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.

Attached File



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.


Attached File






....

This round doesn't rely on fragmentation as much as expansion.



Also, water jug tests don't tell you anything except how well the round does vs water jugs.



 

as i've said before ballistics jel is 90% water so firing into water jugs will show you what the round would do. You dont have the wound channel to look at but the bullet does the same thing.

This bullet dosent expand the jacket is very thin and fragments.

Looks like there is now a third version of MK318 packaging.

MK318 in NEW BOX

IIRC, the BVAC are another companies' loads using pulled Mk318 bullets, not Federal Mk318 as a complete cartridge.

I just bought 13 boxes of this for $9 a box at a gun show today. Does it perform as well or close enough to the Federal stuff or does anyone know? I noticed they are crimped with a FCD into the top grease ring instead of roll crimped over the top drive band and the bullets can be slightly turned inside of the casing on a few of the bullets. I can't tell and haven't pulled one yet, but I would almost bet they don't have a grease seal on them.

Also, they don't seem to have crimped primers either.

What fo you mean that it could be fatigued?  That round uses new brass.

I just pulled one of the BVAC rounds that i found to have a loose projectile about halfway out of the casing with a kinetic puller. These are not sealed, in fact I pushed it back in place with my fingers and re-crimped it with my FCD and now it no longer spins freely. I'm gonna go through and double check them all and re-crimp what needs it and never buy ammo from them again. I sent an email to them asking if they are loaded to give the same velocity as the real stuff but still waiting on the answer.

Im trying to figure out why they are cheaper.  New brass, same bullet, the only thing left is the powder.  They say that it 5.56 but Im not sure where they learned how to load them.  

Ill either be buying another 1000 rounds of Federal Mk318, ir trying the BVAC.  I havent made that decision yet.
Facts as of now: New brass, new bullets.  This is confirmed by BVAC.

I got a response back from BVAC but all it said was they are loaded to exact specifications as the real stuff and the loose projectile is ok as long as bullet push is tight.

If it were loaded to exact (mil)-specifications it would be properly crimped, sealed and use a hard cup primer.  I could see them saying it was loaded to match mil-spec performance.  I was about to pull the trigger on some of this.  I've always had good luck with HSM so I figured BVAC should be of the same quality.

Im confused, is the bvac version not a sealed primer?

Not that I can tell.

Anyone have any accuracy tests of the BVAC?

And preferably not bought from a gunshow, that guy could have loaded those himself

You think someone is gonna reload a Mk318 round and try and pass it off as BVAC instead of Federal? Small gains for the trouble I think.

I tried some of the BVAC mk318 loads a couple weeks ago in my 16" LMT MRP which has a 1:7 twist and i was getting around 5" groups at 100 yards.  I shot several other BVAC loads and found my rifle just didn't like their stuff but that is not to say you will see the same results.  I bought some pulled mk318 bullets from the EE and have been able to get less than 2" groups so far.

Ok, I shot my gun show purchased BVAC Mk318 yesterday and had pretty good results. It isn't match quality by any means, but it held under 2 MOA for me pretty well. It also blew the back out of a 2x4 quite nicely too. This was bought at a gun show from a reputable local dealer so I do not expect it to be counterfeit but I guess anything can happen iIf it is counterfeit then he did a good job at it.

My complaint about it is that the primers are not crimped or sealed and the bullets are lacking the grease seal. Other than that performance was as expected.

I just got my bvac mk318 and i noticed this too. Primers dont appear to have sealant, neither do the bullets.  My federal does though.

If they were using the MK318 in the M16's and M4's but you were using MK262, what rifle were you using?

MK12 Mod 1

I must disagree. I was having some severe accuracy problems with some of my reloads, and I found that the bullet was moving FORWARD when the cartridge was chambered, and came to a stop, even though the bullet was not seated loosely and passed the push test against a bench. A couple thou. polished off the expander ball cured the problem. A loose bullet in the case is a no-no.  So, measure a BVAC round with a loose bullet for OAL, load it in your mag with a round chambered, fire the weapon, gently extract the round that you measured, and see how much further forward the bullet has moved. Mine moved as much as 14 thou. forward, and the bullet was tight and could not be moved by hand. Accuracy sucked.  I would run all the Bvac rounds through a crimp die and use them up in practice, and that would be that for BVAC.

I just ran them through my fcd and shot a box of em and they were fine.

Superior report, Sir

Gents,

I took some handloaded ammo with pulled Mk318s on a feral pig hunt just to see how they'd perform.  Only was able to take one pig, a 250 pounder, from fairly short range.  Two bullets were recovered from the body cavity.  They had both completely shed the nose (the copper and lead) with just the copper shank being left.  Remarkably, the remaining weight on the two is only one tenth of a grain different.  Very consistent.  I was kind of surprised, being barrier penetration rounds, that they stopped within the pig.  I'd post a photo of the recovered bullets, but can seem to find a way to upload one.


Matt

www.tinypic.com

Distance and barrel length?
Impact point, angle, structures penetrated and distance traveled in said pig?

So in your opinion which round is better?

MK 318 or M855

MK 318

Molon , Thanks !!! That is great information.

Posted Via AR15.Com Mobile

got a box of T556TNB1 this week for testing



Steyr AUG-A1

20" barrel, 1/9 twist

1.5x optic

Talk about thread resurrection.

I haven't seen any of this ammo for sale since Sandy Hook. Where did you find your box for testing?

someone at pistol-forums sent it to me.  psa just started selling it again for $18/20



 

It's out there. PSA has it.

Interesting article with one of the individuals involved with the development of MK318:

SADJ MK318 article

Already posted: http://www.ar15.com/forums/t_3_16/667677_USMC_Gets_the_Silver_Bullet.html

more thread resurrection;

i had about the same results you did at 50 and 100 yds with my SCAR 16 and an aimpoint.

Fantastic report on what appears to be crappy ammo.

it seems to meet the same accuracy spec as M193 (<=1" mean radius @100 yds).  its terminal ballistics though is a huge improvement over M193/M855.  i'm really curious what the changes in the Mod 1 version will do



 

crappy ammo? i recall reading the Marines that used it in afganastan were happy with its terminal effects. it'd take a pallet of this over any fmj.

 resurrecting this thread since its relevant to my interests and others here. i was zero'ing this mk318 on paper one day at 50 yds and poked around the dirt behind my box and found the slug. i had some hornady 55gr GMX with me too so i shot one into the soft dirt (soft for southern AZ, so it wasnt just solid rock!).    

50 yards with a 2 MOA aimpoint...4 inch black circles, shooting off of a bipod...


GMX mushroomed on the left side, mk318 on the right

THX OP!!!


so some guy called po boy special, has a youtube channel, maybe has an acct here, maybe someone already mentioned this between the OP and here, but that fellow tested like a copule dozen types of ammo from his 7.5" AR.  There is youtube playlist on his channel and a spread sheet you can download from his site.  Of all the rounds, 14 fragged &/or expanded, 11 penetrated to 12" or greater.  

of all of them that had an expanded slug left, the mk318 expanded to .461" and partially fragged.  penetration was a little much, 21.5".  Energy was a respectable 700 ft-lbs at the muzzle, 2255 fps.    Thoug the penetration may be higher than is ideal for many scenarios, this had the best all around performance, IMO.

Retained weight was 46 grains

here is vid for that test:
https://www.youtube.com/watch?v=FNekOq9CBQA&index=21&list=PLW31XX5XBJOrDU1GQhsKrFBUsJjo5RWPd

Energy transfer is not a wounding mechanism for small arms fire.





WHAT'S WRONG WITH THE WOUND BALLISTICS LITERATURE, AND WHY

by M.L. Fackler, M.D.
Letterman Army Institute of Research
Division of Military Trauma Research
Presidio of San Francisco, California 94219
Institute Report No. 239




The “Shock Wave” Myth

By Dr. Martin Fackler

Wound Ballistics Review, Winter 1991 and the Journal of Trauma, (29[10]: 1455, 1989).





Ballistic Injury

By Dr. Martin Fackler

Annals of Emergency Medicine, December 1986




Bullet Penetration

By Duncan MacPherson





Handgun Wounding Factors and Effectiveness

By Special Agent Urey W. Patrick
Firearms Training Unit
FBI Academy

Just bought a thousand pulled MK 318 Mod 0 projectiles. This thread is relative to my interests!

that round from the video travelling at 2250 is interesting in that the pedals peeled back and stayed on the base. i'm guessing that at higher velocity is when the pedals sheer off. now where is that theshold?

I have had good results with 25.0 gr of cfe 223 and #41 primers

i have had better luck with milder loads

A couple of the goals for the new projectile are that is to be "barrier blind" and "limits fragmentation."  Since they supposedly (I haven't seen any actual cross sections yet) will "replace the lead with copper" in the new projectile, it sounds like it will be a 62 grain monolithic hollow-point; but who knows.  One would expect terminal performance to be similar to the 62 grain TSX.



...