Help Identify .50 Bullet

I got this in a grab-bag of various .50 BMG bullets on an auction site and have never seen anything like it.

Some kind of experimental bullet? It’s a GMCS bullet that weighs 685 grains. Thanks in advance for any assistance!

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Nice to see, it looks like a solid SRTA.
Is it magnetic? Then it could be even copper washed soft steel (looks much like it).

“SRTA”? For those of us what just do not know…
Thanks.

SRTA and LRTA, changing sometimes even in one presentation but now I think the SRTA could be the frangible version.

12.7x99_LRTA.pdf (653.9 KB)

It is magnetic.

Great, so it appears to be copper washed soft steel.

This means:
LRTA = Limited Range +/- 2,000 meters, and SRTA = Short Range +/- 200~750 meters?
I could not find ansolute definitions.

I have one with an orange tip. Not at hand. On my desk. Will post some pictures coming week. It differs from the shown one. Always thought short range. Thanks for the sheet, Alex.

I thought of SRTA being the plastic projectile stuff and these LRTA were good out to 1000m, but they get tagged differently.

Here is some variants

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What is the purpose of all the cannelures. And was there any compound or substance inside the fins and bullet?

My understanding was to reduce ricochets. The base is hollow and could have a tracer component easily enough, but mine are empty.

The fins were just fins to cause drag and reduce rotation to stabilization will be lost and tumbling triggered: hence teh reduced range.

The cannelures are used to form small driving bands which will reduce stress and wear to/of the bore.
Solids of any material normally shall not be “full caliber” but rather “land diameter” + driving bands, just like in artillery.

Here one more doc on the “SRTA”:
WednesdayCumberlandLuisdeSousa.pdf (875.3 KB)

Great items !!!

The original poster’s projectile is an example of AAI’s contribution to the limited range training ammunition development. (Some refer to them as SRTA, some Reduced Range, there used to be a definitive difference in terminology, but now it’s all getting blended together.)

Mild steel, copper washed. Blue designates training, as the concept isn’t a tactical load. This example is the ball, while the red tipped version is the tracer. Same bullet, just the cavity is filled with tracer compound on the red tip. There is also an example where the same bullet style is painted all blue, not just the tip. My examples are loaded on LC cases, 70’s dates, but they were an AAI project from later than that, I suspect 1980’s.

Jestertoo’s photo of loose projectiles shows AAI examples. The group on the left are just .50 Frang, but the ones on the right are all SRTA/LRTA variations trialed.

To produce a bullet that falls out of the air in a shorter distance than tactical ammunition has been pursued for decades. Several companies have been involved. Bullet designs have relied on tail fins, nose fins, flutes into the body of the bullet, probe-like sections on the nose of the bullet in various lengths, plastic nose tips that blow off leaving a blunt bullet nose, etc. Anything to get the bullet to create drag.

Currently NAMMO, RUAG and IVI (SNC)/General Dynamics have designs in play. (Not counting the blue plastic SRTA rounds from BF/DAG, M858 Practice and M860 Practice Tracer.) In US service, the IVI .50 design is in use, Mk322 Reduced Range and Mk321 Reduced Range Tracer. The Mk322 and Mk321 have had tip colors in Blue and Red/Blue, but were last reported to be Orange and Red/Orange. Not sure why the tip colors were changed from what most considered standard.

A smaller caliber Reduced Range tail-finned concept, using frangible bullet materials instead of metal, is under consideration by the US Coast Guard for drug interdiction applications.

Thank you all for the information!

Pictures of the one on my desk. The bullet is strongly magnetic except for the orange tip. Base is hollow. Tracer? Quite possible.

This would be the MK 322 Reduced Range (Ball), the tracer would have Red and Orange on the tip. Unlike the original poster’s example, this version is a copper jacket over a mild steel core, the core extending out the back in the form of a fin section. (There are also blue tipped examples of this exact same projectile, prior to the Mk322 designation.)