Sale 1:

Sold for $58.64 on the SCM

http://steamcommunity.com/market/listings/440/Unusual%20Mo%27Horn

https://backpack.tf/profiles/76561198028577564#!/compare/1512345600/1512432000

https://backpack.tf/item/6258878825

https://i.imgur.com/lLhvSIu.png

No other sales near this.

58.64/2.45 = ~23.9

X = 24

Sale 2:

Sold for $48.56 on the SCM

http://steamcommunity.com/market/listings/440/Unusual%20Mo%27Horn

https://backpack.tf/profiles/76561198197338561#!/compare/1513641600/1513814400

https://backpack.tf/item/6258878825

https://i.imgur.com/T53ETu3.png

Given that the item would be tradable after 7 days, we can determine whether it sold on the 19th or the 21st of December.

We can see that on the 27th, the item was still untradeable, so it couldn’t have occurred on the 19th.

https://backpack.tf/profiles/76561198197338561?time=1514332800

48.56/2.39 = ~20.3

X = 20

No current sellers.

Going with 20-24.