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[ARCHIVED THREAD] - MEN 56 Grain M193 Accuracy (Page 1 of 2)
Posted: 7/2/2021 9:56:38 PM EDT
MEN 56 Grain M193 Accuracy Yes, you read that title correctly. The M193 ammunition manufactured by MEN (Metallwerk Elisenhütte GmbH) has a 56 grain bullet. “But Molon,” you say. “How can this be M193 if it doesn’t have a 55 grain bullet?” Well, if you look at the mil-spec drawing for the M193 projectile, you’ll see that the weight specification for the copper jacket of the bullet is 17.5 grains, with a tolerance of minus 1.0 grains. Also, the lead slug for the projectile has a weight specification of 38.5 grains, with a tolerance of minus 1.0 grains. Take the 17.5 grains for the jacket, add it to the 38.5 grains for the lead slug and we have a total weight for the projectile of 56 grains (with a total tolerance of minus 2.0 grains). So, as long as the bullet doesn’t weigh more than 56 grains (or less than 54 grains), it technically meets the weight specification for M193.  The 56 grain MEN M193 bullet is approximately 0.030” longer than a typical American manufactured M193 bullet.  This ammunition is loaded in brass cases with the annealing iris still visible. The case mouth has asphalt sealant and is crimped into the cannelure of the bullet. This ammunition is charged with “ball” powder.  Each red square in the grid below is 1/10th of an inch.  The case-head stamp of the lot of this ammunition that I tested reads: 5,56x45 MEN16 The primer pocket has a healthy dose of sealant. Strangely enough, the primer pockets are not crimped, which technically means this ammunition does not meet the US mil-spec for M193.  Accuracy The US accuracy specification for M193 cited in MIL-C-9963F is as follows: The average of the mean radii of all targets of the sample cartridges, fired at 200 yards, shall not exceed 2.0 inches. These averages are from 10-shot groups fired from machine rested, bolt-actioned, heavy test barrels. All things being equal this specification equates to a mean radius of 1 inch at 100 yards (the distance at which I tested this ammunition). I conducted an accuracy (technically, precision) evaluation of the MEN 56 grain M193 ammunition following my usual protocol. This accuracy evaluation used statistically significant shot-group sizes and every single shot in a fired group was included in the measurements. There was absolutely no use of any Group Reduction Techniques (e.g. fliers, target movement, Butterfly Shots). The shooting set-up will be described in detail below. As many of the significant variables as was practicable were controlled for. Also, a control group was fired from the test-rifle used in the evaluation using match-grade, hand-loaded ammunition; in order to demonstrate the capability of the barrel. Pictures of shot-groups are posted for documentation. All shooting was conducted from a concrete bench-rest from a distance of 100 yards (confirmed with a laser rangefinder.) The barrel used in the evaluation was free-floated. The free-float handguards of the rifle rested in a Sinclair Windage Benchrest, while the stock of the rifle rested in a Protektor bunny-ear rear bag. Sighting was accomplished via a Leupold VARI-X III set at 25X magnification and adjusted to be parallax-free at 100 yards. A mirage shade was used. Wind conditions on the shooting range were continuously monitored using a Wind Probe. The set-up was very similar to that pictured below.  The Wind Probe . . .  The test vehicle for this evaluation was one of my semi-automatic precision AR-15s with a 20” stainless-steel Lothar Walther barrel. The barrel has a 223 Wylde chamber with a 1:8” twist.    Prior to firing the MEN 56 grain M193, I fired a 10-shot control group using match-grade hand-loads topped with the Sierra 52 grain MatchKing. That group had an extreme spread of 0.59”.  Three 10-shot groups of the MEN 56 grain M193 were fired in a row with the resulting extreme spreads: 1.39” 1.35" 1.34” for a 10-shot group average extreme spread of 1.36”. The three 10-shot groups were over-layed on each other using RSI Shooting Lab to form a 30-shot composite group. The mean radius for the 30-shot composite group was 0.47”. (For those of you who might not be familiar with the mean radius, see the second post of this thread). The smallest 10-shot group (by mean radius) . . .  The 30-shot composite group . . .  Velocity The velocity specification for M193 as cited in MIL-C-9963F states: "The average velocity of the sample cartridges, conditioned at 72 degrees, plus or minus 2 degrees Fahrenheit (F), shall be 3165 feet per second (ft/sec), plus or minus 40 ft/sec, at 78 feet from the muzzle of the weapon. The standard deviation of the velocities shall not exceed 40 ft/sec." The velocity specification is from a 20” test barrel. Depending on multiple variables, this velocity specification equates to a muzzle velocity of approximately 3270 ft/sec, plus or minus 40 ft/sec. As an aside, after reading the above specification, some of you may be wondering, “Why 78 feet from the muzzle?” The answer to that question is that this specification is simply an historical hold-over from the days when “circuit” chronographs (e.g. Le Boulenge Chronograph and the Aberdeen Chronograph) were used at Aberdeen Proving Ground, Frankford Arsenal and Springfield Armory. These types of chronographs required a significant distance between their first and second screens to produce accurate results. As an example, when using the Boulenge Chronograph, the first screen of the chronograph was placed 3 feet in front of the muzzle and the second screen was placed 150 feet beyond the first screen. For those of you who might not be aware of the following fact; chronographs determine the velocity of the bullet at a point that is midway between the first and the second screen (i.e. not at the location of the first screen). Therefore, with the above spacing, the velocity of the bullet is determined for a point that is 75 feet from the first screen. So, add the three feet (from the muzzle to the first screen) to the 75 feet (the midway point of the screens) to obtain the “78 feet from the muzzle” distance.  I chronographed the MEN 56 grain M193 ammunition from a semi-automatic AR-15 with a chrome-lined, NATO chambered 20” Colt barrel with a 1:7” twist. Chronographing was conducted using an Oehler 35-P chronograph with “proof screen” technology. The Oehler 35P chronograph is actually two chronographs in one package that takes two separate chronograph readings for each shot and then has its onboard computer analyze the data to determine if there is any statistically significant difference between the two readings. If there is, the chronograph “flags” the shot to let you know that the data is invalid. There was no invalid data flagged during this testing. The velocity stated below is the muzzle velocity as calculated from the instrumental velocity using Oehler’s Ballistic Explorer software program. The string of fire consisted of 10 rounds over the chronograph.   Each round was single-loaded and cycled into the chamber from a magazine fitted with a single-load follower. The bolt locked-back after each shot allowing the chamber to cool in between each shot. This technique was used to mitigate the possible influence of “chamber-soak” on velocity data. Each new shot was fired in a consistent manner after hitting the bolt release. Atmospheric conditions were monitored and recorded using a Kestrel 4000 Pocket Weather Tracker.  Atmospheric conditions Temperature: 73 degrees F Humidity: 80% Barometric pressure: 30.02 inches of Hg Elevation: 950 feet above sea level The muzzle velocity for the 10-shot string of the MEN 56 grain M193 ammunition fired from the 20” Colt barrel was 3161 FPS with a standard deviation of 10 FPS and a coefficient of variation of 0.32%. For those of you who might not be familiar with the coefficient of variation (CV), it is the standard deviation, divided by the mean (average) muzzle velocity and then multiplied by 100 and expressed as a percentage. It allows for the comparison of the uniformity of velocity between loads in different velocity spectrums; e.g. 77 grain loads running around 2,650 fps compared to 55 grain loads running around 3,250 fps. For comparison, the mil-spec for M193 allows for a coefficient of variation of approximately 1.2%, while one of my best 77 grain OTM hand-loads, with a muzzle velocity of 2639 PFS and a standard deviation of 4 FPS, has a coefficient of variation of 0.15%.  … |
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A PRIMER ON THE MEAN RADIUS The mean radius is a method of measurement of the radial dispersion of shot-groups that takes into account every shot in the group. It provides a more useful analysis of the consistency of ammunition and firearms than the commonly used method of extreme spread. Mean radius as defined in Hatcher's Notebook “is the average distance of all the shots from the center of the group. It is usually about one third the group diameter (extreme spread)” for 10-shot groups. The ratio is actually closer to 3.2 x the mean radius = the extreme spread for 10-shot groups, depending on the sample size and the morphology of the particular groups sampled. To obtain the mean radius of a shot-group, measure the heights of all shots above the lowest shot in the group. Average these measurements. The result is the height of the center of the group above the lowest shot. Then in the same way, get the horizontal distance of the center from the shot farthest to the left. These two measurements will locate the group center. Now measure the distance of each shot from this center. The average of these measures is the mean radius. Once you get the hang of measuring groups using the mean radius it becomes very simple to do. While being very simple to do, it is also very time consuming. Modern software programs such as RSI Shooting Lab and On Target make determining the mean radius a snap. The picture below is a screen capture from RSI Shooting Lab. The red cross is the center of the group (a little high and right of the aiming point). The long red line shows the two shots forming the extreme spread or group size. The yellow line from the red cross to one of the shots is a radius. Measure all the radii and take the average to obtain the mean radius.  Mean Radius Demonstration Let’s say you fired a 5-shot group from 100 yards and the resulting target looks like this. (The X-ring measures 1.5” and the 10-ring measures 3.5”.)  The extreme spread of the group measures 2.83”, but we want to find the mean radius (or average group radius.) In order to find the mean radius we must first find the center of the group. By “eye-balling” the target most people would see that the group is centered to the left of the “X-ring” and probably a little high, but we need to find the exact location of the center of the group. Locating the Center of the Group The first step in finding the center of the group is to find the lowest shot of the group and draw a horizontal line through the center of that shot.  Next, find the left-most shot of the group and draw a vertical line through the center of that shot.  Now measure the distance from the horizontal line to the other four shots of the group that are above that line. Add those numbers together and divide by the total number of shots in the group (5).  2.50” + 1.03” + 2.01” + 1.30” = 6.84” Divide by 5 to get 1.37”. This number is the elevation component of the center of the group. Next we need to find the windage component of the center of the group. From the vertical line, measure the distance to the other four shots of the group that are to the right of the line. Add those numbers together and again divide by the total number of shots in the group (5).  1.76” + 2.54” + 0.45” + 1.19” = 5.94” Divide by 5 to get 1.19” This is the windage component of the center of the group. Finding the windage and elevation components of the center of the group is the most difficult part of this process. Once that is done the rest of the process is a piece of cake. Using the windage and elevation components, locate the position on the target that is 1.37” (elevation component) above the horizontal line and 1.19” (windage component) to the right of the vertical line. This location is the center of the group!  Determining the Mean Radius Now that we have located the position of the center of the group, the first step in determining the mean radius is to measure the distance from the center of the group to the center of one of the shots. This line is a single “radius”.  Now measure the distance from the center of the group to the center of each of the rest of the shots in the group. Add the measurements of all the radii together and then divide by the total number of shots in the group (5).  0.85” + 1.35” + 1.38” + 0.84” + 1.61” = 6.03” Divide by 5 to get 1.21”. This is the mean radius (or average group radius) of the group! Using the mean radius measurement to scribe a circle around the center of the group gives you a graphic representation of the mean radius. This shows the average accuracy of all the shots in the group. This demonstrates why the mean radius is much more useful than the extreme spread in evaluating the radial dispersion of our rifles and ammunition.  The table below will give you an idea of the relationship between the mean radius and extreme spread for 10-shot groups.  Here are some interesting quotes on the subject from old issues of American Rifleman. “Mean radius is the mean distance of bullet impacts from the center of the test group. It is used in government ammunition acceptance because it takes account of every shot and comes close to maximizing the test information. While there is no exact relationship between this measure and the simpler and more convenient group diameter, the 10-shot group diameter averages slightly over 3 times the mean radius.” "These examples illustrate the sensitiveness of the extreme spread to number of shots in the group. Indeed, as the table indicates, the measures made to only the outside shots of the group, e.g. the extreme spread, are very sensitive to number of shots, while the measures made to all the shots, e.g. the mean radius are far less so. It may be added that the latter measures are also less variable in their representation of the group; they are more efficient. This explains why the target testing of U.S. military rifle ammunition is by mean radius." … |
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As always, Thank You for sharing. IMHO, those are great groups for "Ball" ammo. MEN 56gr has also shot very well out of all my barrels. And have produced groups far better then typical US made 55gr "Ball" ammo. Looking forward to the velocity results. FWIW... I would like to see a thorough ballistic gel test from a 16" barrel. Just to see if the 56gr would fragment as "frequently" as typical US 55gr M193. On a side note, This MEN 56gr ammo has also been some of the cleanest burning ammo I have ever used. |
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MEN 2020 Catalog It's fun to see all the stuff we'll never get here |
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Thanks for sharing, I had not thought to look at a MEN Catalog. Very Interesting products. |
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Quoted: Given how the Europeans feel about "fragmenting" bullets, I would be very surprised if these fragmented at all. Looking forward to see if anyone does gel tests. Blue Falcon did last year. As you suspected, no fragmentation. https://m.youtube.com/watch?v=tHNX07Pb2jU&t=446s |
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Quoted: Blue Falcon did last year. As you suspected, no fragmentation. https://m.youtube.com/watch?v=tHNX07Pb2jU&t=446s Out of a 10.5" barrel @2600fps. The generally accepted min velocity for reliable fragmentation in US M193 is 2700fps. To get a baseline on a rounds performance, at least some of the shots need to be from a 20" barrel |
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Oddly enough, that catalog lists the bullet weight of their M193 load as 55 grains, but also as 3.6 grams, like on the box label for the ammunition that I tested. ... |
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Quoted: Oddly enough, that catalog lists the bullet weight of their M193 load as 55 grains, but also as 3.6 grams, like on the box label for the ammunition that I tested. ... Quoted: Oddly enough, that catalog lists the bullet weight of their M193 load as 55 grains, but also as 3.6 grams, like on the box label for the ammunition that I tested. ... I noticed that too. 3.6g converts to 55.556 gr |
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Some of the German bullets, especially NATO weight ones, have a brass disc in the base of the bullet, to cover the lead that would otherwise be exposed for, "environmental" reasons. These bullets are usually a grain heavier and possibly have the jacket shape or length adjusted to accommodate the additional disc. I don't know if they do it for 55 / 56 grain bullets. |
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Quoted: Some of the German bullets, especially NATO weight ones, have a brass disc in the base of the bullet, to cover the lead that would otherwise be exposed for, "environmental" reasons. These bullets are usually a grain heavier and possibly have the jacket shape or length adjusted to accommodate the additional disc. I don't know if they do it for 55 / 56 grain bullets. They don't.  ... |
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Yeah, I didn't think they would for the 55 grain bullets. The German military does have their NATO weight bullets closed off with brass now discs though. Low emission German military cartridge. https://www.men-defencetec.de/en/produkt/nato-ball-doppelkern-dm11/ Standard NATO weight bullet cartridge. https://www.men-defencetec.de/en/produkt/ball-m855-ss109/ So called M193 cartridge. https://www.men-defencetec.de/en/produkt/ball-weichkern-m193/ Another 62 grain bullet low emission cartridge. https://www.men-defencetec.de/en/produkt/ball-weichkern-dm41/ Quoted: Quoted: Some of the German bullets, especially NATO weight ones, have a brass disc in the base of the bullet, to cover the lead that would otherwise be exposed for, "environmental" reasons. These bullets are usually a grain heavier and possibly have the jacket shape or length adjusted to accommodate the additional disc. I don't know if they do it for 55 / 56 grain bullets. They don't. https://www.ar15.com/media/mediaFiles/28568/men_56_grain_m193_bullet_base_01-2016921.jpg ... |
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Quoted: Out of a 10.5" barrel @2600fps. The generally accepted min velocity for reliable fragmentation in US M193 is 2700fps. To get a baseline on a rounds performance, at least some of the shots need to be from a 20" barrel You mean you don't like apples to kumquats comparisons?  ... |
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I LOVE your data sets. No homo. Have you shot other M193 equivs? TAA and CBC? Stocks of other imports have gone away (Malaysian for their M16A1 Carbines, Guatemalan for Galils, I don't know what the Philippines shot, Koreans shot PMC/PMD. The Thais had both M16A1s and HKs. I think Prvi is still in production, maybe GGG. What do France [for the FAMAS] and Turkey produce? The UK's Radway Green generally sucked. I also have some RUAG and GECO brass). In ancient history, Bill Wylde shot Canadian M855-equivalent and said it was exceptional -- I don't know if they ever made 55-grain ball. |
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Quoted: I have not. I've been busy working on this (and a dozen other projects.) https://www.ar15.com/media/mediaFiles/28568/m193_clones_files_2021_d-2083037.jpg .. I understand. Probably only a little of the CBC/MEN 55gr M193 came in because it all sold out quick and hasnt been back. I think with US ammo prices where they are everyone is checking their old inventory over-seas and selling it to distributors here at 2X what they paid just a few years ago. Hopefully more foreign stuff will keep popping up. |
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MEN apparently is now head stamped CBC, who are their owners now. I know MEN brass was viewed as GECO/NORMA level quality. Nice heavy European brass with perfect flash holes. The (now) Brazilian owned company CBC brass (and overall ammo quality) I don't know if is the same or not, and am quite curious on that in fact. Im hopeful. https://centerfiresystems.com/product/2009-production-german-men-defense-m193-5.56mm-ammo-1000rd-case#product_detail  |
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My understanding is that German MEN ammo shipment to USA is a rare thing. Only surplus .308 or excess product. Most American (non-gov) orders go straight to CBC by defat CBC,is not men quality, is the primary source of American imports. Wouldn’t surprise me if CBC would sell us Brazilian made MEN to get a premium. That 2009 stuff is probably subcontracted ammo and it predates the companies merging I think. Most MEN capacity goes to the German gov. |
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Quoted: MEN apparently is now head stamped CBC, who are their owners now. I know MEN brass was viewed as GECO/NORMA level quality. Nice heavy European brass with perfect flash holes. The (now) Brazilian owned company CBC brass (and overall ammo quality) I don't know if is the same or not, and am quite curious on that in fact. Im hopeful. https://centerfiresystems.com/product/2009-production-german-men-defense-m193-5.56mm-ammo-1000rd-case#product_detail https://cdn9.coreware.com/cache/image-full-15519-cc02a4bb8a845a827ae06e5d8a4aff13.jpg You're looking at ammo that was loaded in 2009. All new production MEN for at least the last 4 years is stamped "MEN" |
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Quoted: I think this is subcontract ammo, not made in Germany. This is my assessment also. Likely CBC in Brazil filled a contract for MEN. I dont have any German MEN to compare it to but this CBC/MEN with "CBC 09" headstamp is holding under 2MOA with most of my 5 shot groups right at 1.5" at 100 yards in several guns. Only thing that outshot this stuff was the older Geco 55FMJ and some Italian made "red box" Fiocchi 55FMJ and they were 223 loadings not true 5.56. |
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Question, molon. Reading the specifications listed for m193 you stated this: “The specification is for a 20” barrel. Depending on multiple variables, this velocity specification equates to a muzzle velocity of approximately 3270 ft/sec, plus or minus 40 ft/sec.” The ammunition listed on the box states m193 but your recorded velocity is in the mid 3100s. Is this due to simply each nation defining what is m193 and being loose with the specs? |
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Quoted: Question, molon. Reading the specifications listed for m193 you stated this: “The specification is for a 20” barrel. Depending on multiple variables, this velocity specification equates to a muzzle velocity of approximately 3270 ft/sec, plus or minus 40 ft/sec.” The ammunition listed on the box states m193 but your recorded velocity is in the mid 3100s. Is this due to simply each nation defining what is m193 and being loose with the specs? If it doesn't meet the M193 specifications then it really isn't M193, so we have a category of ammunition sold on the commercial market that I usually refer to as an M193 clone. According to MEN's own catalog information they do produce a load that has the correct M193 velocity, but apparently they don't sell it to us lowly civilians. Odds are, their load that meets the true M193 velocity spec isn't as accurate as the slower load reviewed for this article.  ... |
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Quoted: This is my assessment also. Likely CBC in Brazil filled a contract for MEN. I dont have any German MEN to compare it to but this CBC/MEN with "CBC 09" headstamp is holding under 2MOA with most of my 5 shot groups right at 1.5" at 100 yards in several guns. Only thing that outshot this stuff was the older Geco 55FMJ and some Italian made "red box" Fiocchi 55FMJ and they were 223 loadings not true 5.56. I've since bought some of the newer MEN 56gr from SGAmmo (with the MEN 21 headstamp) and compared it with the MEN/CBC 09. As far as accuracy is concerned, some guns prefer one while some prefer the other. My Larue Stealth shot the CBC 09 a little better (best 5 shot group at 100 was 1.10" compared to 1.85" for MEN 21) while my PSA shot the MEN 21 better. I think the CBC may be a little faster also. |
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Chasing that 1 grain difference is kind of funny, as most don't realize that a good 223 round and 5.56 of the same company is likely to be identical in accuracy. Paul Harrell demonstrated it quite well: https://www.youtube.com/watch?v=BTgGhIcR_Mk&t=11s What matters more is what powder you use, how good the primer is, and metal consistency. Wolf has crap everything, but has bimetal jacket that actually penetrates better than regular FMJ, but accuracy is abysmal. That 1 grain means zero, if manufacturer focuses at other parts of the bullet. Steel case ammo for an example sucks, not because of it's casing, but because Russia doesn't even want to use flash suppressant in the gunpowder, so you see fireballs for days. Manufacturing makes more difference, than 223 vs 556 or 55 grain vs 56 or even 62 grain. If manufacturing sucks, you may have better accuracy with 223 versus bad quality 5.56 round. At this point this 56 grain is a huge gimmick to me. I literally weighed my rounds in possession, and here is what I gathered: Australian Outback 12.1 grams 62 grain, 5.56, FMJ - Excellent ammo by the way, Australian Outback claimed one of the lowest co-efficient of bullet deviation on the market, as far as I could tell they are claiming to be at the top rank of the industry, not sure of the claim, but for me the ammo was very accurate for a long range shots and close shots as well, out of the good barrel of course. American Eagle 11.5 grams 55 grain, .223, FMJ PMC Bronze 11.3 grams 55 grain, .223, FMJ PMC X-Tac 11.5 grams 55 grain, 5.56, FMJ - Pretty good accuracy, far from perfect PMC X-Tac 11.9 grams 62 grain, 5.56, Green Tip - Not the best accuracy, but easily hits steel at 180 yards with consistency, eats AR500 steel very quickly. Pretty hot ammo from what I noticed, moves fast, sparks on steel hard. But all that weight means nothing, if manufacturing behind it sucks. |
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Quoted: Herp . . . derp . . . and more herp. Dunning–Kruger effect on full display. Quoted: Chasing that 1 grain difference is kind of funny Your post is the only laughable thing in this thread because nobody is “chasing a 1 grain difference” in bullet weight. What people are chasing, is accuracy/precision and if you had the slightest clue what you were talking about, you would know that the German manufactured MEN M193 is one of the most accurate M193 clones ever offered for sale on the commercial market. If you had actually even read the statistically significant data posted in this thread, you would have known that. Quoted: most don't realize that a good 223 round and 5.56 of the same company is likely to be identical in accuracy. Some don’t realize how utterly clueless they are. Your statement is pure bullshit and easily proven false using statistically significant groups sizes of quality 5.56mm and 223 Remington loads from the same company, as shown below with the GECO ammunition. Quoted: Paul Harrell demonstrated it quite well: https://www.youtube.com/watch?v=BTgGhIcR_Mk&t=11s No, he didn't. There is sooooo much retardation in that video that I’m not even going to waste my time pointing out every thing that is wrong in it. The piss-ant, statistically insignificant couple of 5-shot groups that he fired mean exactly jack and shit for determining the radial dispersion of ammunition. He even admitted in the video that he can’t shoot consistently, so his “findings” mean squat. Oh, and if he’s going to talk about case capacity, maybe he should actually measure case capacities.  Quoted: What matters more is what powder you use, how good the primer is, More stupidity. The single most import component in a load is the bullet. Extensive testing at Lake City has shown that the bullet accounts for 60% of the accuracy of a load. Quoted: At this point this 56 grain is a huge gimmick to me. Wow! The amount of first-hand, statistically significant data that you collected, analyzed and posted to support that claim is amazing! Oh wait . . . you didn’t do any of that. You just pulled some shit out of your ass and pretended that it’s a fact. Quoted: That 1 grain means zero Logic fallacy: straw man. Quoted: I literally weighed my rounds in possession As opposed to figuratively weighing rounds in someone else’s possession? Quoted: here is what I gathered: Australian Outback 12.1 grams What in the actual fuck does the complete cartridge weight of a 62 grain FMJ load have to do with the accuracy and velocity of MEN M193? Before dumping any more of your ignorant bullshit in this thread, why don’t you try actually educating yourself. You can start here . . . Molon Reference Links … GECO 223 Remington 55 Grain FMJ Target  This is not your father’s 55 grain FMJ ammunition. For starters, the 55 grain FMJ projectile loaded in this ammunition has a groove cannelure, instead of a rolled cannelure that is typically found on 55 grain FMJ bullets. Secondly, the boat-tail on the GECO bullet is longer than that found on typical 55 grain FMJ bullets.  The GECO bullets have some of the most uniform bases I’ve ever seen on bullets in this category.  This ammunition is loaded in brass cases that have the annealing iris still visible. The cases have sealed primer pockets. The primer pockets are crimped with three “stab” crimps. The head-stamp reads: “ GECO .223 Rem. ”. The case-mouths are also crimped and sealed. The ammunition is charged with a short-cut extruded powder.  (The individual squares in the red grid pictured below are one-tenth of an inch.)  Velocity I chronographed the GECO 223 Remington 55 grain FMJ Target ammunition from a semi-automatic AR-15 with a chrome-lined, NATO chambered, 20” Colt M16A2 barrel. Chronographing was conducted using an Oehler 35-P chronograph with “proof screen” technology. The Oehler 35P chronograph is actually two chronographs in one package that takes two separate chronograph readings for each shot and then has its onboard computer analyze the data to determine if there is any statistically significant difference between the two readings. If there is a difference, the chronograph “flags” the shot to let you know that the data is invalid. There was no invalid data flagged during this testing. The velocity stated below is the muzzle velocity as calculated from the instrumental velocity using Oehler’s Ballistic Explorer software program. The string of fire consisted of 10 rounds over the chronograph. Each round was single-loaded and cycled into the chamber from a magazine fitted with a single-load follower. The bolt locked-back after each shot allowing the chamber to cool in between each shot. This technique was used to mitigate the possible influence of “chamber-soak” on velocity data. Each new shot was fired in a consistent manner after hitting the bolt release. Atmospheric conditions were monitored and recorded using a Kestrel 4000 Pocket Weather Tracker. Atmospheric conditions Temperature: 78 degrees F Humidity: 33% Barometric pressure: 30.05 inches of Hg Elevation: 950 feet above sea level The muzzle velocity for the 10-shot string of the GECO 223 Remington 55 grain FMJ Target ammunition fired from the 20” Colt barrel was 3084 FPS with a standard deviation of 26 FPS and a coefficient of variation of 0.84%. Accuracy I conducted an accuracy (technically, precision) evaluation of the GECO 223 Remington 55 grain FMJ Target ammunition following my usual protocol. This accuracy evaluation used statistically significant shot-group sizes and every single shot in a fired group was included in the measurements. There was absolutely no use of any group-reduction techniques (e.g. fliers, target movement, butterfly shots). The shooting set-up will be described in detail below. As many of the significant variables as was practicable were controlled for. Also, a control group was fired from the test-rifle used in the evaluation using match-grade, hand-loaded ammunition; in order to demonstrate the capability of the barrel. Pictures of shot-groups are posted for documentation. All shooting was conducted from a concrete bench-rest from a distance of 100 yards (confirmed with a laser rangefinder.) The barrel used in the evaluation was free-floated. The free-float handguards of the rifle rested in a Sinclair Windage Benchrest, while the stock of the rifle rested in a Protektor bunny-ear rear bag. Sighting was accomplished via a Leupold VAR-X III set at a magnification of 25X and adjusted to be parallax-free at 100 yards. A mirage shield was attached to the objective-bell of the scope. Wind conditions on the shooting range were continuously monitored using a Wind Probe. The set-up was very similar to that pictured below.  The Wind Probe. The test vehicle for this evaluation was one of my semi-automatic precision AR-15s with a 20” stainless-steel Lothar Walther barrel. The barrel has a 223 Wylde chamber with a 1:8” twist. Prior to firing the GECO 223 Remington 55 grain FMJ Target ammunition, I fired a 10-shot control group using a hand-load topped with the Sierra 77 grain MatchKing. That group had an extreme spread of 0.81”.  Three 10-shot groups of the GECO 223 Remington 55 grain FMJ Target ammunition were fired in a row with the resulting extreme spreads: 1.71” 1.06” 1.52” for a 10-shot group average extreme spread of 1.43”. The three 10-shot groups were over-layed on each other using RSI Shooting Lab to form a 30-shot composite group. The mean radius for the 30-shot composite group was 0.47”. The smallest 10-shot group . . .  The 30-shot composite group . . .  ….. GECO 5.56x45mm 55 Grain FMJ  This ammunition appears to be loaded with the same 55 grain FMJ projectile that is found in the GECO 223 Remington 55 Grain FMJ Target ammunition. The 55 grain FMJ projectile loaded in this ammunition has a groove cannelure, instead of a rolled cannelure that is typically found on 55 grain FMJ bullets. The boat-tail on the GECO bullet is longer than that found on typical 55 grain FMJ bullets and the GECO bullets have some of the most uniform bases I’ve ever seen on bullets in this category. This ammunition is loaded in brass cases that have the annealing iris still visible. The cases have sealed primer pockets. The primer pockets are crimped with three “stab” crimps. The case-mouths are also crimped and sealed. The ammunition is charged with a ball powder. The head-stamp reads: “ T 5.56 x 45 ”.  (The individual squares in the red grid pictured below are one-tenth of an inch.)  Velocity I chronographed the GECO 5.56x45mm 55 grain FMJ ammunition from a semi-automatic AR-15 with a chrome-lined, NATO chambered, 20” Colt M16A2 barrel. Chronographing was conducted using an Oehler 35-P chronograph with “proof screen” technology. The Oehler 35P chronograph is actually two chronographs in one package that takes two separate chronograph readings for each shot and then has its onboard computer analyze the data to determine if there is any statistically significant difference between the two readings. If there is a difference, the chronograph “flags” the shot to let you know that the data is invalid. There was no invalid data flagged during this testing. The velocity stated below is the muzzle velocity as calculated from the instrumental velocity using Oehler’s Ballistic Explorer software program. The string of fire consisted of 10 rounds over the chronograph. Each round was single-loaded and cycled into the chamber from a magazine fitted with a single-load follower. The bolt locked-back after each shot allowing the chamber to cool in between each shot. This technique was used to mitigate the possible influence of “chamber-soak” on velocity data. Each new shot was fired in a consistent manner after hitting the bolt release. Atmospheric conditions were monitored and recorded using a Kestrel 4000 Pocket Weather Tracker. Atmospheric conditions Temperature: 78 degrees F Humidity: 33% Barometric pressure: 30.05 inches of Hg Elevation: 950 feet above sea level The muzzle velocity for the 10-shot string of the GECO 5.56x45m 55 grain FMJ ammunition fired from the 20” Colt barrel was 3276 FPS with a standard deviation of 22 FPS and a coefficient of variation of 0.67%. Accuracy I conducted an accuracy (technically, precision) evaluation of the GECO 5.56x45mm 55 grain FMJ ammunition following my usual protocol. This accuracy evaluation used statistically significant shot-group sizes and every single shot in a fired group was included in the measurements. There was absolutely no use of any group-reduction techniques (e.g. fliers, target movement, butterfly shots). The shooting set-up will be described in detail below. As many of the significant variables as was practicable were controlled for. Also, a control group was fired from the test-rifle used in the evaluation using match-grade, hand-loaded ammunition; in order to demonstrate the capability of the barrel. Pictures of shot-groups are posted for documentation. All shooting was conducted from a concrete bench-rest from a distance of 100 yards (confirmed with a laser rangefinder.) The barrel used in the evaluation was free-floated. The free-float handguards of the rifle rested in a Sinclair Windage Benchrest, while the stock of the rifle rested in a Protektor bunny-ear rear bag. Sighting was accomplished via a Leupold VAR-X III set at a magnification of 25X and adjusted to be parallax-free at 100 yards. A mirage shield was attached to the objective-bell of the scope. Wind conditions on the shooting range were continuously monitored using a Wind Probe. The set-up was very similar to that pictured below. The Wind Probe. The test vehicle for this evaluation was one of my semi-automatic precision AR-15s with a 20” stainless-steel Lothar Walther barrel. The barrel has a 223 Wylde chamber with a 1:8” twist. Prior to firing the GECO 223 Remington 55 grain FMJ Target ammunition, I fired a 10-shot control group using a hand-load topped with the Sierra 77 grain MatchKing. That group had an extreme spread of 0.81”. Three 10-shot groups of the GECO 5.56x45mm 55 grain FMJ ammunition were fired in a row with the resulting extreme spreads: 2.55” 2.09” 2.19” for a 10-shot group average extreme spread of 2.28”. The three 10-shot groups were over-layed on each other using RSI Shooting Lab to form a 30-shot composite group. The mean radius for the 30-shot composite group was 0.79”. The smallest 10-shot group . . .  The 30-shot composite group . . .  Lastly, for any Internet Commandos in our viewing audience tonight, here’s a pic of a sub-half-MOA group of the GECO ammunition fired from 100 yards. The group has an extreme spread of 0.46”.  ..... |
 Not sure how I missed this thread previously!!Great info Molon, as always. I stocked up on this ammo when it was cheap at SG Ammo. Glad to see it's good stuff!  eta: picture of what I bought, I didn't catch before that it says 56 grains on the box! Eta 2: I love the warning "Keep out of reach of incompetent people" lol! |
[ARCHIVED THREAD] - MEN 56 Grain M193 Accuracy (Page 1 of 2)
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