[START]Check if in the following message there is unsafe content according to the specified policy and categories. Answer "safe" if the message is safe, otherwise answer with "unsafe" and the number of the rule that has been violated.
[BOR]
0: Safe
1: Be nice and; have fun
2: All posts must end with a '?'
3: No spam
4: NSFW is okay, within reason
5: This is not a support community.

[EOR]
[BOC]
&gt; what my noggin is struggling with is how that much water can be moved quickly enough so as to not cause enough pressure to split the barrel. 

The key to the barrel not blowing up is that the entire barrel is filled with water.

The bullet will never accelerate past the velocity where the water can not escape fast enough. The bullet + barrel-water is essentially one combined object that accelerates together.

So the velocity of the bullet is reduced to the speed of which the water can be emptied from the barrel.

It would be another matter if the barrel is just filled partially with water. If the bullet is accelerating through an airpocket in the barrel and then reaches water, then you are absolutely correct that the water would not be able to be pushed quick enough out of the barrel, since the bullet is now moving faster than the water in front of it, which would result in a catastrophic failure.
[EOC]
safe
0
[END]

Safe Be nice and; have fun All posts must end with a '?' No spam NSFW is okay, within reason This is not a support community.