Polars comment on my last suggestion, going with 500-590 keys - https://backpack.tf/suggestion/58e6bed2c440454ba767ea41

4 recent sales!

Sale #1

https://backpack.tf/profiles/76561198150077063#!/compare/1491264000/1491350400 - Sold for Beams rifleman (~600 keys, mini below)

Mini on Rifleman - https://backpack.tf/suggestion/58c0a2970e2cad383c3bc1d6 (suggestion at 602.5 ~600)

Sale #2

https://backpack.tf/profiles/76561198144034994#!/compare/1487548800/1489881600 - Sold for Scorching whirly + DBD boxcar + Alot more

ONLY recent nonbulksale on Whirly warrior - https://backpack.tf/profiles/76561198309453584#!/compare/1488758400/1489104000 - Unusable

Sale #3

https://backpack.tf/profiles/76561198150077063#!/compare/1491177600/1491264000 - Sold for BF neackwear (545) + GE private eye (sellers at 50 keys)

Sale #4

http://backpack.tf/profiles/76561198000495166#!/compare/1493596800/1493683200 - http://www.tf2outpost.com/trade/28897115

History of the Boxcar: https://backpack.tf/item/5024185618

4 sales ranging between ~400, 500, 595 and 600.

Going with 500-590 flat as of polars comment