Differences between M2 and M33 Ball


Hi to all,

Could anybody tell me the difference(s) between the .50 BMG M2 and M33 Ball cartridges? Do they differ in bullet style, powder loading, priming, material or a combination of those or are there other differences?
And what was the reason for the changement from M2 to M33 ammo and was this changement a NATO or a US Army led decision?

Kind regards,




Too bad that some of the resident 50 BMG experts do not particpate on the Forum. But, nevertheless, I believe the difference betwen the M2 and the M33 is that the M33 has a slightly lighter bullet at a slightly higher velocity. Why and who? I have no idea.



Hi Ray,

Thanks for your answer! Hopely those resident experts will soon be residents of this forum :-)



Cartridges of the World, 6th edition shows M-2 ball having a 709.5 gr. projectile at 2,810 fps. vs. M-33 Ball having a 661 gr. projectile at 2,910 fps.

I may be mistaken but I think that the M-33 is lead cored and flat based vs. the M-2 being boat-tailed with a steel core. In my service days (1987-1993) we only saw M-33 ball once on a training exercise. All other isssues, including combat issue during Desert Storm, were of WWII vintage API/APIT! I surmise that the M-33 was designed to be a less expensive cartridge for training use.



Yes, the difference between the two is prinicpally weight and muzzle velocity.

In its history, the .50 BMG caliber has trended to lighter and lighter weight bullets, which yielded faster and faster velocities. Faster velocities were desired as, up to the Korean War, the .50 caliber was the principal caliber for aircraft. As aircraft got faster and more maneuverable, hitting one with a bullet launched from another aircraft became more difficult, requirng shorter “times of flight.” Eventually the BMG was just replaced by 20mm cannon.

The actual trigger for the change in bullet designs was the role of “Ball” ammo in this caliber. Ball and Tracer are the training rounds, and needed to be a ballistic match to the tactical round. Prior to the M33 Ball, M2 Ball was the standard as it was a ballistic match to the tactical M2 Armor Piercing round. M2 AP wasn’t made after WW2 in the US, being replaced by M8 API. So, with M8 API being the tactical round, the M2 Ball was no longer a match. That necessitated the creation of a new Ball round, the M33.

First lots of the M33 Ball in the US were manufactured in 1951, with last lots of M2 Ball being produced in 1950.

Besides weight between M2 & M33 Ball, the M2 Ball has an exposed steel core at the base, with a lead point filler inside the copper jacket. The M33 Ball has a base plug of lead covering the mild steel core, with an inert point filler material inside the copper jacket.

All the .50 Ball rounds are mild steel core, not lead, since the first “production” models in the 1920’s.

Keith Pagel
Fifty Caliber Shooters’ Assn.


Thank you all for your answers!

Keith, that is a clear story you’ve wrote. So the change from M2 to M33 ball training round was made because of the change in tactical round (M2 AP to M8 API) and their different ballistic properties.

Thanks a lot, it’s all clear now!

Best regards,