Home » FULL CONTROL GAMES » #JAFDEV » Ammo Types
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| Re: Ammo Types[message #323184]
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Thu, 25 July 2013 00:09  
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 Akodo Deathseeker |
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Messages:104
Registered:March 2001
Location: St Paul, MN |
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Reserved for discussing expanding aka 'hollow point' ammunition
Expanding ammunition.
A bullet can punch clean through it's target or it can find some way to affect more area inside it's target.
The basic way of doing this is expanding and/or fragmenting. The flip side of this is that extreme penetration or fragmentation results in insufficient penetration. You leave a nasty looking surface wound but the target is still up and fighting.
A little bit of bullet basics here. Bullets started out as solid lead. As propellant quality increased higher velocities were achieved...but this lead to some problems with lead! Lead bullets were actually having their bases melted by improved gunpowder which played havoc with accuracy. Even when not being literally melted, higher velocities were causing a ton of lead fowling in the rifle barrel. Finally, lead bullets were literally disintegrating when they left the barrel at certain speeds.
The solution was to put a metal jacket on. This worked great for accuracy and cleanliness but the bullets didn't seem to have the same 'down range effect' on targets. Part of this is that many of the earliest 'modern' guns weren't achieving high enough velocity to affect the target through hydrostatic shock.
The easiest way to deal with this was to expose some lead on the nose of the bullet. Now the base didn't melt, the rifle wasn't excessively fowled, the bullet didn't break apart in flight, and the tip expanded somewhat, giving increased lethality. Exposed lead and the hollowed lead (actually first done to simply lighten the bullet to allow higher velocities) was discovered by hunters, but made famous by the Dum Dum arsenal in India.
There is a sliding scale of expansion. Exposed lead soft nose expands some, a hollow point expands more, a hollow point with 'petals' expands more (and the petals after opening often sheer off and do their own damage) and finally rounds designed to fragment as soon as they hit the target expand the most. But as mentioned before extreme expansion means lack of penetration.
The same features that make the bullet expand well also make the bullet less effective vs barriers and ballistic armor.
This game need not get bogged down on the details. I suggest two suffexes to be used on ammunition in JAF
HP - hollow point
SP - soft point
HP would be applied to pistol ammo only. It would increase damage by 25% on unarmed targets and decrease damage by 25% on armored targets.
SP would be applied to rifle ammo only. It would increase damage by 15% on unarmed targets and lightly armored targets but vs heavy armored targets would decrease damage by 10%
The percentages are not exact of course, it depends on the actual figures, especially in how different types of arms relate to each-other. And how much armor is considered 'heavy armor' would also be determined by exactly how that metric ended up being spelled out.
[Updated on: Thu, 25 July 2013 00:54] by Moderator Report message to a moderator
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Sergeant
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| Re: Ammo Types[message #323187]
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Thu, 25 July 2013 00:10
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| Akodo Deathseeker |
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Messages:104
Registered:March 2001
Location: St Paul, MN |
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reserved for discussing how flawed the Depleted Uranium ammo as currently spelled out is
Depleted Uranium is a common material for military use. However, there needs to be some basic ballistic understanding.
There is actually a lot of aerodynamic theory that goes into ballistics.
Let me diverge into shotgun shells for a minute.
As I am sure you know shotgun shells fire a bunch of little pellets. You can buy all sorts of different pellet sizes.
generally, small pellets like 8s are for quail sized birds, 4 is for pheasant and duck, 2 and bb are for high flying geese.
Generally a shotgun shell has a set amount of gunpowder in it and then a 'payload' of lead generally measured in oz. So for instance you could have a shell that is described as firing 1 oz of 8 shot or 1 oz of 4 shot. In both cases 1 oz of lead is being shot...but in one case it is broken up into 410 pellets and in the other it is broken up into 135 pellets. Because the weight being launched, at least initially the pellets regardless of size leave the barrel at the same speed.
Lead shot size diameter in inches, (expressed as a decimal), multiplied by 2200* gives the maximum potential distance in yards. (To convert SAMMI voluntary numerical shot sizes to decimal, subtract shot size from 17 then move decimal two places to the left).
So, an oz of lead broken up into 410 pellets (8 shot) goes 198 yards. An oz of lead broken up into 135 pellets (4 shot) goes 286 yards. (Note this is total travel distance, it may not have enough energy to penetrate skin at this distance)
Why is that going on? Because more surface area of the 1 oz was exposed to the air.
Now, for quite some time to hunt waterfowl there was a rule that you had to use 'non-toxic' shot. The fear was that too much lead was getting into the food chain. (This turned out to be based on junk science, but the law still stands.) The solution was to offer shot in steel pellets.
So shotgun shells would still fire the same total weight...generally 1 oz. However hunters soon found that the steel shot wasn't very effective. This was because as it was less dense 1 oz of the same weight. 8 shot had 686 pellets of steel vs the 410 of lead, giving that 1 oz a lot more surface area. The rule of thumb was for hunters to pick up steel shot that was 2 to 3 sizes bigger than what they were using before to get similar results. Still, it just wasn't the same. Plus, the harder pellets could damage the barrel.
Lately, shotgun makers have turned to mixtures of either Bismuth or Tungsten in an effort to find something that is just as dense as lead, meaning less surface area.
AND THIS BRINGS US TO DEPLETED URANIUM.
The reason behind depleted uranium bullets is it is more dense than lead. (at room temperature, water = 1, steel = 7.8, lead = 11.3, Uranium = 19.1)
Note that if the two projectiles weight the same, standing in front of the muzzle both will deliver the same energy on impact. The more dense DU will bleed less velocity over it's flight path. It only really comes into play when a projectile is traveling far enough that it looses about half it's energy, with DU it would retain about 2/3s of it's energy (and retain more speed so less drop due to gravity). As suggested by the shot size formula using fixed weight, if weight itself becomes the variable, you get more 'bang for your buck' when firing heavier and heavier projectiles.
This means DU only really shows a reasonable gain when fired in large bore weapons. It started out being used in the 30mm autocannon of the A-10, then the 25mm autocannon of the Bradley fighting vehicle, and now also in 20mm autocannons of the A1 Cobra.
(In tank shells, DU is used for it's pyrophoric effect more than for it's density, for defeating certain kinds of armor, not something applicable to the other shells. See the discussion on the RPG for more info)
This is not a technology that 'scales down' to be used in personal weapons. Heck, there isn't enough gain in the 50 BMG or the 12.7mm range for it to be used.
If Jagged Alliance wants a 'super-ammo' that does more damage than conventional...this is not it.
*Note that formula is not exact because there are some variances in the velocity of pellets launched. This is assuming a velocity of 1275 fps. 1250 is a more average speed. I suspect a little bit of 'safety factor' was present in choosing the higher velocity.
[Updated on: Sun, 11 August 2013 08:18] by Moderator Report message to a moderator
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Sergeant
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| Re: Ammo Types[message #323189]
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Thu, 25 July 2013 00:11
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| Akodo Deathseeker |
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Messages:104
Registered:March 2001
Location: St Paul, MN |
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Final reservation, alternate suggestion, 'overpressure ammunition'
So, it appears to me that the designers wanted a 'super-ammo' that did a lot more damage but wore the gun much faster. They chose DU, but as shown above DU really doesn't do this, especially not in calibers much below 20mm.
So here is my alternate suggestion:
Every cartridge has a 'working pressure'...this is the maximum amount of pressure that can be built up inside the chamber while the gun is firing. There are different types of gun powders with different size pellets that give different burn characteristics. Even with the same gunpowder, changing the weight of the projectile increases the pressure that will build up inside the gun.
This pressure is also what can blow apart a gun, possibly taking the shooter's fingers with it, or spraying their face with shards of the gun.
When you see designations like +P that means the ammo is designed to fire at slightly higher pressure than normal. The reason is because it gives more power...the bullet flies out the end faster. The risk is it could damage the gun. This +P ammo is really only seen in ammo that was designed very long ago (both the 45 acp and the 9mm are designs over 100 years old) who were matched to the weaker steel back then, and now stronger steel is being used. Most of the time this is a 10% increase in operating pressure.
Now, guns are over-engineered. A gun must be able to withstand a 'proof cartridge' that is designed to create 135-150% of the normal operating pressure would be.
In theory, if you load your own ammo you can come up with mixes and formulas that surpass the normal. (Actually, this is a VERY common practice...people just vary in how far they will push it). Generally the technique is to examine the spent cases to determine if you've moved into dangerously high territory. These handloaders of course do this to wring more power out of their firearms.
I think it would be entirely appropriate to introduce 'over-pressure' ammo as a kind of super-ammo into JA:F. It will wear the gun faster than normal (or more accurately, batter it heavier, causing things to shake loose) so that again matches the 'balancing act' JA:F designers seemed to be indicating with the DU ammo. The icing on the cake would be if every time a merc fired using over-pressure ammo there was a very small chance of the gun blowing up in his hands and doing some damage to him.
I'd put it at a roughly 0.1% chance. This means you'd see one about every 1000 rounds fired. 3 or 4 mercs in a battle would collectively use about 200 rounds I suspect, so you'd see this kind of failure maybe once every 5 or so battles. Obviously if a gun is blowing up every 100 rounds or so that's just too great a risk and I don't think players would use it often but 1 every 1000, that to me spells a wonderfully fun 'oh crap! I can't believe that happened!' moment.
[Updated on: Sun, 11 August 2013 08:36] by Moderator Report message to a moderator
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Sergeant
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| Re: Ammo Types[message #323196]
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Thu, 25 July 2013 00:57
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| Akodo Deathseeker |
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Messages:104
Registered:March 2001
Location: St Paul, MN |
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I realize that a kickstarter post isn't going to be the most informative. Still, I think it is important from the start to use the right term. Additionally, without clarifying 'bullet' some of the posts that come after may not be clear.
note that while the kickstarter update didn't specifically mention AP and HP ammo, I went with the assumption it was a general post not a highly detailed and full explanation. Still, there was enough detail in some aspects of the summary to give me serious pause.
Also, while the information is readily available, often understanding of exactly what it means and how far it can be applied is missing. For example the explanation of 'stealth' ammo is SPOT ON but just for a very limited group of cartridges.
[Updated on: Thu, 25 July 2013 00:59] by Moderator Report message to a moderator
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Sergeant
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| Re: Ammo Types[message #323217]
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Thu, 25 July 2013 13:06
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| Mauser |
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Messages:756
Registered:August 2006
Location: Bavaria - Germany |
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Yeah, take it easy Akodo, i am sure FC won't leave it at that, knowing very well that the fan community, especially here at BP, will rip them a new one if they don't adhere to certain basic conventions and standards expected for proper gunporn.
Also, JA:F is still in early pre-production and nothing is cast in stone yet.
We have some massive threads here regarding all aspects of weapon technology and ammunition, that will tell the FC dudes everything they need to know and look out for.
Also they should be quite aware, that nobody here will accept anything less complete and elaborate than the original JA2 guns and ammo system and instead expects them to improve upon it, even though the perfection and scope of 1.13 will be left to the modders to implement.
But agreed, FC should watch out what information they communicate publicly regarding these things, in order to not make them look like amateurs. They should know, that their fans and supporters hold them to higher standards.
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First Sergeant
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| Re: Ammo Types[message #323866]
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Sun, 11 August 2013 06:48
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| Akodo Deathseeker |
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Messages:104
Registered:March 2001
Location: St Paul, MN |
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Okay, maybe designers know enough not to make subsonic everything. I hope so, but I think there is at least a significant chance that they would apply it to everything unless told otherwise by someone who knows guns. Note, I don't think this is me, or anyone on this forum. I mean it could be, but I really hope that they just in general have someone they can call up and ask questions to about guns.
As far as rubber and DU, these would be an even more limited item. Yes, I suppose there could be a scenario or special mission where you have to capture someone or something where having rubber slugs in your shotgun is going to be a boon. However, in my general experience game designers don't usually bring up 'one off' stuff in their game development blogs/notes/updates, they tend to give info that holds for the majority of the game.
Final note, this forum is always quite buggy for me. I often have to shut down my modem/router and then start it back up again after a half minute wait. I don't have to do this for other forums. Anyone else have this problem?
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Sergeant
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