot is made from straight in front of the glass, simulating a shot at the driver of a car bearing down on the shooter."
6.5 GRENDEL RESULTS, TEST 8: Again, the 6.5 Grendel passed this both at 20 yards and at 500 yards distance.
SUMMARY: The 144gr FMJBT Lapua exhibited both yaw and fragmenting, with the fragments tending to stay in larger pieces, making this almost a de facto triplex round. And the testers didn't even want to touch the 123gr Lapua Scenar, which is a match bullet giving very aggressive fragmentation. I'm sure this won't be the last word in 6.5 Grendel testing.
What have these tests proved? That the 6.5 Grendel is an awesome gelatin killer! The work performed in this series simply indicates that the 6.5 Grendel is worth further examination. What is the future? The sponsoring agencies have valid data that they have personally witnessed and participated in for review against their requirements.
6.5 Grendel: AR10 Soul in an AR15 Body
Ahhh... can we rename it the 6.5 Gelatin Killer - much better than Grendel!
Seriously this is high on the to get list... Just need to find the right mix of builder, barrel length, options...
I just realized that Grendel is the main in character in Beowulf. And there are two Ar-15 uppers with calibers that bear these names. Now back to regularly scheduled topic.
And both from the same manufacturer! Who'd a thunk it
They have been using Calibrated gelatin for 20 years while testing RIFLE bullets. Works just as well with rifle bullets as it does with handgun bullets.
Fackler, Roberts, and others have long since shown this.
BTW I was looking at Alexander Arms website and couldn't find the answer to two technical questions I have on this round.
1) Does it use a standard AR-15 bolt (the case is a larger diameter than 5.56, but the photo I had was bad and couldn't tell if it used a smaller rim)?
2) Does the round feed reliably from standard AR-15 magazines?
Thanks for any input.
i still want 6.8... but if i have to i'll use 6.5...
I don't know much about this round but I am pretty sure that
1. It uses a 7.62x39 bolt.
2. They have 10 round mags available now and surely after the sunset will have 25 or 30 rounders available. I think just like the 6.8 SPC they don't work very well from stock 5.56 mags.
I highly recommend anyone interested in this subject carefully read the presentation noted above. The KPP’s on slide #11 and the illustration of an ideal rifle wound profile on slide #12 are very important in understanding the desirable projectile terminal performance characteristics for maximizing the incapacitation effects of rifle ammunition.
Once you begin to understand this subject, slide #16 vividly illustrates the terminal performance advantages of 6.8 mm compared to the best current 5.56 mm ammunition, especially when used in shorter barrel weapons like the M4 and CQB-R…
Slide #15 illustrates the crucial importance of velocity for 5.56 mm FMJ ammunition and why terminal effectiveness is so dramatically reduced as one moves from M16 to M4 to CQB-R; slide #17 describes some of the trade-offs associated with this dilemma. If your mission requires a short barrel carbine, the 6.8 mm offers far better terminal performance, without sacrificing the ergonomics of the M4/CQB-R. When used with the right ammunition, compact 7.62x51 mm systems offer impressive terminal performance, but at the price of increased size and weight of the rifle and ammo.
Since Dr. Fackler’s groundbreaking research in the mid to late 1980’s, properly conducted gelatin testing for rifle ammunition has yielded very accurate and predictable results. I am unaware of any published research that supports the statement, “With weapons in the class of the 6.5 Grendel the best correlation is only about 64%.”
While you can get away with smaller gelatin blocks for handguns and 5.56 mm, it is important to use adequate size blocks for larger calibers—we use blocks of approximately 10 x 14 x 20 inches for rifle testing.
The test results described above reveal some of the yaw issues associated with 6.5 mm projectiles, as was discovered during SPC testing. Hopefully the information in the first post on this thread should help illuminate why 6.5 mm was not chosen for the SPC. Nonetheless, the 6.5 Grendel appears to be an interesting cartridge, especially for match and hunting use. I look forward to seeing more test results, especially out of 12-16 inch barrel lengths, to assess its utility for CQB. I suspect the 123 gr Lapua Scenar performance may be more interesting…
FWIW, a 6.8 mm of the same FMJ bullet construction will also pass all the FBI test protocols in the same manner as the testing above; if bullet construction is changed to a fragile OTM, then some of the tests, like auto glass, can be more challenging. As mentioned, 5.56 mm loads can have more problems with some of these test events. Moving to a good 7.62x51 mm load resolves any doubts…
[Edited to make the link hot. -Troy]
Being a reloader, I went through this thought process as well.
The 6.5 is a ballistically superior bullet and has the potential for longer distance accuracy. The 6.8 has (or had) the support of the gov't, so I can see how that would be appealing to some.
So my choice would be the 6.5 Grendel, but I don't care much for the configurations presently available and the $875 minimum price tag for just an upper isn't sitting well with me either. I guess if I want to play, I'll have to pay.