Clear "Plastic" .50 BMG & other variants

I was at a friends house looking at several rare and experimental ‘One Off’ S&W Revolvers, and noticed this catridge in his show case. He has a couple other interesting rounds, up to 20mm, (and maybe a 30mm I could not quite see), and was surprised when I set this one out as a live round- he just never paid attention to them. Found out several are live [as in they evidently have powder and a live peimer] including that little .5 Cal spotter cartridge for the Recoilless Rifle.

Anyway, any information I can give him on this brass base, clear plastic body, brass neck/shoulder, with an odd steel projectile, would be greatly appreciated.
Also, I just noticed the No. 032414 near the base of the cartridge- In my defense, I did not have a magnifying glass, and was running late!
Edit 1: Oh, yea, definitely not a magnetic projectile.
Edit 2: Directly above the numbers on the base in the plastic, No. 000404.

As always, much appreciated!


Frangible 700 gr Wide Taper Point load by Engel Ballistic Research, Inc. Case made by MAC, LLC.


left a prototype mock up LC 09 open primer (of no significance) (no clue “who’s”)

left 2 easy for me to assume AMTECH…this one not a display dummy…live primed LC 85

left 3 my note says Navy consideration MK323 BYS 13

left 4 my note USCG “for taking out motors” BYS 10

left 5 different projo…note case “notch” to accept plastic link BYS 19

left 6 (or far right) said plastic link on fired case BYS 17

3-6 all with sky blue primer annulus


Any idea what ‘BYS’ stands for, other than ‘Bust Your Ship’? :wink:

Again, my thanks to both you and Pepper.

It’s the DoD 3-letter manufacturer’s symbol assigned to MAC, LLC, Bay St. Louis, MS. Strictly speaking, it has no meaning, but It was evidently chosen from a list of available symbols because the letters match their location (B a Y St. Louis).

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These codes are assigned by DOD but a new manufacturer can request a code that is unused. IMI of Israel has a number of codes, but I don’t know why. Companies apparently have a different code for each different facility.

The codes have no “meaning” to DOD but the manufacturer may have a reason for requesting a specific code.


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Lew, I am not sure how it really works when codes are issued but for example NICO (Rheinmetall subsidiary) is using a differnet code than usual when delivering 40mm and flashbangs to the US military. All info I received from there was “as per US request we are using a different code”.

I still have not figured if there is a central NATO or US entity that is issuing the codes.

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These were strictly US codes and MIL-HDBK-1461 listing the codes was publicly available through 1999. Then in about 2000 it was put behind the DOD firewall like most other DOD material and was only available to ,mil addresses and approved contractors. The document was under control of the Army, an office at Rock Island I believe.

These codes are used by the Army Single Manager for Munitions (I think they are still called that) and there are a number of reasons they may decide to use a different code for different munitions. If NICO is a different facility from RM then that would require a different code.


Lew, Nico is still using “NIC” in Germany while Rheinmetall itself is using RH or RHU.
Same with “Pyrotechnik Silberhütte” who also is a Rheinmetall Subsidiary and is using the code “PSH”.
Other Rheinmetall subsidiaries are Arges (Austria) who is using “AG”. And same for Oerlikon (Switzerland) who is using “OE”.
And German Buck is using “BCK”.
All are Rheinmetall subsidiaries who are usig their own codes.

And for what ever reason the US have decided that Nico shall not use “NIC” for US DoD contracts.

Alex, assignmet of new DoD manufacturer’s symbols is unrelated to the NATO and managed exclusively by APSA (Ammunition Procurement and Supply Agency) in Joliet, Illinois. Since symbol “NIC” was already assigned to another manufacturer, Nico was assigned with symbol “NPG”.

Two things to keep in mind regarding US DoD symbols is that:

  • Same manufacturer having plants at different locations result in different symbols.
  • Same manufacturer having different plants in the same location result in different symbols.



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Fede, thanks a lot"
So the issue of NATO codes is still a national issue I understand!

EBR may have loaded that round or not. The projectile is Sinterfire and I believe available to purchase by anyone.

There was a big effort for Plastic Frangible. 50 BMG for helicopter support.

A little while ago MAC was looking for a production manager. Any takers? Listed on Indeed.


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Witt Engel indicated to me that he loaded them! They were loaded with both frangible and normal ball bullets.

I think they were intended as Sniper loads to cut the weight carried by a Sniper team. That is a vague memory from a conversation from over a decade ago!

This is the label:



Dec '15

Yes, it is military adopted, Mk is a USN designation, as opposed to Army M# and USAF PGU designation, project was driven by the USMC actually, with USN contracting office.

Projectile is just the standard M33 Ball, the reason for the differing designation is due to the polymer case.

BYS is Bay St Louis. That’s confirmed. My info came from the case mfgr and USN/USMC sources.

Brian, great info, thanks a lot!

it makes sense that this was for the Marines.
Witt Engel did a lot of work for the Marines including a LMG with a special 6.5mm case that never got funded for advanced testing. I’m not sure who developed the LMG but he did the cartridge design.


Lew, 6.5mm?
Are there any illustrations available?