Fix.

Sale 1: https://backpack.tf/profiles/76561198139171368#!/compare/1497744000/1497830400 - QS, for 51 pure.

Sale 2: https://backpack.tf/profiles/76561198066171590#!/compare/1498694400/1498780800 - Use on Veil.

Sale 3: https://backpack.tf/profiles/76561198172573626#!/compare/1494547200/1494633600 - QS, for 55 pure.

http://www.tf2outpost.com/trade/29176389

Sale 4: https://backpack.tf/profiles/76561198274006625#!/compare/1497657600/1497744000

Sold for a Clean Green Energy Ye Olde Baker Boy (59 keys)

Additional by the King:

The quicksale at 51 is actually 49. Other sales:

~75 in unusual weapons

https://backpack.tf/profiles/76561198045399485#!/compare/1499644800/1499817600

Grail Fresh Brewed (seller at 48)

https://backpack.tf/profiles/76561198045399485#!/compare/1500854400/1500940800

Bulk

https://backpack.tf/profiles/76561198081213486#!/compare/1500681600/1500768000

Stormy Gatsby (14) + 53 keys ----- 67 keys total

https://backpack.tf/profiles/76561198179707937#!/compare/1500249600/1500336000

https://backpack.tf/profiles/76561198081213486#!/compare/1500249600/1500336000

So there are sales at ~48, 49 (qs), 55 (qs), 59, 67, 75. R+ubi lowered to 55, so that doesn't seem like a quicksale point. Removing the quicksale at 49, plus one sale in both ends, we are left with 55-67.

55-67 should work here. The high-end is based on a mostly-pure sale, so that's why it should be included despite sellers for lower.

55-67 it is!