So here's a thought....what if guns in 40k were closer to realistic in their range?
My reaction? The assault armies would be torn to shreds most of the time.
A real railgun doing its thing.
Let's put together some simple numbers. A space marine is 28mm high and in the fluff is portrayed as just over 2 metres tall (7 feet give or take). One inch is about 25mm and so it's reasonable to determine that compared to a marine, it represents about 2 metres (he's slightly taller than that but is 28mm so close enough).
That means that a boltgun has an effective 'real world' range of 48 metres (24 inches). That is not a long way by any means. In fact, most modern pistols would be more than capable of hitting a target at that range, albeit with some accuracy challenges.
Some quick googling suggests that rifle weapons might typically engage at 300 yards max (http://www.angelfire.com/art/enchanter/range.html) so we can knock that down to 200m just for the rounding and to represent the marines typically engaging at closer range because of their style of combat. However, these are the finest soldiers who are geneticall. enhanced, equipped with the best technology and conditioned to fire with deadly accuracy. Still, we'll keep it to 200m to play safe and easy.
200m/(2m/inch) = 100 inches.
That's right, the range of a boltgun should be 100 inches!
Now we can mess around with this for all sorts of other guns too. The lasgun should be similiar, Tau pulse carbines a little longer perhaps, snipers would be the terror of the battlfield by firing at 200inches and the big ordnance guns are just crazy.
Let's bring it around to my other army of the Tau. Our railguns have a range of 72 inches, which reaches out to a measly 144 metres. Even pistol rounds could go that far, albeit with low stopping power and accuracy.
Taking the rather groovy picture that opened this article into account (that flame is plasma left by the sheer energy of the railgun round passing through the air), we'll use the US weapon's development style of pushing a 2kg projectile to 3000 m/s as a rough idea of what our hammerheads and broadsides can do.
At 3000 m/s, the railgun will put a shot into a tank at 1km distance within .33 seconds. That's pretty nasty. Given that the M1Abrams tank engaged Iraqi tanks effectively at 4000m (http://www.fas.org/man/dod-101/sys/land/m1.htm) during the first Gulf war, I don't think it's unreasonble to use 3km as our railgun's engagement range.
So my broadsides have a 1500 inch range for this game, all good?
When you step up to the Basilisk, you start to realise that certain models should almost never be fielded on a 40k table. The damn thing has range in the 10's of km. Ideally you should be able to call down artillery fire from the IG player whose playing on the tournament table at the other end of the hall. Of course, to make the most use of this kind of ranging, you would have to agree to play 40k on much much bigger boards. I think that the use of cover would quickly become more prevalent than it already is.
So who's interested in playing some nasty, shooting 40k with my Tau army now?