Hi Guys,

I'm new to the .50 BMG hobby and have some questions about a particular round - next generation MK263 AP "match" rounds. I watched a video on Youtube and I'm really impressed with their performance - these rounds seemed to perform slightly better than SLAP rounds and blow old M2 AP away. It seems that they will penetrate about 1.5 inches of steel plate from what i have seen.

As for the rounds, I cannot find anyone selling "live" or fully assembled rounds. But, a vendor is selling the new projectiles. This is the information they posted about them:



In researching, that description is from a Canadian company that I believe manufactures these rounds (General Dynamics) and they are listed as 750 grain projectiles. So, my questions would be:

1. Does anyone have any suggestions on load data for trying to replicate a MK263 load using these projectiles? I see that Hornady A-MAX projectiles are also 750 grains. So, maybe I can start with load data for that projectile and adjust from there?

2. Has anyone seen MK263 AP rounds in action? Any input on the accuracy and AP capabilities these rounds offer?

Any input would be appreciated!

I asked this question myself several months ago and nobody really had any more information that what you have seen.  I know exactly the vendor you are referring to and have considered picking up 100 or so of the projectiles myself.  Going back when I made that post there was another seller on GB than had loaded MK263 rounds at $7 per round.  I did not buy any as I was not convinced he was not loading them himself although he claimed them to be factory LC.  The ones he had for sale had legit looking black painted tips whereas the projectiles for sale have never been painted or had the black paint removed.  These are interesting projos for sure and appear to me they would be close to MK211 in penetration if loaded correctly.  Have you purchased any of the projos?  Update:   Holy smokes they have raised the price a lot!  $1.75 each.

Thanks for the input! I guess the only way to find out is by doing. So, i may as well buy some projectiles and start my testing. Yes that seller (Spectre Supply) said to me he is "by far the cheapest in the country" for those projectiles. What did he used to have them listed for? It sounds like he isn't willing to budge on the projectile price, not even for a bulk purchase.

And as for the painted black tips, I know that manufacturers will only paint the tips AFTER the round is loaded. So, it makes sense that these raw projectiles aren't painted - he is listing them as NEW. So, they wouldn't have paint on them unless they are pulldown projectiles.

And if MK211 is the Raufoss ammo that was shot in the comparison video, it didn't do well at all - it just barely penetrated the first 1 inch plate. The MK263 cut right through the first 1 inch plate and made it through about half of the second 1 inch plate. Here is the video:

https://www.youtube.com/watch?v=QGLLTjYRNag

He had them listed for $1.50 previously.  Looks like he sold 3 batches of 100 in the last 30 days which is not a lot but he must have concluded the price was too low.  There was at least one other seller that had them but I don't see them at the moment.  I don't have loading equipment at this time so I may just pick up a hundred or so for later use.  Thank you for posting the link to the vid.  I searched before but could not find anything about this ammo.

No problem!

I take back what I said earlier. If you look at the other videos posted by the same guy, the SLAP rounds do better than the MK263 - it will penetrate 1.5 inch titanium plating. MK263 wouldn't even penetrate 1 inch of titanium. And per the commenters on the original video, that M2 AP round he shot was really just a ball round with a mild steel core.

Either way, I still think these NEW MK263 rounds are the most economical. People are charging $2 per round for old surplus M2 AP projectiles nowadays. SLAP rounds are over $60 per round loaded. Or, $30 per projectile. And, you can't use a standard muzzle brake with SLAP. I'll see how much this "match grade" accuracy turns out to be for MK263.

My .50 BMG press kit is on back order. So, I have some time to acquire components while I wait!

I still wonder if this projectile will penetrate better than US M8 API or M20.   At 750 grains with a much larger hardened core I could see it performing better but then again you will lose velocity going to the heavier projo.

I have 1 or 2 of the Athena rounds around here someplace from when I was at Barrett.  They were very accurate.
Probably the most accurate production rounds I ever shot were Winchester solid copper 750 grain open tip rounds. The tip was .125" in diameter. .750" deep.  Tried snagging one of the rounds to dissect but the Winchester rep kept tight control of the loaded rounds and fired casings.  Wanted to see the boat tail design.
I fired them at 2000 meters at a scrapped humvee and a 55 gallon drum.
This was at Ft Drum when the Army decided on the XM107.

The ones I fired had the WCC head stamp. It was early in the XM107 adoption, so the WCC was probably the first iteration of the round.

I'll have to test them out and hopefully compare them to M2 AP when I develop some loads. Supposedly the dual channel/cannalure on the MK263 projectile is supposed to increase velocity. So, I would imagine it's still on par with M2 AP velocity-wise even though it's heavier. I'm also interested to find out about the "inert chemical filler" in the tip of these projectiles. Maybe they just used it cause it was cheaper than lead?

Well it looks like American Marksman has loaded a batch of MK263 and has them for sale on their website at $5 per round.  I would jump on it but you have to buy 150 at a time so it's $750 plus shipping.  That's a bit too high for me but I would gladly try maybe 30-50 rounds at $5.

How does one know its a real M263 projectile?  I'm *GUESSING* that being an accurate projectile and the mention of a chemical filler at the tip, its an OTM type construction that they then put a filler in the little hole?  That would distinguish it from old AP or M33.

Mk263 is 750 gr.
AP M2 is 705-710 gr
Ball M33 is 650-665 gr.

AP M2 has the unique jacket end foldover on the base of the core
Ball M33 has a lead base plug

AP M2 and Mk263 have smooth crimp cannelures and some of the Mk263 have an extra cannelure on the bullet below the crimp cannelure (can't see it loaded to the case) where the M2 AP only has the single smooth crimp cannelure.  If it's the sniper grade Mk263 there are NO cannelures at all on the bullet as the case mouth isn't crimped into the bullet.  MG version of the Mk263 has at least one smooth crimp cannelure or the two smooth cannelures (depending on production source, LC or IVI)
Ball M33 has a knurled cannelure.

AP M2 and Mk263 have black tips, Ball doesn't have any color code.

If you cut the bullets open, the AP M2 has a lead nose filler, the Mk263 has an inert powder nose filler.  The Ball M33 has an inert nose powder filler.

Ball M33 has a mild steel core, AP M2 and Mk263 have hardened steel cores.

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I just got this today. For $637.50, I hope it's the real deal.

If it shoots as good as Hornady Amax, I may need to buy 2 more ammo cans before it's sold out.

Website says AP but can does not and no black tips?

The ups guy dropped some of this off at my door yesterday.

I pulled a bullet and cut it apart since the ID paint was missing on mine as well.  The one I pulled weighed the right amount and definitely had a hardened steel core.  

I haven't shot it yet so I can't say on the accuracy, but the large variance in cartridge OAL isn't going to help.

Edit: the jacket is also undercut in the bearing surface area,, I'm 100% sure what I got is M263

And as for the painted black tips, I know that manufacturers will only paint the tips AFTER the round is loaded. So, it makes sense that these raw projectiles aren't painted - he is listing them as NEW. So, they wouldn't have paint on them unless they are pulldown projectiles

Correct! The ONLY time you'll get paint on your projectiles if it's military loaded ammunition that was "pulled down" for parts. These are NEW projectiles American Marksmen are loading into new ammunition they are manufacturing from what I gather.

For the guys that scored some of these rounds, please be sure to post range reports once you get a chance to shoot some MK263 rounds off. I'm excited to learn about their accuracy and penetration power. I gather they can penetrate 1.5 inches of mild steel in watching videos online. And for those that disassembled a round, are these the double cannalure projectiles? Were they crimped? What weight did you read on the powder charge?

I shot some of the MK263 rounds from American Marksman. Results were the following:

Accuracy was similar to surplus ammo.
Felt recoil was similar to surplus ammo.
I noticed that the OAL was not consistant.

We shot 15 rounds. One of the fifteen rounds did not function. The primer was pressed in to far. I would have thought that QC would have caught that.

My overall opinion of the ammo is meh. I'm glad that it is AP, but that's about it. At $4.25 per round, I kind of expected more.

From what we gather, this stuff is NOT remanufactured. No pull marks and no tip painting leads us to believe American Marksman is just buying the NEW MK263 projectiles that are for sale out there and loading it into new manufacture ammunition. But, it seems QC is lacking from what @crazyz is reporting. Unfortunate as I think this round has great potential if loaded properly.

I'll see what I can do with hand loads using new MK263 projectiles. I just got my backordered Lee 50 BMG press kit in the mail the other day. I still gotta gather all the components though.

Did anyone that received the American Marksman rounds get a chance to pull a projectile and weigh the powder charge they are using?

Mk263 did great against steel though.  Much more practical than Ti as you will probably never have to shoot at an A10 bathtub, and if you do, not much else matters as you're screwed

Please elaborate on the performance you are seeing with MK263 against steel. I gather from videos it will punch through about 1.5 inches of mild steel. I still need to purchase some so I can do my own testing.

Projectiles at 1.25 each;
https://www.gunbroker.com/item/878103276

Those definitely aren't MK263 projectiles - they don't have the double grooves. They ae listed as "Lake City" and the MK263 comes from Canada. So, maybe these are the modern M2 AP rounds? Also strange how the canalure is almost non-existent on these projectiles?

The IVI (Canadian) Sniper Elite line of rounds, including their AP, do not have a significant cannelure.  Not being intended for MG, they felt it wasn't necessary.  What the bullet jacket has is a slight mark, like shown in the GB auction listing.  (It's there as a guide to determine the proper seating depth during mfg.)

The dual cannelure AP bullets were from IVI, but LC also did their own version of Mk263, with a single, traditional, cannellure.  I've seen both MG grade AP rounds from both companies and the IVI Sniper Elite variants from IVI.

You can see the lack of cannelure in the cross-sectional diagram on the IVI website and also, to a lesser degree, in the photo of loaded rounds on their website

https://www.gd-ots.com/munitions/small-caliber-ammunition/sniper-elite/

The GB auction (not mine) examples aren't exactly Mk263, technically, but the same bullet design without the cannelures and loaded with no significant case mouth crimp.  The auction examples are IVI, but a lot of test stuff came out of LC that was produced other places as LC does acceptance testing for the military, so a mfgr could very well ship some of their ammo to LC for that testing.  I've seen barrels of the Limited Range Training bullets, for example, with LC shipper markings that were going out for scrap.  Those specific barrels had IVI produced LRT bullets in them.

So  the auction listing is partially correct.  They probably came out of LC like the other stuff he had listed, even if LC didn't make them. And they are of that new design .50 AP, but the Sniper Elite variant, rather than the Mk263 MG versions.

Yeah me and my big mouth.
He had the projectiles for $2 bucks or so if bought in 100 round lots and about a buck if bought in lots of 10 IIRC he had 30 lots of 10.
I figured someone messed up and PMed him on Gunbroker.
Said his son put the wrong price on them and corrected it.

Nice guys finish last.