This is for hardcore players who hate to waste men, and especially hate wasting artillery who cost so **** much haha, its the simplest way to save you some men, and their are other solutions to the problem i will talk about, but this is a very easy one, also well equipped armies are the best benefiters from this tactic.
you have a Gatling gun, or an armstrong cannon, your defending (sometimes works with offence) but placing the artillery in the safety behind your infantry means your infantry can be picked off by enemy artillery who are out of range of your artillery but have your infantry in range, quite hard to describe haha.
) | [ #
) | [ #
) | [ # <--- these enemy artillery [#] can shoot your infantry [|] line on the far left, but are out of range of the close brackets: )
so you can let your men be picked off or endanger your artillery by moving them forward slowly under fire.
Solution: it is totally fine to have your cannons (unlimbered) about a metre in front of your infantry line, this means they are at the very front of your army yet don't have any trouble from cavalry who will get blasted by the infantry and wont survive the charge. You get the benefits of being able to hit any artillery who come into range without having to worry about the enemy being able to wipe them out before you can effectively pull them back to safety behind an infantry front line. So you now have a infantry/artillery combo that is most effective with gatling guns against infantry, the guns shoot at the same time as the infantry with not losses to the gat-gun team even though they are in front of the shooting.
possible problems: enemy infantry can really pound your artillery when shooting at your combination, this is pretty easily over come with G-guns because the combination wipes out anyone in front, but cannons can take longer to clear the infantry shooting them so the enemy wont run as quickly and you can lose men while they shoot you.
another possible issue is if the enemy out-gun you and before you can take them out they start shooting your artillery, this means they also hit your men, so a double loss occurs unfortunately, but the benefits means you may be able to wipe them out before they can even shoot.
Another little thing, if you want a maximum amount of firepower, put an infantry artillery combo, and then have revolver/carbine whatever missle calvalry behind that. this means three layers of point blank fire for anyone who comes too close, perfect for when melee attacks are incoming, or when an enemy rifle unit comes very close. ive never tried it in multiplayer but i dont see how it couldnt work if your careful.
Thanks for reading all this endless detail, hope it helps! if i makes no sense ill make a pic of it just ask