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Author Topic: Pure iron (100% iron) nor cast iron shouldn't be dominant metal for arms  (Read 18787 times)

Dwarfoloid

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(Edit) While the first post is still relevant, I recommend scrolling down to reply #8.

I hadn't really paid attention to it, as I saw a semi-official reply that bronze being better weapons/armor quality metal than iron was WAD, but looking through the raws it seems that the iron in the game is just that. Iron. Pure Iron. 100% iron with no carbon or residual metals.

While I must say that I'm not any kind of expert in metallurgy, skimming through wiki articles and some engineering related sites I found, it seems that while wrought iron is generally purer than the lowish carbon steel they used in middle ages, it could also have nearly the same material composition. The main difference, even if the materials were the same, seems to be that the impurities that make steel strong were concentrated in few spots in wrought iron, hence erratic properities.

What I find to be the problem here is that while Dwarves have little trouble spitting out loads of steel, Humans and especially Goblins have to do with something that is really sub par. Though it is partly the cause of penetration calculations not having enough variance and not enough damage being carried through the armor, you can quite easily find out with simple testing that steel utterly overpowers the current iron. Steel goes through iron every time and, according to testing carried out by Zagibu, steel deflects iron more than 90% of the time (this figure is for spears and swords atm).

Now, unrefined wrought iron is hardly the most ideal metal for arms and armor, we do have historical accounts of Celts having to streighten out their bent blades after heavy blows, but if DF is supposed to be set in around 14th-15th century thematically then Humans and Goblins only having access to pure iron is rather wierd, and I also feel it is unfair. Iron working cultures in that time period seem to have generally had know to how to make at least something akin to steel, or would have used wrought iron, which is as I pointed out, an iron alloy (but weaker than steel and again, erratic, hence the Polybius Celt reference). Oh and btw, if Gobbos use lots of steel in this version and I just haven't noticed it, now is the time to club me on the head.

So, based on the assumption that we want to retain a monopoly in manufacture of unobtainium űbermetal for dwarves I see two major ways of making iron less sucky.

First would be to give iron a great variance in performance from item quality. I don't know if quality for weapons does anything besides modifying monetary value in this version (ie. 0.31.03) but not matter if it does or doesn't, iron could be given a special scale that would make regular quality iron items worse than bronze of the same quality, about equal with bronze around superior quality and mastercrafts and artifacts near equal with steel mastercrafts and artifacts. For weapon and armour functions mainly.

This would abstractly represent skilled craftsmen/goblins/dwarves using techniques like forge welding to further improve what they have on hand (accurate forge welding would produce something akin to steel, by using the same materials dwarves in the game use for steel). Material properities of iron would need to be improved a bit overall, to make it bit more like wrought iron.

The second way would be actually creating a second type of steel, possibly a one that uses simpler reaction (so that it could serve dwarves as short term alternative on fluxless maps). Possibly, the common steel, the one that would replace current iron as standard material, could be based on low carbon steel, while the dwarf made steel could be based on mid carbon one. In real world though, the fact that mid carbon steel is harder and hence tends to break under stress easier, rather than bend, would have some possible negative effects even if it would otherwise penetrate better and resist better.

Possible naming conventions for the new metals (or alloys) could be soft iron, iron and steel (more intuitive, really) or iron, steel and some fresh name from the facinating dwarf language (ezarkel, ezarkelite or soldier-metal has a nice ring to it I think).

For comparison and possible reference, here are some tables for the steels I found, first low carbon, then medium:

http://www.matweb.com/search/DataSheet.aspx?MatGUID=034970339dd14349a8297d2c83134649

http://www.matweb.com/search/DataSheet.aspx?MatGUID=098700ed63b24b14bd3bfdbec937489f
« Last Edit: April 25, 2010, 01:49:21 pm by Dwarfoloid »
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Andeerz

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Re: Soft iron should not be dominant metal for arms
« Reply #1 on: April 23, 2010, 05:18:30 pm »

I appreciate the spirit of your suggestion, and I agree that metallurgy could use a bit of an overhaul in DF after material properties are sorted out.  However, I disagree with you.

I wish I had more time today, or I would write a better researched and well-written post.  But, basically, soft iron (IF you mean wrought iron) should be the dominant metal for arms and armor if we are wanting to emulate 14th c. European metallurgy.  Either that or bronze if resource distribution is different... but that's another matter entirely.  Swords were a bit of an exception, but a vast majority of metal armor and arms (like spear heads, maces, and stuff) were made of wrought iron, and only some of it was case hardened.  VERY rarely was actual temper-able steel ever made during this time period, and even then it was likely by accident.  I get this information from among other sources the first few chapters of a book called "The Knight and the Blast Furnace" which I wish I owned but was only able to take a glimpse of through some online-library that wanted me to pay to see the rest.

Wrought iron can be work-hardened which played to an advantage in armor, and case hardening, though I don't know if it was common in the 14th c. and earlier, was known and practiced in arms and armor.  As for weapons (and I really need to do more research on this cuz I don't know for 100% certain), I know that at least before the 14th century, there are many examples (and I can't say how many or if this was the most common or what) of sword blades made with a wrought iron core with steel (which was rare!) basically forge welded to the core to form the blade.  This steel was able to be tempered.  There are also examples of blades made from wrought iron that had enough carbon introduced into them through forging that the outer areas could be tempered and retain a durable edge.  Keep in mind that the iron in armor did not have generally have the same properties of the iron (and steely-iron) in the blades of swords since likely (I think) it was not economical to work them in the same way to introduce the steely properties.

Bronze is better than wrought iron for weapons and the like due to its hardness, but I believe it was surpassed in use by iron mainly due to iron's relative abundance (I could be wrong though...). 

What I would suggest doing to make metallurgy more realistic and reflect the 14th c. time-frame (and I believe in this case realism would make for a better game) in DF would be to emulate the following: 

1.  Realistic relative abundances of iron and other metals

2.  Variance of quality of ore (I can deal with this being abstracted out, I guess, but I think it should be implemented) from one vein or region to another: not all iron ores, even of the same type, are created equal!

3.  Better simulation of the bloomery and blast furnace (if we allow Chinese contemporary tech here, which I think we should) processes in how smelters work: i.e. have temp of furnace be affected by use of mechanisms to pump more air in, what kind of smelter it is, other engineering concerns maybe, etc...

4.  Better simulation of the forging process, especially if knowledge spread of techniques (like case hardening, carburization, decarburization, etc.) and technologies is ever implemented.

There are other things, probably, but I am running out of time.  I'm pretty sure the stuff I'm saying has been suggested before in the suggestions forum, but check out these two posts out from the modding forum that have similar concerns about metallurgy in the game:

http://www.bay12forums.com/smf/index.php?topic=33340.0
http://www.bay12forums.com/smf/index.php?topic=47914.msg1182154#msg1182154

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« Last Edit: April 23, 2010, 05:26:20 pm by Andeerz »
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Dwarfoloid

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Re: Soft iron should not be dominant metal for arms
« Reply #2 on: April 23, 2010, 05:40:58 pm »

In the context of my suggestion, I used soft iron to specifically mean elemental iron. Pure 100% iron with no carbon content or residual metals. This is what the game's material iron seems to take it's properities from (and do correct me if I'm wrong on this). I edited the OP and title to make this clearer.

My suggestion #1 was actually meant to use wrought iron as the universal material, and abstracting the varied craftsmenship methods of the time to skill level.

Suggestion #2 is based on the assumption that the material iron remains as it is and a new material is brought up to replace it's function as universal metal.
« Last Edit: April 23, 2010, 05:57:08 pm by Dwarfoloid »
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Andeerz

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Re: Pure iron (100% iron) should not be dominant metal for arms
« Reply #3 on: April 23, 2010, 06:13:17 pm »

Oh!  I see.  :P  Sorry for the misinterpretation.  I'm dumb!  Well, I guess I was in agreement with you after all!  I just homed in on the original title of the thread.  I won't do that again. 

I don't know if the game uses the properties of elemental iron... just in case, here's the properties of wrought iron on wikipedia!  I could have sworn this wasn't here the last time I checked.

http://en.wikipedia.org/wiki/Wrought_iron

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Dwarfoloid

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Re: Pure iron (100% iron) should not be dominant metal for arms
« Reply #4 on: April 23, 2010, 06:38:57 pm »

Looking at the wiki page, it seems quite clear that what is shown there is way different animal from this: http://www.matweb.com/search/DataSheet.aspx?MatGUID=654ca9c358264b5392d43315d8535b7d

Especially the tensile yield (wrought is much harder) and tensile breaking point (iron bends further without breaking, figures). ;D

And the notes in inorganic_metal roughly match the values shown for pure iron.
« Last Edit: April 23, 2010, 07:36:44 pm by Dwarfoloid »
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azrael4h

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Re: Pure iron (100% iron) should not be dominant metal for arms
« Reply #5 on: April 23, 2010, 10:55:02 pm »

Actually, according to some history books I have (not weapon specific, just general ancient history), about the time that Iron came into widespread use in weapons and armor, there was a shortage of tin. This of course was more regional than such a thing today, and of course use of iron, copper, or bronze for anything was highly dependent on materials availability, either by mining or trade. But in the majority of period accounts remaining, there seemed to be an impression that bronze casting of weapons and armor stopped because the bronze was no longer as available.

I'd like to see more metallurgy introduced (and would not be surprised if it wasn't already in the works as part of a overall materials overhaul), so I pretty much agree with the OP. The posts above pretty much match all I have read on the subject as well; which includes weapon-specific texts and a personal study of medieval weapons and their associated martial arts. I'd also like to see eventually the ability to make alloys of existing metals beyond what we have. Mixing a few bars of Iron and 1 strand of say <HFS> would create a new metal, once that was far better than Iron, but worse than <HFS>. 

It can probably already be done by a modder with enough time and inclination to do so. But I'm not much into digging through the RAWs so I'll leave that for someone else.
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Narmio

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Re: Pure iron (100% iron) should not be dominant metal for arms
« Reply #6 on: April 24, 2010, 02:06:11 am »

This is a very interesting article that anyone interested in this topic should read:

http://en.wikipedia.org/wiki/History_of_ferrous_metallurgy

Also of interest would be: 

http://en.wikipedia.org/wiki/Roman_metallurgy
http://en.wikipedia.org/wiki/Steel#History_of_steelmaking

The TL;DR:  The Iron Age was actually the Steel Age.  If we assume that DF is using pre-blast-furnace technology, AKA the manually operated or water-powered "bloomery", then all the iron in the game should actually be assumed to be wrought iron.  Which makes sense, because "wrought iron" just means "worked iron", and another name for it is "bar iron".  However, weapons and armour were not made of wrought iron but of carbon steel as early as the 4th century BC on the Iberian peninsula and China, with examples of ancient steel from East Africa dating back to 1400BC.  Steel, or at least a Hebrew word thought to refer to steel, is mentioned in the Bible.  In Sri Lanka steel was made using an awesome thing called a "wind furnace", which was set into the far side of a sand dune and the monsoon winds were directed down tubes straight into the forge, creating the temperatures needed to melt the iron (which did not happen in the usual bloomery process) and mix it with charcoal. 

So, in game.  I don't believe we need to rename 'iron' or introduce wrought iron, it can just be assumed. It should be possible but not smart to make weapons and armour from iron, but it really should be assumed that anyone with iron-making technology should have the ability to produce steel.  Not high quality steel, not large amounts of steel, but some.  Whether this means that humans and goblins should be thrown back into the Bronze age, or whether they should be permitted some few steel items on elites, or whether some measure of steel quality should be introduced*, I don't know.  But the game should certainly not encourage wrought-iron arms and armour.

* This is actually partly modelled already by item quality - the smith forging a sword was almost as important in the quality and characteristics of the steel as the furnace operator who smelted it.  I would be perfectly happy to abstract all of this knowledge about carbonisation, quench-hardening, tempering, forge-folding etc and say that it's part of the difference between a plain quality steel sword and a dwarven masterworked one.
« Last Edit: April 24, 2010, 10:35:45 pm by Narmio »
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Pilsu

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Re: Pure iron (100% iron) should not be dominant metal for arms
« Reply #7 on: April 24, 2010, 08:35:19 am »

Material quality affecting the performance of the finished product is still ways off. The material quality of cloth products just adds a flat sum to the price of the end product, it'll take a long time before that particular experiment extends to the point material quality becomes critical to the performance of the items made.

In the mean time, if you want Toady to update the raws values for iron to match wrought iron, provide the data and sources used.

Dwarfoloid

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Re: Soft iron should not be dominant metal for arms
« Reply #8 on: April 25, 2010, 01:08:12 pm »

(and do correct me if I'm wrong on this)

No you noob, you are looking at the wrong place! Check material_template_defaults, it tells that the scale is KPa!

Well, now that I have corrected myself, I have some "new" findings. As seen in the beforementioned file, the scale in the raws is KPa and most of the figures for yield and fracture are taken from 'tensile strength, yield' and 'tensile strength, ultimate' while the elacticity seems to follow a rather inconsistant fashion, not entirely related to real world values.

I also found out that Toady got many of those figures (brass, steel, iron, copper, spider silk...) from wiki page for tensile strength. And so I also found what iron Toady used in the game. It's not pure iron that the elasticity notes led me to belive, but cast iron. Ie. what we call pig iron in the game (stiff, but brittle, high carbon iron). Here is a MatWeb link for what appears roughly similar type of cast iron:

http://www.matweb.com/search/DataSheet.aspx?MatGUID=ec56a89f37f74e2f867a64b0f87f1e9d

In any case, that is wrong as well, if we are modelling DF universe after Europe where wrought iron was mainstay and cast iron appeared on any notable scale rather late. You can read on these developments, and on how the european bloomery process produced wrought iron from the wiki article "History of Ferrous Metallurgy", to which Narmio posted a link two posts up. I'll repost it here in any case.

http://en.wikipedia.org/wiki/History_of_ferrous_metallurgy

Here are some links for wrought iron properities. The first one is to the wiki article, ofc, which also lists some properities. The second one provides us insight on 4 different types of unnamed wrought iron (multiply the values by 13790 to get KPa values). Sadly it doesn't list source, but the figures seem consistant with wiki figures (also, looking at the types of alloys listed, it might be from late 19th or early 20th century book). The last link is a special one. It's the site of what claims to be the sole provider of authentic wrought iron. What is really interesting is that they provide charcoal iron, the type of iron used in middle age Europe. While they do not list any material properities on their site, they could be contacted directly to provide them.

http://en.wikipedia.org/wiki/Wrought_iron
http://www.eformulae.com/engineering/tensile.php
http://www.realwroughtiron.com/

Obviously, modelling the game's iron with pretty much any of these values would make it superior to bronze. If this is not desired behaviour, here are some MatWeb links for tin bronzes (but read more on this below).

http://www.matweb.com/search/DataSheet.aspx?MatGUID=313a16ab4bd54855b7ad8b86282f37a2
http://www.matweb.com/search/DataSheet.aspx?MatGUID=740dedaf9a6247d5ade1e2d08a2d52ab
http://www.matweb.com/search/DataSheet.aspx?MatGUID=e775c32433c342888766a554462127f5

Additionally, this wiki article has some information on tin content of ancient bronzes.

http://en.wikipedia.org/wiki/Bronze_age_sword

Next up, the brass in the game is curiously strong (second to steel in normal metals), so I though I'd provide alternative properities to it. Ofc, as brass is not a weapons grade metal in the game, this change would only be for raw flavor and consistance and for arena and the few odd artifacts. To be specific, this is what appears to be soft 'Orihalcum' type brass, a type used in Roman world (claimed by the MatWeb description, confirmed by wiki).

http://www.matweb.com/search/DataSheet.aspx?MatGUID=857e1e3dd0b84b09895aaaecaa1a0344

Lastly, the steel in the game is really strong, but perhaps I'll leave that to later time.

Overall, I'd like to point out that sites will quite naturally be listing properities of modern alloys, especially sites like MatWeb. So to get cruder more medieval values, taking low values or low averages is better practise than taking averages or high values.

On the issue of Bronze vs. Iron: Lots of people seem to use the claims on wiki that state that iron did not replace bronze because it was better as a proof that this was the case overall. However, I'd like to bring some context to this. In the past, it was a common "myth" to attribute some military successes of late bronze age to use of iron. Mainly those of Hittites. You can see this at play, for example, in the 1954 Hollywood Epic 'The Egyptian' where Sinuhe brings a "sword of new black metal" from Hittites back to Egypt as a warning and uses it to cut through bronze sword to provide example. So when historians are saying that iron did not replace bronze because it was better, they mean in context that precence of ironworking should not be used to explain military successes in late bronze age.

Also worth mention is that bronze age lasted for very short times in places where ironworking and bronzeworking appeared in short span of time. Notably Japan.

Material quality affecting the performance of the finished product is still ways off. The material quality of cloth products just adds a flat sum to the price of the end product, it'll take a long time before that particular experiment extends to the point material quality becomes critical to the performance of the items made.

Well, it would require balancing work and would need the weapon grade metals to be tested individually. But there is already a code for quality affecting weapons from 40d, afaik. If Toady provided ability to mod quality with raws and included ability to specify quality in arena, this could be at least partly done with fan testing.
« Last Edit: May 04, 2010, 05:22:55 pm by Dwarfoloid »
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Warlord255

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Obviously, modelling the game's iron with pretty much any of these values would make it superior to bronze.

The question, then, is this; how much better? I'm fine with iron being a strong metal, especially if the current "tech-level" for goblins and humans is to stay in place.
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Dwarfoloid

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At the moment the most important variables seem to be tensile yield and ultimate tensile strength (or breaking point). The latter is called fracture in game. The values specifically called "tensile" in the raws seem to not be in use, but tensile data is used for shear data atm (and shear data is used for edged combat calculaions). Actual shear values seem to be lower than tensile values irl, but these values should be found for all weapon grade metals before that change can be made.

Bronze is currently:

Yield: 137000
Fracture: 241000

Iron is currently like this. It seems to be the irl figure for ASTM A-48 grade 20 low grade grey cast iron:

Y: 130000
F: 200000

Grade 60 (highest I found) would have tensile strength of at least 430000.

Link for that: http://www.sackinmetals.com/properties_of_grey_cast_iron.htm

And what the heck, steel is, for comparison (this is, actually, cold rolled stainless steel, so yeah):

Y: 520000
F: 860000

From the links above for wrought iron, first with wiki:

Y: 159000–221000 (190000)
F: 234000–372000 (303000)

And the 4 specific wrought irons, maching pairs directly above and below eachother (rounded a bit):

Y: 205000, 235000, 230000, 155000
F: 300000, 340000, 345000, 310000

Pure iron would be, for interest:

Y: 50000
F: 400000

And here are the MatWeb bronzes:

Y: 205000, 150000, 172000, 207000
F: 380000, 305000, 241000, 241000

And the brass I suggested is:

Y: 83000
F: 290000

This would equate to rather soft, copper-like brass. Harder brasses are found on MatWeb, but I have absolutely no idea if such properities could have been practically achieved in medieval period.

The bolded ones are the ones I would suggest for use. Especially the last wrought iron has a really long margin between yield and break, so would equate to rather low carbon iron, perhaps the type that would best represent medieval charcoal iron type wrought iron. On the other hand, many wrought iron bars would have presumably turned out stiffer than the rest, and I'm sure medievals (or Goblins and Humans) would have recognized their worth for weapons and armor manufacture, hence the optional pick (things like pattern welding had been used in early medieval period afterall). The bronze I chose has lower margin than either of the irons, to match the claims that bronze should be more brittle. The second bronze values would be my second choise, especially as the type maches the tin content from the (unsourced) claim on the wiki article for bronze age sword.

This wiki article may contain interesting information about early iron swords: http://en.wikipedia.org/wiki/Celtic_sword. Among other things, it contains some musings about the account from Polybius I mentioned in my first post.

Additionally the elasticity figures could use some work. Iron, even pure iron, has much better values across the board irl than the copper alloys. However I'm not sure what the game is currently equating as "good". For example, iron is pretty low now, lower than gold and bronze, steel is quite a bit higher than them while stuff like skin are really high. Irl, iron and steel would be the most rigid of these. If high is good for metals, the values for iron should be increased, no matter what tensile values are used. If low is good, then steel is too high.

Lastly, here are two values for crucible steel from the same link that the 4 wrought irons came from, brought up because the dwarven method of steelmaking vaguely resembles some methods of making crucible steel (though if the values from the link are from a late Victorian period book as I suspected, UK or American, these values would be for the English type crucible steel, not for "fake" damascus steel I had in mind).

Y: 430000, 340000
F: 720000, 650000
« Last Edit: May 06, 2010, 12:04:03 pm by Dwarfoloid »
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Dwarfoloid

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Allright, I have been skimming through threads in Sword Forum International, a forum I frequented 5-7 years back and remembered as a place that both professional and dabbling bladsmiths and academicans frequented.

Here are some thread linky's from there and some other sites:

On manufacture of bronze swords: http://www.swordforum.com/forums/showthread.php?t=89427

A site of a bronzeworking swordsmith: http://www.bronze-age-craft.com/swords_for_sale.htm

The links above contain some musings about manufacturing process and tin contents, as well as lead contents.

Here are some articles about iron age and early medieval ironwork, sadly, they only list material makups and Vickers hardness (HV).

Bit on patternwelding: http://www.swordforum.com/forums/showthread.php?t=97948

Some Properities of period swords: http://www.swordforum.com/forums/showthread.php?t=75531

Here is a longish article about Merovingian (early Frankish) metalwork: http://www.tms.org/pubs/journals/jom/0508/ehrenreich-0508.html

Among highlights, it seems possible that late iron age and medieval smiths were capable of picking their ferrous materials depending their phosphorus content, which seems to have similarily beneficial properities as carbon when the product is not quench hardened.

Here is a yet another MatWeb link, this time to lead bronze, which seems to very roughly match the composition that the bronzeworking smith described on his site.

http://www.matweb.com/search/DataSheet.aspx?MatGUID=a3eac50be4814666bf2f318def6cbf9b

I'd might mention at this point, that while the game doesn't have measure for hardness values per se, these could be represented with the edge value. Hardness would be very beneficial for holding a good edge, especially for retaining the edge in actual combat.

I'm more and more coming to the opinion that the current notion in game that bronze is superior to iron is false. At least by the middle ages.

BTW, any comments would be welcome. I have the feeling that I'm keeping this thread up just for my own pleasure. Even just commenting if this kind of ad-hoc research is appriciated at all would be welcome.
« Last Edit: April 26, 2010, 05:56:54 pm by Dwarfoloid »
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Footkerchief

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I've been reading a lot of your links, so yeah, count me as interested.
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Mephansteras

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I'm also interested.
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Narmio

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This is very cool stuff, I'm definitely reading it.  I was wondering if you've had a chance to look at the impact yield and impact fracture variables?  They're the blunt combat ones, and are currently all placeholders fromw hat I can see.  From some experimentation I did they're the source of blunt weapons' uselessness right now.  Well, that and the lack of internal bleeding.  If you leave fracture high but drop yield, every strike is a serious bruise.  If you drop both, every strike breaks bones.  So there's some complex interactions going on.
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