Smallest possible time from unloaded state to loaded state.

• Battle Cannon: 3.08 Seconds.
  
• Artillery Cannon: 7.85 Seconds.
  
• Bertha Cannon: 19.10 Seconds.

How many bullets each autocannon+mg can fire every second.

• Rotary Autocannon shoots:
  30.302405889818027992150464778302
  bullets per second.
  
  
• Light Autocannon shoots:
  7.5851401642880678463481190976232
  bullets per second.
  
  
• Heavy Autocannon shoots:
  2.0167657772595137900393551673774
  bullets per second.
  
  
• Machine gun shoots:
  15.305853815626909405263499456948
  bullets per second.

Bullets Per Sec -> Sec Per Bullet
The function to convert from bullets per second to seconds per bullet is 1/x or x^-1, with x being the amount of bullets fired per second. (You may use these two functions interchangeably in this case, as they return the same.)

Example of this in use:
We have two Light Auto Cannons (LACs) on our vehicle. We want them together to fire at as low of an interval as possible. If we only start firing one of the two LACs initially, and wait exactly halfway until the first LAC is going to fire again before starting to fire the second LAC, we will achieve the lowest possible time between each bullet fired from the two LACs combined.

As is stated earlier in this guide, the LAC shoots ≈7.585 bullets per second, so we input 7.585^-1 into a calculator, and the calculator returns ≈0.132. (note that in some calculators you may have to do (7.585)^(-1) to make the calculator understand your request)
We now know that there is 0.132 seconds between the firing of each bullet from a singular LAC, so we divide it by 2 or multiply by 0.5. The calculator returns 0.066, this is halfway between the firing of one bullet and another, from a single LAC. Some methods require we know this time in ticks, so rq using x*60 we find that 0.066 seconds is 3.96 ticks.

Now that we know the numbers we need, we can pick a method to implement this delay, I'll name some of the main ways which come to mind.

• Using inherent logic block tick delay

Afaik every logic block has a tick of delay from information enters it to information can leave it, we can use that to achieve a desired delay.

Make a 1x2 microcontroller, add two on/off nodes, set one of them to output. Now add a logic block that does effectively nothing for every tick of delay you need, between the input and output in the micro. (for example an OR gate with no second input)
In our case as we know, we want ≈4 ticks of delay, so you'll want to place 4 OR gates going into each other in a line with no second input, that way there are 4 ticks of delay.
Plug your fire input directly into one LAC and into the micro, with the micro's output going into the second LAC.
https://steamuserimages-a.akamaihd.net/ugc/1818903965572349199/9F47AD3859B957759150A57F9F049B59FCCB6EB7/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false

• Using capacitors while accounting for inherent logic block tick delay

This method does not really work on a timescale as small as the twin LAC case, but I'll explain it anyway.

Make a 1x2 microcontroller, add two on/off nodes, set one of them to output. Add a capacitor between your input and output, set it's "Discharge Time" to 0, and it's "Charge Time" to as close as possible to the seconds per bullet on your gun of choice divided by 2.
To be super precise we should also remove one tick in seconds, as the delay block itself adds a tick of delay. One tick is ≈0.01667 seconds, subtract this from the Charge Time you use.
https://steamuserimages-a.akamaihd.net/ugc/1818903965572349175/29866F7E21D0FFF0FCA8338FA426134218142989/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false

• Using timers while accounting for inherent logic block tick delay

Make a 1x2 microcontroller, add two on/off nodes, set one of them to output. Add a timer block and constant number. Set the timer block to "ticks", plug the constant number into the timer, plug the input into the timer, plug the timer into the output. Set the constant number to as close as possible to the ticks per bullet on your gun of choice, divided by 2.
To be super precise we should remove one tick, as the timer block itself adds a tick of delay.
In the twin LAC case, that means setting your constant number to 3, as we want ≈4 ticks of delay.
https://steamuserimages-a.akamaihd.net/ugc/1818903965572349193/A7E65019B7E5772E64AC90B359B9A113FE4B5C13/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false

• Using a Lua timer

By getting creative, you can make a Lua program which simulates a timer or delay, and write and read your bool to and from it.
Alternatively you can just use a workshop one like this one: https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=2141294085
Make your Lua program wait as close as possible to the ticks per bullet, on your gun of choice, divided by 2.
Again to be super precise we should remove three ticks, as the composite write block, Lua block, and composite read block together adds 3 ticks of delay.
https://steamuserimages-a.akamaihd.net/ugc/1818903965572349185/1E98355F989B61BD3C5F56706E1F149AB525CF68/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false