Now I have been searching a while now for an answer to this question. One particularly helpful site was this: LINK
However, all this site told me was that:
Mann Co. Supply Crates and other usable items drop on a separate
timer, meaning that these items do not affect the interval between
regular drops.
So, I followed a link to this site: LINK
However, I looked at the wikia page's contents, but there was nothing stated about the drop rate for crates. I am referring to different types of crates too, not just normal ones.
With the new update, Munitions crates #82 and #83 have been added into the game. Do these crates have a different drop rate compared to other crates. In addition, the Strongbox crate, #81, went 'rare' on the 27 of February. How rare is 'rare'? Salvage crate rare?
In other words, I would like to know how the drop rates for the following crates work:
- Standard Crate
- Series #81 – Mann Co. Strongbox Crate
- Summer, Fall etc. cooler Crates
- Salvage Crates: #30, #40, #50
Best Answer
Although I cannot give you specific drop chances, I will say that crate drop rates happen independently of all other drops. They are random and only certain crates drop at certain times. On top of this, there are two kinds of crates: active and retired. Active crates are still available to drop randomly, retired do not drop at all anymore. Among active series crates there are three drop rate types, common, rare, and uncommon. Pertaining to your question specifically:
Standard crates (i.e. Mann Co. Supply Crates) are not really dropping any more, the crates you will commonly see drop nowadays are Mann Co. Supply Munitions, series 82 and 83.
Between January and February of this year Strongboxes were part of the common crate drop list but since Feb 14 they are part of the uncommon series. Again, I've found no hard data on their specific drop rate but is is fairly infrequent.
Summer and Fall 2013 crates, along with Robocrates are also still dropping, albeit at the lowered rate Strongboxes are. They may drop somewhat higher or lower, I cannot say for sure. Either way, less often than Supply Munitions.
Salvage crates are not part of the active series any longer and have not been since 2013.
I realize most of this is information you can already see and probably already have seen on the wiki, but there hasn't been much publicly-made information about the subject. The item drop system link I provided does give some insight on how many opportunities a player has to receive normal drops, but we can only guess about crates.