Does anyone combine A314 and the ammo cologne together? Not sure if this combo might be overkill and produce negative effects or not?..any advice would be appreciated.
There are a lot of users, especially the matured ones have tried that combo with a lot of success. Age is a factor here.
I suggest that you give that blue “Search” button some press and clicks and I’m sure you’ll find the posts about that combo.
Anyway, you can also test it. Just make sure that you know your sweetspots for both first. 
Yes - it is a popular and effective combination and a search will reward you.
For younger guys, using a small amount of A314 to steer the Ammo is a very viable for all-round attraction with underlying status and higher proportions of A314 are viable in professional and overt status situations. As you/your targets age, the proportions of each you can use effectively will also increase.
If you are using the sprays, they will layer together just fine but if its A314 oil, you will probably find it best to keep the oil and spray points slightly apart.
I’ve used this combo quite a bit. Definitely a cool combo to use, but I would suggest going Very light with the a314. I once wore 2 drops with 2 sprays of Ammo. Bad idea, very bad idea. Make sure to test in small doses first. Trust me you don’t want women walking past you with their heads down and refusing to make eye contact with you. Other than that have fun and happy testing!!!