[Mobhack]

Artillery is an attritional weapon - in order to achieve killing effect, especially on dug-in troops, it needs to be applied over a significant time. In the game, that means like 5 moves plus of application. And quantity has a quality all of its own WRT arty, and size does matter.

Lesser applications will produce a significant suppressive effect, which can be exploited with an assault into the stonked zone within 1 move, maybe 2 in order to sweep up the stunned troops who will likely be cowering in their tranches in "retreat" status. That is effectively "neutralised" in army parlance - routed (or severely suppressed) troops in trenches will tend to stay in these, rather than run out into the barrage. They may run if they know of enemy within 5 hexes or so though.

So if I am assaulting, I lay on the arty where I think the enemy is, and either run tanks with riders or mech inf into the zone, even walk in sometimes. The key here is control of the arty since you are "leaning into the barrage" by keeping very close behind it, so stray shells may wander into your assault group - so it is best to have a FOO right up with the attackers, using an AOP AFV (APC or FOO tanks say). In MBT you have FOOS with Thermal Imagers, or Ground Surveillance radars who can spot through the smoke and dust of the barrage - very useful.

Mechanised infantry,or tank riders, have the advantage that the carriers can stay that bit further behind the barrage compared to walking grunts, and then run in and poach the objective.

But if you just pound the ground and expect the enemy to be slaughtered - that wont happen. See WW1 for days-long barrages that left surviving defenders able to get their act together when the barrage lifted and set up a "reception committee". German storm-troop tactics, and the Canadians who were prime exploiters of "keeping right up with the barrage" tactic and so got in while the enemy were still neutralised did better in WW1 with quick neutralising barrages and then in with the bayonet ASAP.

So combined arms - neutralise with shed-loads of HE bricks, which do not have to be high-calibre "cratering" ammo, smaller sized HE is better for the troops leaning into the barrage in fact since drop-shorts are less lethal and the blast circle is smaller so letting dismounts get closer to the barrage line (which is why the 25 pounder was designed post WW1 by the UK). Then in with bomb and bayonet for the kill, using mechanised transport if you have it.