50 Caliber M17 Tracer
The M17 tracer is an old design, having been around since early W.W.II. It is a flat
base design with the entire back surface being tracer compound. The base is sealed with a
copper or plastic disc to separate the tracing compound from the gunpowder. Tracer bullets
with their element exposed the the powder have a very short shelf life, as the fumes from
the powder 
react with the tracer igniter element and render it inert. Length of trace is
1600 yards minimum. Bullet weight is about 648 grains, with a maroon tip color.
These M17 bullets have been pulled from US GI W.W.II dated ammunition on the "old style" bullet pullers. This machine splits the case neck and then gently removes the projectile. As a result of this operation, there is 1 small line on the projectile from a point just slightly ahead of the cannelure down to the beginning of the boattail, leaving only a negligible mark sticking out of a loaded case. These projectiles have all been run through a set of draw dies to insure proper diameter, and eliminate the high spot caused by the split line.
M17 Tracer bullets were designed to be loaded with IMR-5010 powder. This is an extruded IMR type powder, and burns hotter than the ball powders used to load M33 and M8 ammunition. We use these bullets in a M2 machine gun, with the 45" barrel length. Even using ball powder, we are experiencing 100% trace. However, when shot out of a 24" barreled rifle, this same load only lights the tracer about 50% of the time. Switching to IMR-5010 increased the number of rounds that traced to about 80% in the short barreled gun.
The M17 tracer burns for a long, long time! About 2500 yards. These bullets have the nasty habit of jumping out of the backstop and flying up into the air several hundred yards in a slow gigantic arc where they can be seen for miles around, and then falling back to earth and lay there burning like a road flare. Lots of fun if you are in the desert with nothing to catch fire, but very embarrassing if you are at a local gun range where the surrounding neighbors would like nothing better than an excuse to shut down the operation!
Just a little something to keep in mind.
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