Month 1 https://gladiator.tf/sales?item=Holy%20Grail%20Taunt:%20The%20Russian%20Arms%20Race&at=2022-04-29T21:53:07.809Z

1 @ 3 keys 36.77 ref

1 @ 3 keys 41.77 ref

Month 2 https://gladiator.tf/sales?item=Holy%20Grail%20Taunt:%20The%20Russian%20Arms%20Race&at=2022-03-29T21:53:07.809Z

Nothing

Month 3 https://gladiator.tf/sales?item=Holy%20Grail%20Taunt:%20The%20Russian%20Arms%20Race&at=2022-02-29T21:53:07.809Z

1 @ 4 keys 50.55 ref

2 @ 4 keys 50.88 ref

1 @ 4 keys 52 ref

1 @ 5 keys

1 @ 5 keys 11.77 ref

1 @ 5 keys 27.77 ref

https://marketplace.tf/items/tf2/30843;5;u3003

$10.39 / $1.74 = 5.97 keys

https://mannco.store/item/440-holy-grail-unusual-taunt-the-russian-arms-race

Outdated

https://backpack.tf/item/6307746458

https://gladiator.tf/listings/6237c81d12582a44ce3ac7a9

~4.35 keys

https://gladiator.tf/listings/625b34c04075c7aad3f99741

Listings from a few weeks ago shows several sellers down to ~4.75, seller at ~4.2 is very young https://gladiator.tf/listings/6269924096a86ed34a1eec71

Excluding sale below ~3.6 due to buyers, sales 5+ excluded balance this a bit.

3.6-4.75 keys.