How armour & shield are effective in Chainmail MtM ?

[snorri]

I was tinkering Weapon vs Armour in Man-to-Man Combat in Chainmail, to understand how effective are Shields and Armours.

The maths behind the Shield table is difference betwwen the score to hit with and without shield :



The maths behind the Armour table is difference between the score to hit without armour and with this Armour type :



I also included the average in both tables. Please remember these tables are on 2d6, which is not easy to translate into 1d20.

A few notes :

Shield is useful against most weapons, but it's not really clear why it is sometimes useful and sometimes not (look ate the mace, for example).
If I multiply by 1.66 to get a score on 1d20, +1 to AC like in OD&D is OK.

Leather armour is allmost ineffective, Chain is really useful against 2 weapons and sometimes worse than without armour, plate is the only realy good armour, but it doesn't translate on a +6 on 1d120 like in OD&D.

[Torreny]

Some of the weapons like the flail are overestimated in their usefulness. I imagine the deal with the mace is due to the thinking that even with a shield to cover yourself from it, the weapon will break your arm with a good hit upon it, making the shield come off as less useful than it otherwise would seem.

[snorri]

Some choices are rather stranges. I'm currently doing a better table, which includes the efefcts of the bell curve. It will gives a different view on this issue and helps to compare with AD&D.

[snorri]

A better version now, abiut the shield only. The first table shows how a shield is effective in %, including the effects of the 2d6 bell curve. So it's the difference in percent between a unit with a shield and without a shield, with the same armour.



The second table is the same, on a d20 scale, rounding at the closest. A Funny thing is it shows a shield is really more effective in Chainmail when you wear a plate mail. So rsultats are realy stranges.