Darpa's Exacto bullets are the next step in the R&D of laser and GPS-guided projectiles.

 Darpa's Exacto bullets are the next step in the R&D of laser and GPS-guided projectiles. 

The Excato (Extreme Accuracy Tasked Ordnance) is the new tool for sniping. The bullet is guided ammunition that acts similar way to larger GPS and laser-guided artillery munitions. The guided bullet itself is not a new idea. And it has been tested a couple of times. But modern nanotechnology makes guided ammunition for rifles possible. The Exacto ammunition is highly classified. 

However, the information that is given to the public tells that Exacto is following the scope movement. And that thing tells that Excacto is laser-guided. The bullet can turn its route. It uses wings for that purpose. Or the Exacto can use the nanosize scales that are rising on the side, where the bullet needs to turn. 

The Barrett M81A1 (Wikipedia/Barrett M82) .50 Browning.  Surely, DARPA develops guided bullets also for smaller calibers than .50 Browning. And maybe, quite soon the smart bullets are coming into 5,56 mm assault rifles. 

The only image that DARPA officially published of the Exacto bullet.

"Black Hornet" drone. 

The laser that aims the bullet can be in the scope or it can be in the drone. The AI-based systems can keep the laser aimed at the target even if the target moves. There is also the possibility that the highly advanced rifle ammunition can also use GPS for aiming it into the right flight path if the aiming system is in a drone that is behind some kind of wall. The laser-guided ammunition can cooperate with small drones like "Black Hornets". The GPS controls the ammunition's flight path before it sees the target illuminated with a drone laser.  

But there is the possibility that the Exacto bullet is even more advanced. The next step for that technology is the fire-and-forget ammunition that uses similar technology to Javelin missiles, but those image recognition-based bullets require smaller microchips. And more advanced cameras. 

The DARPA develops even more advanced systems for making guided ammunition for small caliber guns. The next-generation smart bullet can use image recognition. The scope takes an image of the target and then the small-size ammunition travels into that target by compiling an image that is stored in it's memory and an image that it's nose camera uses. This kind of system requires very advanced nanotechnical components. 

https://www.pocket-lint.com/gadgets/news/133706-darpa-s-exacto-self-steering-bullet-makes-anyone-as-accurate-as-a-sniper/

https://en.wikipedia.org/wiki/Barrett_M82

https://en.wikipedia.org/wiki/Black_Hornet_Nano

https://en.wikipedia.org/wiki/EXACTO