RE: (TFT) Guns and Armour Penetration.

["Ty Beard" <tbeard@tyler.net>]

> -----Original Message-----
> From: tft-owner@brainiac.com [mailto:tft-owner@brainiac.com]On Behalf Of
> Charles Gadda


> how important armour is. There are many, many other such
> anecdotes, which is
> why I really do advise getting this book, if you can. Its just too much to
> summarise in an e-mail. If you have a real problem, give me your mailing
> address, and I'll let you borrow my copy (please return it,
> though - I over
> spent as it was... :-)

A gracious offer and I appreciate it, but I'll probably just run it down
myself. It sounds like something that needs to be in my library.

> Certainly I think it quite possible for a breastplate to stop a musket
> round. The late Mediaeval breastplate, at least the better ones,
> could be of
> surprisingly good quality steel - easily matching the steel used
> in swords,
> and was often heat treated. Granted, it was *streaky* steel, of varying C
> contents (0.2-0.8%), usually with slag inclusions. But, again, the better
> stuff minimised this problem. Ballistically, it had very good sloping and
> could be quite difficult to plant a solid, non-glancing hit on. The
> thickness could be up to 1/8" in some places, which is an awful
> lot of steel
> to poke through, even for a musket. Sources: Longbow, by Robert

<snip>

I may well have overestimated the penetration of primitive guns...

> I was aware that spherical rounds lost a lot of V with range - any stats?
> Esp. comparing with arrows or bolts? I've always wondered how to
> model loss of power with range, myself.


Unfortunately not. 	My penetration resarch has been confined to modern tank
gun penetrators (which lose surprisingly little KE at typical engagement
ranges).

> 1. Recognise your point regarding statistics, but there is one possible
> problem here, namely, what are the actual period casualty
> statistics? Maybe
> it is funny, but, what if a breastplate really was that
> effective, or maybe
> even better? Unfortunately, the only way to find out is to take 200 less
> than wise people, issue half breastplates and the other half T-shirts with
> bulls eye's painted on them, and plug each with a Brown Bess and
> record the
> results. Not sure how you'd get a permit to do that... or how expensive it
> would be...

True. I just wondered if there were any accounts of guns being ineffective
against armored targets, comparable to the numerous accounts we have of
longbows doing the same (Froissart [sp?] for instance).

> 2. Less than 30m- distance would certainly maximise K. E. As to historical
> evidence, there is some, but of course the details (muzzle V, armour
> quality, etc.) are often lacking. I do not think crossbow penetration is
> solely K.E. As a thought experiment, I plugged some numbers into the
> penetration formula listed in Longbow, and came up with the same
> penetrative
> ability as a musket, when one factors in the X-section area (I
> assumed 1/4"
> bodkin for the crossbow and a .75" D ball for the musket. The upshot was
> that the bodkin point did 1/7th of the work of the musket ball. Granted
> these are poor figures, but as a ROM it is quite illuminating) I admit,
> though, that factoring the point of a crossbow bolt/ arrow is
> difficult; but
> one has to figure that, at initial contact, whatever K. E. the bolt/arrow
> has is going to be focused on an area around 0.001" square. That
> considerably magnifies the effect of said bolt/arrow. I would
> expect that a
> lead musket ball will deform considerably, possibly mushrooming
> well beyond
> its initial diameter, but I have no way of modelling that (yet - but that
> may well be from a lack of looking on MY part...)

There are severe problems with a "KE per square cm of cross-section"
analysis. As Frank Chadwick pointed out in Fire Fusion and Steel, the German
20mm has a higher KE/cm^2 figure than the 75 long (IIRC)! Kinetic energy
appears to be the most relevant measure of penetration with modern firearms,
though penetrator design is critical as well (long, thin metal penetrators
seem particularly > effective). I have no idea if this holds true for small
arms, but it is very true for large penetrators.

> As for the change from
> swords and pikes to muskets, a couple of points.
<snip>

Points taken; I'll have to review my sources.

> One problem with K.E. theory. Part of my reluctance is an article
> in the Nov
> '96 issue of Military Illustrated, which dealt with the infantry anti tank
> rifles (Boyes, M1918 Mauser, Solothurn, etc.) While most were difficult to
> compare, I came across a couple that were close enough to make a
> meaningful
> comparison. This was the 13x94R steel core AP (fired from a Mauser M1918)
> and a very modern 7.62x51 NATO round, manufactured by FFV in Sweden. THe
> former round is 800 gr, with a muzzle V. of 2525 fps. The latter
> is tungsten
> cored, 130 gr, and a muzzle V. of 3120 fps. The 13x94R has an energy of
> 11396 ft-lbs while the FFV round is only 2960 ft-lbs. Yet both are capable
> of penetrating 15mm of armor plate at 300 meters! Granted, the quality of
> the armor plate is not specified, but one would reason that any
> differences
> would favour the WWI vintage 13x94R, rather than the ultra modern
> FFV round.
> This is a major reason why I don't consider K.E. to be all
> important.

Just a cautionary note -- in evaluating hundreds of modern weapons systems,
I found most "hard" penetration data to be useless because the information
was incomplete, leaving out slope, range, and specific ammo types.

> Also, the point about hit points is spot on - it is a weakness. It can be
> overcome, but it involves a lot of overhaul. I have some ideas,
> mostly along
> the lines of allowing high penetration weapons to use one die, while other
> weapons use multiple dice, and have armour (depending on type)
> subtract from
> *each* die of damage the weapon does. For example, say mail stops
> 2 hits/per
> die. A short sword with 2-1 dice will do 2d-5 in this case (ave
> dam 2) while
> a small axe at 1d+2 will do 1 die (ave damage 3.5). This is not the best
> example; I had worked it out a bit more, but it kinda illustrates
> the point.

I used a similar system in an early high tech supplement for TFT, posted at
my website. Modern armor subtracted X from each die of damage done by guns
and X from the total damage done by melee weapons.

Even more aggravating is that a non-hit point system will be very
unsatisfying to players IMHO. Hit points serve one critical function -- they
tell you where you are. A non-hp system won't do that...

--Ty
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