Hi,

I bought 1640 rounds of MK 318 MOD 1 from BFGC back in July of 2020 during the Covid panic buying frenzy.  I didn't know much about it and mainly bought it because nothing else was available at the time.  I packed it away on a shelf and forgot about it until recently.  I've been trying to research it to learn how it compares as I am looking for a good SD round for my ARs, but couldn't find a lot out there.  So, I have a few questions for those that might have experience with this round:

- Is this a good performing round?  Is it on par with something like Federal XM556SBCT3 (also from BFGC) for defensive purposes?  Can this be used effectively in an 11.5?

- Someone mentioned on an older archived ARF thread that this round has lead-free primers and thus has a shelf life of about ~10 years.  I could find no mention of this anywhere else on the internet but wanted to check and see if anyone else has heard this.  Doesn't seem smart for military ammo to have such a short shelf-life.

- Given that this is no longer produced to my knowledge, should I use it or just put it back on the shelf?

Thanks in advance for any input.

Hey neighbor,
See if this helps:
MK318

Thanks!  Spent time searching last night and somehow missed this.  Very much appreciated.

Generally, it is an exceptional self defense round.  It is highly barrier blind, expands, and has higher velocity than comparable 223 rounds.  


Its a good choice.  Keep in mind, it tends to penetrate really well...so know your backstop and beyond.

OP, you’ll be off better ignoring anything you see posted in this thread and basing your decisions for your choice of self-defense loads on the findings of actual experts in the field of terminal ballistics.  This sub-forum used to be an excellent source of information.  Zhukov and I have put in an immeasurable number of hours posting factual information in this sub-fourm, but it has become infested with people who don’t know what they’re talking about trying to pretend that they do and posting false information.

As I posted in the thread that lapster linked to, MK318 Mod 1 does not contain any lead to expand or fragment.  It’s basically just two separate chunks of copper and the round just fractures at the seam of those two pieces instead of expanding and it badly over-penetrates.  The IWBA and FBI penetration specification calls for a penetration of 12”-18” in properly prepared and validated bare 10% organic ballistic gelatin.  I’ve seen Mk318 Mod 1 penetrate to 30”.  It’s a piss poor choice for a civilian self-defense load compared to loads that actual experts in the field of terminal ballistics recommend for self-defense.

Mod 0



Mod 1


…

Molon - thanks for the post.  Good info.

As I mentioned, it was all I could find at the time and I knew very little about it so it was a gamble.  I guess I'll start shopping for something better suited for HD.

Not that I'm an SME by any means, but I tested some MK318 Mod1 here a few weeks ago. Accuracy wasn't as good as M855A1 (which isn't great either), and against our gel, it had crazy amounts of penetration as Molon mentions. It dumps the front half and its guts and then the bottom half just keeps chucking along.  I wouldn't use it for SD/PP.

That's pretty good performance for live tissue....


318 is specifically designed for human threats behind barriers.  It does this very well.  Its also lead free and can be used on ranges that don't allow steel projectiles.  


Its supposed to deform or shed the front core and the mushroom petals may break off as well, depending on what it hits.  This is a design feature to ensure straight line penetration through barriers like windshield glass.  

It will penetrate beyond that FBI recommended max, but that's not really much of a problem.  


318 is an awesome general purpose duty round.  Its not a precision rifle round...but it is more than precise enough for guns with red dots.  Anyone running it as a general purpose self defense round has made a solid choice.  Several Federal LE teams run it and have multiple real world shootings on vehicles where it performed exactly as designed.  

Is this Mod 0 or Mod 1? It's Mod 1 that's the insane penetrator

Picked up thousands of the bullets for cheap when they were being dumped.  At full NATO pressure accuracy is OK.  Drop it 100 FPS, and it tightens up and groups halved to pretty great accuracy.  

I personally consider MK18 Mod1 the best general purpose bullet you can get.  As to terminal, in theory the front core is "sintered" and designed to basically explode like a varmint round, while the back is harder and designed to penetrate.  Giving you best of both worlds, and being "barrier blind" while also effective on soft targets.  I would think it's terminal performance beats M855A1.  It's accurate, if you are a reloader and it doesn't do weird things that require new mags.

As Molon says, it will over penetrate - so if your setting is one where that is a concern - there you go.  If you're in the woods looking to night hunt Coyote's and Hogs out of the same magazine, there you go.

MOD 1 is an improvement.  The copper slug up front is dead soft.  It is built to deform and expand, albeit not as much as lead would.  On Gel, the front slug often doesn't deform.   It can definitely penetrate...and it will shear the petals off on barriers...but the net weight on the remaining slug is usually insufficient to be a huge penetration hazard like you see with actual black tip or similar.  

Yes, MOD 1 will penetrate more than something like 55 Gr ball...but penetration is a necessary evil to ensure you get to the threat who might be behind some form of barrier.  

The gist of barrier ammo is that it must first reach the threat...penetrate...then everything else can happen.  So, they build it to penetrate...and it does.  

Its admittedly a tradeoff.  There are valid uses for highly fragile bullets.  If you KNEW up front that you were going to shoot a threat 25 yards away who was standing upright wearing only a T Shirt...Hornady V Max would be an outstanding choice.  It would be devastating, safe, and effective.  Add in some windshield glass....and you have problems.  


Its all give and take.

Mod 1 also solved some of the coppering problems the Mod 0 had.

AAC is supposed to be coming out with a Mk318 clone. I assume of Mod 0

I personally don't feel that's the case. M855A1 is fragmenting out as low as 7.5" barrels, and typically provides 2 distinct wound channels out to FBI penetration depths.

Most people don’t like to leak and most hit from a rifle prove effective.

But my personal take is most hits cause psychological and not physiological stops, and the majority of difference in effect between various like rounds is just for the few cases of people where only a physiological stop will work

FBI T3 is already a basic clone of 318...not exactly as The Marine Corps adjusted the bullet profile to achieve relative trajectory match to the ACOG reticle...but the bullet tech is almost identical.  

Its all derived from the Trophy Bonded Bear Claw hunting bullet.  If you look at a cutaway of a TBBC, FBIT3, and 318 MOD1...and 2....its all very very similar.  The MC bullet is the most tweaked and optimized for ballistics, reduced fouling (relief grooves), and is lead free.