Would it be unbalancing to have this kind of spiked warhammer in Pathfinder?

Question

The weapons I, as a GM, would like to include are warhammers (both a one and a two handed weapon) in the spike and flat, or often crenelated, style that real 14th century medieval hammers used, something that would be build a bit like this one:

That stats would be as follows:

One-handed 12 gp Dmg(S)1d6 Dmg(M)1d8 Crit x3 Weight 5lbs Type B or P
Two-handed 25 gp Dmg(S)1d10 Dmg(M)1d12 Crit x3 Weight 10lbs Type B or P

The one-handed version to have a +1 bonus to Sunder Medium and Heavy Armour, and the two-handed version a +2.

Given the vast array of weapons that are part of the existing Pathfinder arsenal I'm concerned that there is something unbalancing about the proposed weapons that I'm missing that has prevented their inclusion. So my question is, hopefully, simple; would these weapons as proposed be unbalancing to the game?

Note I'm not married to the stats exactly as written if a minor tweak makes them more workable.

Answer 1

The balance for these weapons seem reasonable (except they should cost 23 gp and 40 gp if you want them to be martial weapons) w.r.t. custom weapon design rules.

You can find Pathfinder's weapon creation rules here: Creating New Weapons. It comes from the Weapon Master's Handbook. (GM approval still required of course.)

You can figure out the number of design points you have to work with based on if it is martial (5 DP) or exotic (6 DP).

All new weapons begin with the following base statistics: Dmg (M) 1d3; Critical ×2; Type any one (B, P, S); Price 1 gp × the weapon’s base DP.

1-h, damage=1d8, critx3, B or P, sunder+1

• Improved Critical Multiplier (3 DP)
• Improved Damage (3 x 1 DP) - 3 steps to go from 1d3 to 1d8
• Additional Damage Type (1 DP)
• Weapon Feature (1 DP) - seems to fit for your sunder property (though technically not on the list)

These features would cost 8 DP. A 1-handed martial weapon has a base of 7 DP (7 gp)and a 1-handed exotic weapon has a base of 8 DP (8 gp).

You can use Additional Design Points to get an extra DP for 15 gp more. So a martial version would cost 23 gp and an exotic version would cost 8 gp.

2-h, damage=1d12, critx3, B or P, sunder+2

• Improved Critical Multiplier (3 DP)
• Improved Damage (5 x 1 DP) - 5 steps to go from 1d3 to 1d12
• Additional Damage Type (1 DP)
• Weapon Feature (1 DP) - seems to fit for your sunder property (though technically not on the list)

These features would cost 10 DP. A 2-handed martial weapon has a base of 8 DP (8 gp)and a 2-handed exotic weapon has a base of 9 DP (9 gp).

You can use Additional Design Points to get an extra DP for 15 gp more. So a martial version would cost 40 gp and an exotic version would cost 25 gp.

Answer 2

Take a Bec de Corbin as your base

A Bec de Corbin is one of Pathfinder weapons that is influenced by real-world weapons and not stuck on fantasy, like the warhammer (which is depicted on pathfinder art both with spikes and not, by the way).

It is a two-handed weapon, so it deals 1d10 damage rather than 1d8 from the warhammer, so you could merely scale it's size down to one-handed weapon and keep the 1d8 as base damage for the weapon. The long handle turns it into a reach weapon, granting it both reach and brace (so it can be readied against a charge). The weapon already does either bludgeoning or piercing damage, which seems to be what you want.

Finally, you also keep the sunder property against armor, which is the historical point of that spike on the back.

Benefit: You gain a +2 bonus to your CMB to sunder medium or heavy armor with a bec de corbin.