[quote=@ArmorPlated]
Now that that's done, any players want to try to pin down barrel sizes so we have a guide to go by if we want a boomstick or a peashooter?
[/quote]

I'm down, I have a couple thoughts on the topic myself. 

Seems to me most people seem to be using 20mm as the standard for anti infantry/light vehicle work and point defense, which makes sense because many nato vessels use 20mm Vulcans for their close in work and point defense, but given the size of a Naval ship compared to an Arsenal Walker, I'd wager that's a bit high on the armament scale, especially given its weight and the weight of their primary weapons systems. 

I personally think it's a bit on the high end (which is why I put my sparrowhawk's pd weapon at a rifle caliber) and also a bit overkill to be used for soft targets like infantry and light vehicles. I'd suggest scaling down to a 7.62 or a .50 Cal. 

For other weapons, I tend to just take modern day equivalents and scale it up a little because future tech. Ie my sparrowhawk uses a GAU-11, which is based off the modern day GAU-8, which is a 30mm Vulcan that makes the brrrrt sound that A-10s are famous for. So since it's the future, I scaled it up to 35mm

I guess in the terms of this world, I'd consider something like 35mm to be a 'low' caliber weapon. 

Since it would make the most sense for Federation units to use similar ammunition, perhaps a 60mm shell for 'rifle' style weapons and a 150mm shell for the rail guns and heavier weaponry? Or if that seems a bit on the high side, scale it down to like 120mm?

I guess the power scale also depends on how quick AWs are taken down with conventional weapons. I assume the warriors are capable of taking at least one tank shell to the chest, otherwise why wouldnt they just stick to tanks?- tanks have a shorter profile and I imagine easier to train for, and are pretty mobile.

Walkers I guess also have the advantage of being able to function in space, but I assume the armor of a standard Walker is armored enough to take some amount of heavy fire.