In the campaign I'm running I'm planning on having a combat at the platoon level ... 6 Guard squads vs an equivalent number of evenly matched foes. I wanted to use the Formations rules from Enemies of the Imperium but I'm finding the results a little skewed.

My experience running some practices of this encounter show that the 10 man squads seem to truly annihilate each other depending on who wins the initiative. A 10-man Guard squad would get +50 to their role, resulting in quite a few hits. I get with massed fire you will get more hits but the probabilities do not seem to scale well.

I understand that the Formations rule is used to speed up mass combat, but is it on the same time-scale as the PCs? Is 1 round of formation fighting equivalent to each PC taking their action? I could see keeping the rolls as GM secret and dealing the results of formation combat out over two PC turns narratively but that seems to minimize the actual impact the PCs are making in the fight.

I'm experimenting with maxing the per-underling bonus to +25, and using excess characters as simply wounds the unit can soak before bonus starts to degrade.

What has your experience been?

I ran some massed combats. My players had entire platoon at their disposal. They are from Tanith 1st and Only.

They had 10 man guard squad consisting of 2men heavy wpn squad with thread fether, and a sergeant.

5 man storm trooper squad - 3 troopers, 1 grenade launchers and sergeant.

Also they picked up 7 scintilian fusiliers along the way. Plus they had 2 chimeras. Quite the fighting force.

They had several encounters.

First they had to destroy enemy flakk battery. I speak the numbers from the top of my head.

2 flakk trukks

1 grot bomb launcha

10 gretchin mob+runthers or maybe two

some meks and lootas

10 shoota boyz

They managed to sneak, leaving chimeras turret down behind the hill, and then opened fire on them from about 150m or less. They mowed them down pretty quickly without much loses. Some fusiliers where hit i think. Maybe one chimera got hit by a rocket and lost few hull points.Moving on.

They encountered massive battle. A charge of orks on guardsmen lines. Because the commanding players was drunk, he acted to late and didnt counter attacked in time, and the guardsmen where overrun.

1 battlewagon

5 lootas

5 tankbustas

some slugga boys and gretchin

A lucky hit from rocket launcher managed to jam the kannon on the battlewagon, so he proceeded to ram them. The forward scouts managed to jump on the wagon, and throw tube charges inside, killing the crew, they were little injured in the process.

Tankbustas inflictet biggest casualties on the storm troopers and fusiliers because of twin linked launchers I gave them so they were able to hit something.

Last fight they encountered

3 killa kans

5 stormboyz

2 trukks, one with tankbustas

3 nobz and warboss

2 mobz of 10 gretchin with bomb squigs

Kans are one shot kills, they immobilized boss truck pretty quickly, and managed to slow the other down. Warboss died after two headshots from long las. Stormboyz killed some ghosts, psyker managed to dominate some of them, or even the nobs. Dominated trukk driver ran over some gretchin and boyz. Squigs blew up, killing something. 1 FP burned on the players. Storm trooper sergeant killed by ork nob with power klaw, but ghots sergeant somehow managed to hold his own.

Overall loses - all fusiliers, 2 ghots and seargeant survived, all storm troopers.

The ghost managed to live so long because of the IMBA OP camo cloacks, and therefore inability for orks to hit them.

Fighting is quite fast because you treat them as one being, so one roll etc. +50 is reasonable option. Ork special rule da toughest etc sometimes works, but most of the time dont. Orks are much too weak as a formation, normal guardsmen has to hit or several times before dropping him. It works fine with gretchin.

10 man squad in my game gave only 35 bonus to hit, because sgr is a seperate being, and two men fired from missile launcher (one was reloading, the other fired, so they could shoot every round). Without camo cloaks, they drop like flies, and can dwindle very fast. In my opinion using those rules is fun, but really situational. I dont reccomend using it on every day basis.

Formation on Formation combat will definitely lead to quick depletion of those formations. The high bonus to hit and the low threshold for meaningful damage guarantees that mooks will be dropping like flies. You can mitigate this somewhat by tossing in environmental penalties (smoke, darkness, etc); you can also grant the Formations cover AP. When I did this, I just added the cover AP to the Formation's AP, and it seemed to slow down attrition substantially.

The Formation system isn't designed as anything close to a full war game; have you considered scaling back the encounter? Fewer Formations of higher damage/armor troops will cut down on bookkeeping, and might mitigate the first shot effect. I'm not sure capping the to-hit bonus would achieve what you're looking for; I'm concerned that it would just lead to situations where a squad is hosing someone or something down with fire and totally missing round after round. I suppose you could have Formations inflict a hit with every other DoS instead of every DoS. That way, they're still hitting consistently, but not in such volume.

I ran my game session that had this huge platoon vs platoon combat and it actually went really well. It was 6 squads with Chimeras and a command squad vs 6 enemy squads with wartrukk analogs, plus leader characters. The platoon was to setup an ambush for the enemy army, which I let the characters plan with the idea that their actual characters wouldn't be in charge of this type of thing. Their actual characters remained hidden for the first few combat turns, as the GM I took general control of the friendly squads while each player got to control the Chimeras. Eventually, when their actual squad joined the fray I narrowed the focus of the encounter to just what they were doing, abstracting away that which was going on elsewhere on the battlefield.

The formation combat went well because I built an Excel spreadsheet with formulas that basically did the whole thing for me. Addtionally, to allow a little more survivability of the squads, I added a "cover save" in formation combat. On a D6, a 4 or 5 gave the target a soft cover bonus of 2 AC while a 6 gave it a harder over bonus of 4 AC. The squads whittled each other down, with a few powerful rounds. I think it was good, because if it actually stretched further, the whole enounter would have gotten clunky and stretched too long.

Well, I was never a fan of that kind of combat and I do not use it. If I want a fight on such a large scale I break it down for the PCs. If you stay in an urban combat scenario your force might consist of several chimeras and squads but you wont really notice them because they fight in another street or are behind you. And the Idea with the spreadsheet is nice though in that case I could have thrown a dice in the first place to determine the outcome of such a large battle and its losses or I might just consider making huge battles narrative.

But maybe that is because we all played the tabletop and everyone of us has the feeling that OW just does a very bad job at simulating a bigger fight that requires more than the PCs Squad with decent NPC support if deemed necessary.