stark ar : dmg-18 magazine size-27, burst delay- 0.07s, fire rate-857, reload time-2,1s
br-16: dmg-17, magazine size-30, bursr delay-0,075s,fire rate-800, reload time-2,0s
soo wtf i have my best br 16 kira in cobalt but i think i am going to use bronz cards 
because stark seems to be just better
I find them pretty equivalent. Sometimes the extra three rounds in the BR16 is amazing. Other times I like the slightly more damage the Stark can pull off which can be the difference between killing somebody in once burst or two. They are both good IMO but I slightly favor the Stark mostly due to the situations where I barely kill somebody compared to them barely surviving. But that’s probably just a placebo thing.
The BR-16 is more consistent and has better magazine capacity which, even though it’s just one more click, you will feel once you play either enough. The damage difference is negligible, with the BR-16 actually edging out in DPS (at least according to the Wiki). The BR-16 is simply going to be easier to track with the longer burst whereas an error with the Stark will be much more tragic for you when your burst has less room for error. It’s personal preference, though I do prefer the BR-16 out of habit.