U.S. 7.62x51, M59 vs. M80 Ball


The M59 Ball bullet is GM with a steel core and a lead-antimony point filler, 1.28 inches long. Bullet weight is 150.5gr. Complete cartridge weighs 388gr.

The M80 Ball is either GM or GMCS with only a lead-antimony core and is 1.14 inches long. Bullet weight is 149 gr. Complete cartridge weighs 388gr.

My question is how can you differentiate the two without pulling the bullet? Was there an overlap in dates of manufacture or can this be used to seperate them. If they do not overlap in date, what are the date ranges of each type.


Steel core M59 will attract a magnet and the lead core M80 will not.


Only partly true. GMCS M80 will also attract a magnet. If it is a GM M80, then, yes, that seperates those out. The magnet test is what I had been using until I found out that part of the M80’s have GMCS jackets.


Doesn’t the M-59 have a “French” cannelure like the AP? Or am I mistaken?




Great question and I am looking for the answer myself.

It’s been said that you can tell by moving the magnet all around the bullet to determine if it’s only the core or the entire jacket that is steel. In theory, the magnet should not have as great an attaction at the tip if it’s a steel core only. I’ve done this but have never been satisfied that I can really tell a difference. Maybe others are more confident with this technique.

The best way is to get an expendable sample and pull the bullet.



I’ve also noticed the effect Ray talks about (weaker attraction at the nose) when using a very powerful magnet.


I’ve had pretty good luck differentiating between GMCS and steel core GM by using the edge of a relatively weak refrigerator magnet. A narrow, weak magnet allows me to “sample” narrow slices of the projectile, so to speak. Using this method it’s pretty easy to feel the dropoff in attraction as you move the magnet towards the tip of a steel core projectile. The attraction should of course feel equal all along a GMCS projectile.

The key for me is the narrow, weak magnet. Otherwise I have a hard time feeling the difference.