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[ARCHIVED THREAD] - USMC Gets the Silver Bullet (Page 1 of 2)
Posted: 2/3/2015 12:31:10 AM EDT
Mk318 Mod1 with the Silver Bullet.
Interview: SAL FANELLI,supervising engineer for Infantry Weapons Systems at MCSC "About this time the issue about environmentally friendly green ammo came up and we had to take a look to see if it was possible to replace the lead and still meet the specification. We found that we could replace the lead with copper, stretching the jacket around ever so slightly so it allowed us to crimp the nose even more. With that, the ballistic coefficient went up allowing the round to fly more efficiently through air with a better trajectory. Now it’s a ballistic match to the stock off-the-shelf reticle patterns that the Marine Corps uses, like the Trijicon ACOG sights. We named the improved round the Mk318 Mod1."
"Since we were worried about confusion with the Mk262, we had to take another look at the color of the tip. Every color was taken except for solid silver so we decided to nickel plate the entire projectile. As we now jokingly say, “All Marines will have silver bullets.” That round hasn’t been fielded yet, and a potential production contract is in the future. I can just see the Marines out there polishing bullets." http://www.sadefensejournal.com/wp/?p=2879 |
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it sounds like they gimped the Mk318 for the sake of being green. going from a lead core to a copper one is going to mean that its not going to fragment at all most likely. one of their bullet points for an effective round was to reduce fragmentation  The Barnes X bullet does not fragment at all and it is one lethal SOB. |
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The Barnes X bullet does not fragment at all and it is one lethal SOB. Quoted:
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it sounds like they gimped the Mk318 for the sake of being green. going from a lead core to a copper one is going to mean that its not going to fragment at all most likely. one of their bullet points for an effective round was to reduce fragmentation The Barnes X bullet does not fragment at all and it is one lethal SOB. Because it expands? |
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Because it expands? Quoted:
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it sounds like they gimped the Mk318 for the sake of being green. going from a lead core to a copper one is going to mean that its not going to fragment at all most likely. one of their bullet points for an effective round was to reduce fragmentation The Barnes X bullet does not fragment at all and it is one lethal SOB. Because it expands? You wouldn't be implying that expanding bullets may be outlawed according to the Hague convention (even though the US did not sign it), would you? |
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Quoted: Um. Okay. Federal has been nickel plating bullets for awhile now. Yep.... I prefer mine with the "Disco Tip".... Aka TTBBC.  Fudds (per the Arfcom definition) have actually killed more stuff than tactical dirt shooters, and are a good source of info on bullets that have good terminal performance.  Hunting bullets will alway be superior to crap that may or may not fragment, because they are engineered to expand within a certain criteria. This beats "I hope it does" which lies outside of the engineered design..... Every.... Damn.... Time. |
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Yep.... I prefer mine with the "Disco Tip".... Aka TTBBC. http://i651.photobucket.com/albums/uu240/Skg_Mre_Lght/2009529-fedpremtro_ms-300x168_zpsra7pzjkx.jpg Fudds (per the Arfcom definition) have actually killed more stuff than tactical dirt shooters, and are a good source of info on bullets that have good terminal performance.
Hunting bullets will alway be superior to crap that may or may not fragment, because they are engineered to expand within a certain criteria. This beats "I hope it does" which lies outside of the engineered design..... Every.... Damn.... Time. Quoted:
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Um. Okay. Federal has been nickel plating bullets for awhile now. Yep.... I prefer mine with the "Disco Tip".... Aka TTBBC. http://i651.photobucket.com/albums/uu240/Skg_Mre_Lght/2009529-fedpremtro_ms-300x168_zpsra7pzjkx.jpg Fudds (per the Arfcom definition) have actually killed more stuff than tactical dirt shooters, and are a good source of info on bullets that have good terminal performance.
Hunting bullets will alway be superior to crap that may or may not fragment, because they are engineered to expand within a certain criteria. This beats "I hope it does" which lies outside of the engineered design..... Every.... Damn.... Time.
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Yep.... I prefer mine with the "Disco Tip".... Aka TTBBC. http://i651.photobucket.com/albums/uu240/Skg_Mre_Lght/2009529-fedpremtro_ms-300x168_zpsra7pzjkx.jpg Quoted:
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Um. Okay. Federal has been nickel plating bullets for awhile now. Yep.... I prefer mine with the "Disco Tip".... Aka TTBBC. http://i651.photobucket.com/albums/uu240/Skg_Mre_Lght/2009529-fedpremtro_ms-300x168_zpsra7pzjkx.jpg wish in one hand, shit in the other..... |
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Quoted: wish in one hand, shit in the other..... Quoted: Quoted: Quoted: Um. Okay. Federal has been nickel plating bullets for awhile now. Yep.... I prefer mine with the "Disco Tip".... Aka TTBBC. http://i651.photobucket.com/albums/uu240/Skg_Mre_Lght/2009529-fedpremtro_ms-300x168_zpsra7pzjkx.jpg wish in one hand, shit in the other..... Meaning?
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Meaning? Quoted:
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Um. Okay. Federal has been nickel plating bullets for awhile now. Yep.... I prefer mine with the "Disco Tip".... Aka TTBBC. http://i651.photobucket.com/albums/uu240/Skg_Mre_Lght/2009529-fedpremtro_ms-300x168_zpsra7pzjkx.jpg wish in one hand, shit in the other..... Meaning? Meaning that the projectile that you posted a picture of isn't available in a 5.56mm/223 Remington load, nor as a .224 reloading component. (since the topic of this thread is the 5.56mm MK318 Mod 1 load) |
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Quoted: Meaning that the projectile that you posted a picture of isn't available in a 5.56mm/223 Remington load, nor as a .224 reloading component. (since the topic of this thread is the 5.56mm MK318 Mod 1 load) Quoted: Quoted: Quoted: Quoted: Quoted: Um. Okay. Federal has been nickel plating bullets for awhile now. Yep.... I prefer mine with the "Disco Tip".... Aka TTBBC. http://i651.photobucket.com/albums/uu240/Skg_Mre_Lght/2009529-fedpremtro_ms-300x168_zpsra7pzjkx.jpg wish in one hand, shit in the other..... Meaning? Meaning that the projectile that you posted a picture of isn't available in a 5.56mm/223 Remington load, nor as a .224 reloading component. (since the topic of this thread is the 5.56mm MK318 Mod 1 load) Doesn't matter. There are other bonded, and superior, hunting bullets available as components and factory stuff. The fine balance is accuracy vs performance. Ballistics gel is a good indicator, but should never supercede real world performance. My statement still stands. |
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Quoted: And, since this is an ATK product, the bullet is probably a plated X bullet, or an untipped TBBC. Fully agreed.... With the driving bands, it could be either, but I am going with a plated TBBC, since that would knock out a manufacturing process (plating).
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Meaning? ------------------------------- Meaning that the projectile that you posted a picture of isn't available in a 5.56mm/223 Remington load, nor as a .224 reloading component. (since the topic of this thread is the 5.56mm MK318 Mod 1 load ------------------------------- Doesn't matter. There are other bonded, and superior, hunting bullets available as components and factory stuff. The fine balance is accuracy vs performance. Ballistics gel is a good indicator, but should never supercede real world performance. My statement still stands. not really, provided you understand the scope of this thread. |
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Quoted: not really, provided you understand the scope of this thread. Quoted: Quoted: Meaning? Meaning that the projectile that you posted a picture of isn't available in a 5.56mm/223 Remington load, nor as a .224 reloading component. (since the topic of this thread is the 5.56mm MK318 Mod 1 load Doesn't matter. There are other bonded, and superior, hunting bullets available as components and factory stuff. The fine balance is accuracy vs performance. Ballistics gel is a good indicator, but should never supercede real world performance. My statement still stands. not really, provided you understand the scope of this thread. Yeah, I do. Please understand my first post, and contemplate what I stated. |
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Yeah, I do. Please understand my first post, and contemplate what I stated. Quoted:
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Meaning? Meaning that the projectile that you posted a picture of isn't available in a 5.56mm/223 Remington load, nor as a .224 reloading component. (since the topic of this thread is the 5.56mm MK318 Mod 1 load Doesn't matter. There are other bonded, and superior, hunting bullets available as components and factory stuff. The fine balance is accuracy vs performance. Ballistics gel is a good indicator, but should never supercede real world performance. My statement still stands. not really, provided you understand the scope of this thread. Yeah, I do. Please understand my first post, and contemplate what I stated. i'm sorry but i just dont see how your opinion on the bullets you like has any relevance to this thread and the new round the Marines are developing. |
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Quoted: i'm sorry but i just dont see how your opinion on the bullets you like has any relevance to this thread and the new round the Marines are developing. Quoted: Quoted: Quoted: Quoted: Meaning? Meaning that the projectile that you posted a picture of isn't available in a 5.56mm/223 Remington load, nor as a .224 reloading component. (since the topic of this thread is the 5.56mm MK318 Mod 1 load Doesn't matter. There are other bonded, and superior, hunting bullets available as components and factory stuff. The fine balance is accuracy vs performance. Ballistics gel is a good indicator, but should never supercede real world performance. My statement still stands. not really, provided you understand the scope of this thread. Yeah, I do. Please understand my first post, and contemplate what I stated. i'm sorry but i just dont see how your opinion on the bullets you like has any relevance to this thread and the new round the Marines are developing. I can see that. Because they are choosing a variant of an established hunting projectile to solve issues associated with subpar performance associated with projectiles that are either engineered to be accurate, penetrate helmets, or conform with certain rules.
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I can see that. Because they are choosing a variant of an established hunting projectile to solve issues associated with subpar performance associated with projectiles that are either engineered to be accurate, penetrate helmets, or conform with certain rules. Quoted:
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Meaning? Meaning that the projectile that you posted a picture of isn't available in a 5.56mm/223 Remington load, nor as a .224 reloading component. (since the topic of this thread is the 5.56mm MK318 Mod 1 load Doesn't matter. There are other bonded, and superior, hunting bullets available as components and factory stuff. The fine balance is accuracy vs performance. Ballistics gel is a good indicator, but should never supercede real world performance. My statement still stands. not really, provided you understand the scope of this thread. Yeah, I do. Please understand my first post, and contemplate what I stated. i'm sorry but i just dont see how your opinion on the bullets you like has any relevance to this thread and the new round the Marines are developing. I can see that. Because they are choosing a variant of an established hunting projectile to solve issues associated with subpar performance associated with projectiles that are either engineered to be accurate, penetrate helmets, or conform with certain rules. agreed......and i'm just glad to see the military moving in the right direction. anything is better than m855 for standard rifleman. |
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Quoted: Fully agreed.... With the driving bands, it could be either, but I am going with a plated TBBC, since that would knock out a manufacturing process (plating). Quoted: Quoted: And, since this is an ATK product, the bullet is probably a plated X bullet, or an untipped TBBC. Fully agreed.... With the driving bands, it could be either, but I am going with a plated TBBC, since that would knock out a manufacturing process (plating). i'm having deja vu here...when the Mk318 Mod 0 first came out, many people were saying that it was just an untipped TBBC bullet. turned out to be a whole new bullet with very different terminal ballistics. now were to the Mod 1 and people are saying the same thing again Mk318 Mod 0  Bonded Bear Claw  |
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Quoted: Quoted: Quoted: Quoted: And, since this is an ATK product, the bullet is probably a plated X bullet, or an untipped TBBC. Fully agreed.... With the driving bands, it could be either, but I am going with a plated TBBC, since that would knock out a manufacturing process (plating). i'm having deja vu here...when the Mk318 Mod 0 first came out, many people were saying that it was just an untipped TBBC bullet. turned out to be a whole new bullet with very different terminal ballistics. now were to the Mod 1 and people are saying the same thing again Mk318 Mod 0 http://sadefensejournal.com/wp/wp-content/uploads/2014/01/speer4.jpg Bonded Bear Claw http://www.natchezss.com/images/products/SP1725.jpg Slightly thinner frontal jacket to initiate partial fragmentation..... Voila! |
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i'm having deja vu here...when the Mk318 Mod 0 first came out, many people were saying that it was just an untipped TBBC bullet. turned out to be a whole new bullet with very different terminal ballistics. now were to the Mod 1 and people are saying the same thing again Mk318 Mod 0 http://sadefensejournal.com/wp/wp-content/uploads/2014/01/speer4.jpg Bonded Bear Claw http://www.natchezss.com/images/products/SP1725.jpg Slightly thinner frontal jacket to initiate partial fragmentation..... Voila! Quoted:
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And, since this is an ATK product, the bullet is probably a plated X bullet, or an untipped TBBC. Fully agreed.... With the driving bands, it could be either, but I am going with a plated TBBC, since that would knock out a manufacturing process (plating). i'm having deja vu here...when the Mk318 Mod 0 first came out, many people were saying that it was just an untipped TBBC bullet. turned out to be a whole new bullet with very different terminal ballistics. now were to the Mod 1 and people are saying the same thing again Mk318 Mod 0 http://sadefensejournal.com/wp/wp-content/uploads/2014/01/speer4.jpg Bonded Bear Claw http://www.natchezss.com/images/products/SP1725.jpg Slightly thinner frontal jacket to initiate partial fragmentation..... Voila! And non bonded core in the final production design. I believe there were test versions of Mk318Mod0 that did have bonded cores. |
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Although 318 Mod 1 is a contender; it probably will not be standardized The Marine Corps has been working with the Army to correct the problems with the M855A1 and will probably adopt that once the problems are resolved. What's the cost on M855A1 up to now? 
ETA: Not counting the costs of closing/upgrading ranges, weapons, etc. |
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How's that compare to the 262 and 318 round? I'm also asking about program cost. I've read that the Army has spent $100 million +/- on 855A1.......not to mention the lawsuit they just lost for stealing the IP.
ETA: Does $680 per 1k rounds seem f'in crazy to you too? |
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Army tends to be very parochial and if it was not invented by them they won't use it.
I don't know if that was the development cost; but I know there have been numerous exaggerations out there about the negatives of the round. It is not as bad as some make it out to be and seems to have shown very effective in usage. |
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Quoted: Army tends to be very parochial and if it was not invented by them they won't use it. I don't know if that was the development cost; but I know there have been numerous exaggerations out there about the negatives of the round. It is not as bad as some make it out to be and seems to have shown very effective in usage. well they didnt invent the M855A1 design...they stole it http://www.washingtontimes.com/news/2015/jan/14/liberty-ammunition-wins-156m-in-patent-theft-case-/ |
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well they didnt invent the M855A1 design...they stole it http://www.washingtontimes.com/news/2015/jan/14/liberty-ammunition-wins-156m-in-patent-theft-case-/ Quoted:
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Army tends to be very parochial and if it was not invented by them they won't use it. I don't know if that was the development cost; but I know there have been numerous exaggerations out there about the negatives of the round. It is not as bad as some make it out to be and seems to have shown very effective in usage. well they didnt invent the M855A1 design...they stole it http://www.washingtontimes.com/news/2015/jan/14/liberty-ammunition-wins-156m-in-patent-theft-case-/ Them and Caleb Crye should get together. |
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Them and Caleb Crye should get together. Quoted:
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Army tends to be very parochial and if it was not invented by them they won't use it. I don't know if that was the development cost; but I know there have been numerous exaggerations out there about the negatives of the round. It is not as bad as some make it out to be and seems to have shown very effective in usage. well they didnt invent the M855A1 design...they stole it http://www.washingtontimes.com/news/2015/jan/14/liberty-ammunition-wins-156m-in-patent-theft-case-/ Them and Caleb Crye should get together. Zia, the last thread on that, that I commented on, turned into a huge shitfest. As for this round, I am sure it is it's own animal. But, when I first saw the thread, I thought of something along the lines of a TSX. If that indeed is the case, it should be pretty cool. |
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I am pretty sure that the Mk318 Mod 1 has replaced the lead core with a sintered (powdered) copper rather than solid copper. so it will fragment. Specific gravity of lead alloy is around 10.0 and copper alloy 7.0 so it has to be longer. The Mk318 is great ammo. If you look at the inside profile of the jacket you will see that the jacket is designed to break off the solid copper base. The jacket is intentionally weak where it meets the base, no additional thickness there at all. Ive shot coyotes with it and it fragments right now! And the base weighs over 20 grains, twice the steel tip in M855 ammo. Good stuff.
Note photo of M855A1 gelatin shot! |
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No, but it would prevent copper fouling. Quoted:
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Does the nickel plating increase wear on the bore? It seems a silly thing to nickel plate the bullet just to “color code” it. No, but it would prevent copper fouling. I agree it would prevent copper fouling, but how about nickel fouling? I know that over a century ago, the cupro-nickel jackets would cause fouling, which was difficult to remove, and harmed accuracy. (I know this by reading, not actual experience  ).
I also know that Winchester uses nickel plating on some of their jacketed Silvertip handgun bullets, (aluminum on others). When they say nickel, I assume that they are referring to a nickel alloy. Maybe that is what I get for assuming, though. |
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i'm having deja vu here...when the Mk318 Mod 0 first came out, many people were saying that it was just an untipped TBBC bullet. turned out to be a whole new bullet . . . MK318 Mod 0 (Federal T556TNB1) 
One version of MK318 Mod 0 that is now available to the general public is being sold as Federal "white box" T556TNB1. The SOST projectile loaded in the MK318 Mod 0 cartridge has a nominal weight of 62 grains and a nominal length of 0.87”. It is constructed with a copper base and a small, non-bonded lead core in the ogive section of the bullet. Due to this higher copper to lead ratio, the MK318 Mod 0 projectile is longer than a traditional copper jacketed/lead core projectile of the same weight, but is still slightly shorter than an M855 projectile. 
While it is often stated that the SOST projectile used in MK318 Mod 0 is similar to the Federal Trophy Bonded Bear Claw, the form of the SOST projectile more closely resembles that of Federal’s Trophy Bonded Tip projectile (without the tip of course.) As previously mentioned, the MK318 projectile does not have a bonded core. 
The loaded MK318 Mod 0 cartridge has a nominal OAL of 2.20". The projectile does not have a cannelure per se, but the case mouth is crimped into the top relief band. The cartridge is sealed at the case mouth, however not with the asphalt sealant typically found on military ammunition. The primers are sealed and crimped. The casehead is stamped "FC 10". The cartridge is charged with ball powder. 
A typical copper jacketed/lead core FMJ bullet will have a specific gravity of approximately 10.2. Due to its higher copper to lead ratio construction, the MK318 Mod 0 projectile has a lower specific gravity. When fired from typical AR-15 barrel lengths with a 1:9” twist rate, MK318 Mod 0 will have a gyroscopic stability factor of approximately 1.3. 
When fired from typical length barrels with a 1:7" twist rate, MK318 Mod O will have a gyroscopic stability factor of approximately 2.2. 
MK318 Mod 0 Chronograph Data Chronographing of the Mk318 Mod 0 ammunition was conducted using an Oehler 35-P chronograph with “proof screen” technology. All velocities listed below are muzzle velocities as calculated from the instrumental velocities using Oehler’s Ballistic Explorer software program. All strings of fire consisted of 10 rounds each. 
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: 75 degrees F. Humidity: 47%. Barometric pressure: 29.97 inches of Hg Elevation: 950 feet above sea level Two different barrel lengths were used in obtaining velocity data; a 14.5” Colt M4A1 barrel and a 20” Colt M16A2 barrel. Both barrels have NATO chambers, are chrome lined and have 1:7” twist rates. Both barrels have low round-counts on them. M4A1 barrel. 
M16A2 barrel. 
For comparison, the MK318 Mod 0 ammunition was fired in sequence with two different brands of 62 grain M855 ammunition. The firing order for both barrels was as follows: 1.A 10-shot string of Winchester Ranger M855 2.A 10-shot string of MK318 Mod 0 3.A 10-shot string of IMI M855 Finally, the data: 
The Crane Warfare Centers' publication, “U.S. Navy Small Arms Ammunition Advancements” reported that MK318 was “optimized” for the MK 16 with a 14 inch barrel and claimed it has a velocity of 2925 fps at 15 feet from the muzzle (presumably from said 14 inch barrel.) The lot of Federal T556TNB1 (MK318 Mod 0) that I chronographed from the Colt 14.5” M4A1 barrel would have a velocity of approximately 2889 fps at 15 feet from the muzzle (at standard atmospheric conditions.) Accuracy Evaluation of MK318 Mod 0 An accuracy (technically, precision) evaluation of the MK318 Mod 0 ammunition was performed 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 each barrel 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 barrels used in the evaluation were free-floated. The free-float handguards of the rifles rested in a Sinclair Windage Benchrest, while the stock of the rifles 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 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. 
In order to establish a working baseline for the intrinsic accuracy of the 62 grain SOST projectile itself, when fired from a semi-automatic AR-15, I worked-up a SAAMI pressure hand-load with pulled MK318 bullets and fired a 10-shot group of that load from a Krieger barreled AR-15 from a distance of 100 yards. The Krieger barrel has a 1:7.7” twist rate. 
Prior to firing the 62 grain SOST hand-load, I fired a 10-shot control group consisting of hand-loaded 62 grain Berger hollow points. The extreme spread for the control group measured 0.66”. 
The extreme spread of the 10-shot group of the 62 grain SOST hand-load measured 1.9”. 
Since MK318 Mod 0 is intended for use as a combat round, I used AR-15s with chrome-lined, NATO chambered barrels for this accuracy evaluation, as it most likely that these are the types of barrels that this ammunition will most commonly be fired from. It is sometimes possible to obtain slightly better accuracy from mil-spec/NATO pressure loads by firing them from an AR-15 that has a stainless steel match-grade barrel with a hybrid chamber such as the Noveske NMmod0 chamber or the Wylde chamber for examples; but you're not going to make a silk purse out of a sow’s ear. As previously mentioned, it is reported that MK318 was “optimized” for a 14 inch barrel, so it seemed only fitting to evaluate MK318 from a similar length barrel. The first test vehicle used in this accuracy evaluation was a 14.5” Colt M4A1 barrel. The barrel was free-floated with a Daniel Defense Omega rail. (I was not able to use the mirage-shade with this barrel, due to the original standard front sight base on it.) A previous accuracy evaluation of this M4A1 barrel demonstrated that this barrel is capable of excellent accuracy for a chrome-lined, NATO chambered barrel. That evaluation can be viewed here: The Colt M4A1 SOCOM Barrel 
A control group fired from the M4A1 barrel using hand-loaded 62 grain Berger hollow-point projectiles had an extreme spread of 1.13”. 
Three 10-shot groups of the MK318 were fired from the Colt M4A1 barrel from the previously described bench-rest set-up. The extreme spreads of those groups measured: 2.91” 3.22” 2.70” for a 10-shot group average extreme spread of 2.94”. 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 of this composite group was 1.02”. (For those of you not familiar with the mean radius, I've posted an explanation of it in the third post of this thread.) The smallest 10-shot group of MK318 fired from the Colt M4A1 barrel is shown below. 
The next test vehicle was a 16” Colt HBAR with a 1:9” twist. This is the same barrel found on the Colt 6721 Tactical Carbine. This barrel is one of the most accurate “out of the box” chrome-lined, NATO chambered barrels that I’ve evaluated. The barrel was free-floated with a LaRue Tactical handguard. 
A 10-shot group from this barrel fired using hand-loaded Sierra 52 grain MatchKings had an extreme spread of 0.98”. 
Three 10-shot groups of the MK318 fired from the Colt 6721 barrel produced the following extreme spreads: 2.98” 2.85” 2.89” for a 10-shot group average extreme spread of 2.91”. These three groups were also over-layed on each other to produce a 30-shot composite group with a mean radius of 0.82”. The smallest 10-shot group of MK318 fired from the Colt 6721 barrel . . . 
The third barrel used to evaluate the accuracy of MK318 was a 20” Colt HBAR with a 1:7” twist, chrome-lining and a NATO chamber. The barrel is free-floated with a PRI handguard. 
A 10-shot group from this barrel fired using hand-loaded 55 grain Sierra BlitzKings had an extreme spread of 1.18”. 
Three 10-shot groups of the MK318 fired from the 20” HBAR had extreme spreads of: 2.70” 2.49” 3.24” for a 10-shot group average extreme spread of 2.81”. As before, the three 10-shot groups were over-layed on each other to form a 30-shot composite group that produced a mean radius of 0.91”. The smallest 10-shot group of MK318 fired from the 20” HBAR . . . 
A summary of the results from this evaluation are shown below. 
Lastly, for the Internet Commandos in our viewing audience, here’s a pic of a sub-MOA group of the MK318 fired from the 16” Colt HBAR from 100 yards; a cherry-picked 3-shot group that is. 
AB49 
MK318 Mod 0 is also available to the general public in a “brown box” version. This version is labeled with the Department of Defense Identification Code of AB49. - V e l o c i t y - C o m p a r i s o n - Following the same chronographing procedures outlined in the first post of this thread, I compared the velocities of T556TNB1 “white box” MK318, to that of AB49 “brown box” MK318. The two versions were fired “back to back” from three different barrel lengths: > 14.5” Colt M4A1 (the same barrel used for the first post) > 16” Colt light-weight barrel, 6520 > 20” Colt M16A2 (a different barrel than the one used for the first post). All three barrels are chrome-lined and have NATO chambers and 1:7” twist rates. The velocities listed below are muzzle velocities as calculated from the instrumental velocities using Oehler’s Ballistic Explorer. Atmospheric conditions. Temperature: 72 degrees F Humidity: 68.1% Barometric pressure: 30.02 inches of Hg Elevation: 950 feet above sea level 
- A c c u r a c y - C o m p a r i s o n - Using the same 20” Colt HBAR, described in the original accuracy evaluation in this thread, as the test vehicle, I performed an accuracy evaluation of the AB49 “brown box” MK318 ammunition. The evaluation was conducted from a bench-rest at 100 yards in the same manner as previously described.
Prior to firing the AB49 ammunition, a 10-shot control group of hand-loaded, match-grade 55 grain Sierra BlitzKings was fired from 100 yards. That group had an extreme spread of 1.00”. 
Three 10-shot groups of the AB49 fired from 100 yards had extreme spreads of: 3.26” 3.42” 3.31” for a 10-shot group average extreme spread of 3.33”. The mean radius for the 30-shot composite group was 0.98”. The accuracy results are summarized and compared to those of T556TNB1 below. 
The smallest 10-shot group of AB49. 
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I agree it would prevent copper fouling, but how about nickel fouling? I know that over a century ago, the cupro-nickel jackets would cause fouling, which was difficult to remove, and harmed accuracy. (I know this by reading, not actual experience ).
I also know that Winchester uses nickel plating on some of their jacketed Silvertip handgun bullets, (aluminum on others). When they say nickel, I assume that they are referring to a nickel alloy. Maybe that is what I get for assuming, though. Quoted:
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Does the nickel plating increase wear on the bore? It seems a silly thing to nickel plate the bullet just to “color code” it. No, but it would prevent copper fouling. I agree it would prevent copper fouling, but how about nickel fouling? I know that over a century ago, the cupro-nickel jackets would cause fouling, which was difficult to remove, and harmed accuracy. (I know this by reading, not actual experience ).
I also know that Winchester uses nickel plating on some of their jacketed Silvertip handgun bullets, (aluminum on others). When they say nickel, I assume that they are referring to a nickel alloy. Maybe that is what I get for assuming, though. Lazzeroni loaded NP3 coated X bullets to prevent copper fouling. |
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I am pretty sure that the Mk318 Mod 1 has replaced the lead core with a sintered (powdered) copper rather than solid copper. so it will fragment. Specific gravity of lead alloy is around 10.0 and copper alloy 7.0 so it has to be longer. The Mk318 is great ammo. If you look at the inside profile of the jacket you will see that the jacket is designed to break off the solid copper base. The jacket is intentionally weak where it meets the base, no additional thickness there at all. Ive shot coyotes with it and it fragments right now! And the base weighs over 20 grains, twice the steel tip in M855 ammo. Good stuff. Note photo of M855A1 gelatin shot! Please let us know where this info came from. Thank you. |
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Sal said in the article that,
"We found that we could replace the lead with copper, stretching the jacket around ever so slightly so it allowed us to crimp the nose even more." Sounds like it is a two part bullet (swaged or imact extruded jacket/base and core) not a one part like a Barnes X. M855A1 also uses a sintered core material. A 62 grain Barnes X is 0.942 inches long, quite a bit more than the Mk318 bullet (0.87) The new bullet looks no different in length than the old one. Whatever the core is made of it must have something heavier than copper added to it? |
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Quoted: Sal said in the article that, "We found that we could replace the lead with copper, stretching the jacket around ever so slightly so it allowed us to crimp the nose even more." Sounds like it is a two part bullet (swaged or imact extruded jacket/base and core) not a one part like a Barnes X. M855A1 also uses a sintered core material. A 62 grain Barnes X is 0.942 inches long, quite a bit more than the Mk318 bullet (0.87) The new bullet looks no different in length than the old one. Whatever the core is made of it must have something heavier than copper added to it? are you sure about the M855A1 using a sintered core material?  |
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Yes, you can just barely see the density difference in the cross section.
Other photos on line show it a little bit better. The wound profile of a monometal is very different from a fragmenting MK318. I would be surprised the USMC would still call a monometal a Mk318? |
[ARCHIVED THREAD] - USMC Gets the Silver Bullet (Page 1 of 2)
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