Some people wonder why the better guns are not used as much (SMR, SCAR, Chicom, Five Seven, just to name a few.). I have explanation for this.
When the game first game out, people weren't biased about guns, as they didn't know what awaited them later on in the game.
Someone got to Lv55, unlocked the AN-94, and did good with it. People followed this.
Weapons like the SMR got overlooked, because people didn't use it. They used the M8A1, which was very close to it unlocking wise.
Quickly the most used weapons became things like the KAP-40, B23R, AN-94, M8A1, FAL, DSR, Ballista, and so on.
Very few people decided to use the SMR, M27, SCAR-H, MTAR, Type-25, TAC-45, and so on.
When people wanted diamond guns, they were forced to use these weapons.
They learned that the overlooked tier of weapons, were some of the best, but they didn't tell anyone because they didn't want to look uncool, or like they were a bad player.
After the Diamond-surge, people went back to using the same old guns that they did before.
I decided that I wanted to get Diamond ARs, and I did get them (Reset stats soon after, mostly by accident)
I still have the time it took me to get each AR gold in my mind.
MTAR - 3 Days
Type-25 - 1 Day
SWAT-556 - 4 Days
FAL OSW - 3 Days
M27 - 3 Weeks (I hate this gun with a passion)
SCAR-H - 2 Days
SMR - 1/2 Day
M8A1 - 2 Days
AN-94 - 5 Days (I had a bad time with Ronin, for whatever reason.)
SMR was the easiest. It is my favorite gun. Before I reset I had over 2000 kills with it, and more than a 2.00 K/D with it.
I use the unused, and understand how they work and why they work.