Small Arms Ammunition

[monbvol]

I'll confess to being a little lazy there... when I say "plastic", I really mean "composite".  The casings can handle the increased pressure and heat so the bolt and barrel don't have to.  The barrel just has to be big enough to pass the bullet.  It really is revolutionary technology application (since the tech has actually been around a while).

Sure it can absorb some of the pressure but not all of it, that is what is propelling the bullet down the barrel after all.

Looks like the error was confined to an early version of my combining of my infantry weapons to TW scale and my infantry armor kits to TW scale conversion sheets.

For the stand alone weapons sheet first post in this thread should have something usable.

If that fails for some reason I have an in progress final product towards the end of this thread that I know works but is full of my full conversion AU stuff.

[Daryk]

Riflemech:

1) It depends on what you're playing.  Are you playing AToW or TW?

2) Here's how heat transfer works (I am, in fact, a physicist): good conductors (like brass) transfer heat quickly.  Quickly enough to transfer it to the block, and the outside of the casing (meaning they both feel hot after a shot).  Poor conductors transfer heat slowly, meaning they absorb more heat into their mass and only slowly radiate it outward.  This means a plastic (really, composite) casing will absorb more heat into itself, and only slowly transfer it to its outer surface, and thus the block.  This is why both the block and outside of the casings feel cool to the touch immediately after firing in the video.  Am I making sense yet?

3) I haven't read anything about 5.56 composite rounds, so I'm afraid I can't answer that question definitively, but I believe most current 5.56 rifles have sufficient overengineering to be able to fire at least SOME rounds before requiring replacement.

4) Link as requested: https://bg.battletech.com/forums/fan-designs-rules/fixing-the-atow-companion-conversion-to-tw-for-mech-weapons/msg1709504/#msg1709504

5) At least one point got through!

6) No, not right.  As I explained above, the composite casing absorbs more heat into its mass vice conducting it to its exterior surface, and thus the gun.  When the casing is ejected, it takes all that absorbed heat with it, and that is MORE than the brass carries with it.

7) That one's monbvol's, and he already answered it...

[RifleMech]

Looks like the error was confined to an early version of my combining of my infantry weapons to TW scale and my infantry armor kits to TW scale conversion sheets.

Found the link. Yay! It's not what I was looking for though. I was looking for something that says how much damage per weapon is done per round to BAR armor and in TW.

Riflemech:

1) It depends on what you're playing.  Are you playing AToW or TW?

That's just it. There shouldn't be one of the other as you should be able to go back and forth. Right now an Auto-Rifle in AToW is far more powerful than one in TW. And that's not including the fact that AToW turns are twice as fast.

2) Here's how heat transfer works (I am, in fact, a physicist): good conductors (like brass) transfer heat quickly.  Quickly enough to transfer it to the block, and the outside of the casing (meaning they both feel hot after a shot).  Poor conductors transfer heat slowly, meaning they absorb more heat into their mass and only slowly radiate it outward.  This means a plastic (really, composite) casing will absorb more heat into itself, and only slowly transfer it to its outer surface, and thus the block.  This is why both the block and outside of the casings feel cool to the touch immediately after firing in the video.  Am I making sense yet?

Sorry. Went right past me. If the casing is a poor conductor of heat, how's it remove the heat?

3) I haven't read anything about 5.56 composite rounds, so I'm afraid I can't answer that question definitively, but I believe most current 5.56 rifles have sufficient overengineering to be able to fire at least SOME rounds before requiring replacement.

The video mentioned them but didn't show them in use. Single shots makes sense. Warning labels "Do Not Fie At Full Auto" makes sense. Their being made backwards compatible so the older guns don't blow makes sense. A warning label, "Not made for these firearms with a list." makes sense.

4) Link as requested: https://bg.battletech.com/forums/fan-designs-rules/fixing-the-atow-companion-conversion-to-tw-for-mech-weapons/msg1709504/#msg1709504

Thanks!   Unfortunately, I can't open it with the good excel. The new one does but I can't do anything. Not that I understand it.
It doesn't seem to be what I'm looking for either.

5) At least one point got through!

WhooHoo!  Where's my donut? 

So how do we handle the M240 and other weapons where parts are changed? Same everything but amount of ammo?

6) No, not right.  As I explained above, the composite casing absorbs more heat into its mass vice conducting it to its exterior surface, and thus the gun.  When the casing is ejected, it takes all that absorbed heat with it, and that is MORE than the brass carries with it.

 
If the casing is absorbing the heat and taking that heat with it when it leaves, how can it transfer it to the gun? And why isn't it hot?


Watched the video again. It said that the polymer is an insulator more energy is used to push the projectile. They use 10% less propellant to do the same job.  It's about 7:50 minutes in. That would explain how it's backwards compatible. Less propellant used for the same job.

[Daryk]

The compatibility question is for TPTB.  I'm trying to solve it one problem at a time (with two locked threads to show for it so far).

Ok, physics take two: heat transfer takes time.  It takes less time through the bulk of good conductors than poor ones.  The walls of casings don't have much bulk, but the principles are the same.  Heat generated inside a brass casing is conducted quickly through the casing walls, and to the block from there.  Heat generated inside a composite casing isn't absorbed as quickly (meaning more goes to the propellant gasses, as the video described), and the that IS transferred to the bulk of it doesn't make it to the exterior of the casing before the casing is ejected.  That means the heat that WAS absorbed by the composite casing is ejected with the casing.  How's that?

I'm not really sure what you're saying about Excel... you have a version that will open it, but can't edit for some reason? 

I'm much less sure about the M240.  My impression was that it was firing the 6.8mm ammo instead of its regular 7.62mm.  That would be less damage.

What you're describing there at the end is exactly how it works.  The composite casing is taking MORE heat with it than the brass, and NOT transferring it to the gun.  That's the whole point of the design.  It keeps the gun cooler than brass casings do.  Also, compare to muzzle loaders that have to be cooled by sponging them out before reloading.  There is NO casing for those weapons, so they need to be cooled between shots.

[Hellraiser]

It certainly could use caseless ammo, but I think TPTB were deliberately vague on that point.

I'm guessing standard cased ammo for the bog standard AR.

That 3mm GDL rifle from the 1st trilogy stood out for firing a Caseless+Explosive ammunition.

But it was "special/different".

So I'm sticking with standard AR is cased. 

[RifleMech]

The compatibility question is for TPTB.  I'm trying to solve it one problem at a time (with two locked threads to show for it so far).

You'd think they'd want their games to be compatible though.    I try to ask questions and don't get any where either. 

Ok, physics take two: heat transfer takes time.  It takes less time through the bulk of good conductors than poor ones.  The walls of casings don't have much bulk, but the principles are the same.  Heat generated inside a brass casing is conducted quickly through the casing walls, and to the block from there.  Heat generated inside a composite casing isn't absorbed as quickly (meaning more goes to the propellant gasses, as the video described), and the that IS transferred to the bulk of it doesn't make it to the exterior of the casing before the casing is ejected.  That means the heat that WAS absorbed by the composite casing is ejected with the casing.  How's that?

But the casing is cool so where's the heat it absorbed?  It sounds like the heat when down the barrel but because there's less propellant the heat isn't enough to cause damage. And since the heat went down the barrel the ejected casings are cool.

I'm not really sure what you're saying about Excel... you have a version that will open it, but can't edit for some reason? 

The versions of office that come with windows now, are read only. They don't work unless you either sign in, so microsoft sees even more, or you pay for them.

So I use an older version. It works fine but doesn't open newer formats.

I'm much less sure about the M240.  My impression was that it was firing the 6.8mm ammo instead of its regular 7.62mm.  That would be less damage.

Makes sense.

What you're describing there at the end is exactly how it works.  The composite casing is taking MORE heat with it than the brass, and NOT transferring it to the gun.  That's the whole point of the design.  It keeps the gun cooler than brass casings do.  Also, compare to muzzle loaders that have to be cooled by sponging them out before reloading.  There is NO casing for those weapons, so they need to be cooled between shots.

But the casings are insulators not conductors. 

[Daryk]

The outside of the casing is cool.  Don't stick your finger inside it.  And you are correct that more energy was directed down the barrel.

Insulators are basically just really (REALLY) slow conductors.

I'll see about saving the spreadsheet in an older format.  How far back do I need to go?

[RifleMech]

The outside of the casing is cool.  Don't stick your finger inside it.  And you are correct that more energy was directed down the barrel.

Insulators are basically just really (REALLY) slow conductors.

I'll see about saving the spreadsheet in an older format.  How far back do I need to go?

I thought so. Why would I do that?
Yay!

Okay.

Thanks. I'm not sure. The Excel I use is pretty old. From Office 97. It does what I want, except open newer formats. Which usually isn't a problem. I do know monbvol's worked. Looking at them in the folder they don't even have the same icon. Weird.

[Daryk]

Ok... I'll see if I can reach that far back with a "Save As" after work tonight.

[monbvol]

Probably because I use OpenOffice.  I really need to switch to LibreOffice one of these days though.

[Daryk]

Ok, the Save As worked, but Excel told me the conditional formatting will be screwed up.  Sorry about that.  It's pretty handy to see where the break points are.  I saved it with "No" for Splash Damage and Incendiary effects, and 1 Burst with enough ammo to avoid a penalty from Reload Factor.  Please let me know if it works for you.

[RifleMech]

Ok, the Save As worked, but Excel told me the conditional formatting will be screwed up.  Sorry about that.  It's pretty handy to see where the break points are.  I saved it with "No" for Splash Damage and Incendiary effects, and 1 Burst with enough ammo to avoid a penalty from Reload Factor.  Please let me know if it works for you.

It worked. I'm not sure I follow it but it worked. Thanks  

Probably because I use OpenOffice.  I really need to switch to LibreOffice one of these days though.

I wouldn't mind using LibreOffice. It was on a different computer but it isn't available. 

[Daryk]

If you're having trouble making sense of it, just ask! 

[RifleMech]

  Asking. Sorry. It's not making sense to me.

[Daryk]

So what are you not following?  The inputs to the formula are the weapon's AP and BD, its characteristics (incendiary, splash), burst value (rounded per Herb's errata), and number of reloads.  The output in the cells of the able is the TW damage.

[RifleMech]

I'm presuming the formula is the conversion from AToW to TW, which I can follow. Slowly. I'm not sure what to do with the spreadsheet. 

[Daryk]

Adjusting the characteristics changes the values in the table.  Splash and incendiary are simply additions to a multiplier.  Burst is a little more complicated, but basically the same thing: it adjusts a multiplier.  Reload factor only reduces damage if you have less than 10 shots for a "standard" weapon, or 3 if it's support (which you switch with the "Type" dropdown).

[RifleMech]

Sorry. I know it makes sense to you but I'd need step by step instructions for it.

[Daryk]

The cells next to "Incendiary" and "Splash" (B1 and D1) are drop downs with Y or N for Yes or No.

The cell next to "Burst" (F1) is just a number field that you enter whatever burst value you want into.

The cell next to "Type" is a dropdown with "Std" for Standard weapons and "Sup" for Support.

The cell next to "Shots" is another number field where you enter the size of one "reload" (magazine).  It factors into Reload Factor (which is calculated... don't mess with the cells to the right of that) along with the Type above.

Those are the only things you need to enter.  The rest of the table is simply the computed TW scale damage for whatever AP and BD you cross reference (AP is vertical, BD is horizontal).  Beyond 18 BD, I only entered multiples of 6 (which match the TW to AToW scale conversion) to see how close they were at AP 10.

Does that make sense?

[RifleMech]

So these are numbers I'm supposed to put into the AToW Conversion formula?

[Daryk]

What I outlined above are basically that, yes.  The only numbers that go straight into the formula are Burst and Shots (which you enter), and AP and BD (which are just part of the table).

Splash and Incendiary characteristics add numbers to multipliers (Incendiary a +2 to AP in the Penetration Factor, Splash a +1 to the term that multiplies BD for the Damage Factor).  Type tells the sheet which Reload Factor formula to use.

[Daemion]

Doesn't matter if they do, Armor weakens after each successive hit regardless if it penetrates or not. This is why things like motorcycle helmets should be checked after a drop from a good height. Armor designed to handle stronger impacts either need to be incredibly thick and heavy to resist that weakening, or use self destruction to handle it. Battletech armor is handled very much of the self-sacrificing variety which means it can be degraded by multiple small hits.

The Highlighted for emphasis gets this reply: I see BT armor as a combination of deflective and ablative properties. Otherwise, there wouldn't be such high to-hit values in-game.  You'd be rolling location and assigning damage only.  Which means it lasts longer than what you would think it should. 

I found my justification for how I see things working. 

[RifleMech]

What I outlined above are basically that, yes.  The only numbers that go straight into the formula are Burst and Shots (which you enter), and AP and BD (which are just part of the table).

Splash and Incendiary characteristics add numbers to multipliers (Incendiary a +2 to AP in the Penetration Factor, Splash a +1 to the term that multiplies BD for the Damage Factor).  Type tells the sheet which Reload Factor formula to use.

Okay. Thanks.

[Daryk]

Victory?   

[RifleMech]

I'm still not sure what to plug in where but that's okay. I'm not really sure how to do anything with AToW.

[Daryk]

Ok, here's an example:

For a bog standard Auto-Rifle, you would enter N for Incendiary, N for Splash, 15 for Burst, Std for Type, and 30 for Shots.  Then you'd look in the table cross-referencing 4 AP and 4 BD.  The value in that cell is 0.52, exactly what you'd expect it to be.

Does that help?

[RifleMech]

 

Sorry. No. I know it makes sense for you but I can't find a .52 on the table. Where's the AP and BD?

[Daryk]

The AP are in column A (from Row 2 to 12), and BD is in row 2.  It's an AP vs. BD table...

[RifleMech]

Okay...

And on to more stupid questions.

Infantry weapons are either single shot or burst right? So if two single shot guns both have the same AP/BD they should do the same damage in TW, right? So why don't they in TW? Nearest I can figure is that total payload is factored into the TW damage but if they're only firing single shots, the total payload shouldn't matter. Right? Or am I missing more things?

[Daryk]

It sounds like you're discussing Reload Factor.  I agree it's odd, but it is part of the conversion.  Disposable weapons get around Reload Factor but must track ammo.  Personally, I think tracking ammo is better than the abstraction of Reload Factor.