Introduction
A 7by7 single barrel interdeck gun (tnt cannon) designed for usage in movecraft with a single redstone input from the center of the base. It features the standard half tick trigger (allows for 8 arcs in total, increasing the repeater increases the arc, and a half tick more delay can be added by clicking the purple button). High spread (high vertical spread, meaning the tnt forms a vertical line in which they fly in, created using water stream to displace tnt in certain ways). It also has the potential for armouring on the top of the gun (with an example given, is really only useful when there are blocks that has movecraft combat override making them able to TANK other tnt shots). A highly efficient ppl (propellant) chamber design, allowing for all ppl to be concentrated closely to the pj (projectile) with minimum tnt ray blockage (using the water-locked chest, more than half of the tnt entity box is within water, meaning it cannot destroy the things around it). The download has the gun without any tnt in it, so you will have to manually fill it. Plus, it is vanilla friendly, meaning it can used in a vanilla world without issue.

Youtube
There is a youtube link showcasing how the gun works, the cobweebs spawned shows the trajectory of the projectile. This won't affect the performance of the gun in vanilla, it is mainly visual.

Specifics
Projectile: 36 tnt
Propellant: 19 tnt
Range: 320 ish
Arcs: 8 standard arcs
Type: 7by7 single barrel interdeck gun