Questions about how some things work

[Jancarius]

I don't think it should work that way at all.  To me, a wizard capable of using technology in the Dresden-verse would be like a fae taking the aspect 'Iron-tolerant'.  It just flies in the face of a basic concept of the game-verse.

[Kommisar]

DU Aside:

A thin layer of DU in a vault door would be used to make it much harder to drill through as well as limiting the use of high end shape charges to penetrate and compromise the sealing shafts.  You don't go to home depot for a bit that will even smudge DU.

Also, some additional thoughts of making small arms DU rounds.  You will have to do one of two things for it to work.  One, you will have to use custom smooth bore barrels on the weapon you are using.  Two, make DU cored rounds with a softer metal jacket.  Otherwise, you will foul your barrel after one or two rounds as the DU rounds will not deform around the barrel groves and, as a result, acquire the stabilizing spin.  Possibly with catastrophic results depending upon the the weapon and round design.  The barrel will deform around the DU round instead.  And before you think that going the DU core round route, there are difficulties there that make it much harder to pull off that most would think.

First, creating core rounds is more difficult than just dipping the core in the softer metal.  I'm not going to go into a long post on metallurgy here, but you will have challenges in keeping the softer jacket material (less dense) to bond with the DU core (more dense).  Not done properly, your jacket material will simple strip off once fired and leave you with a DU core ricocheting down your barrel.  A barrel which is now fouled with the remnants of your jacket metal.  If it was a burst of automatic fire then the second and third rounds are going to do God-Knows-What.  But I would not want to be holding the weapon or even standing near the weapon for this experiment.

This can be done properly.  It takes skill, knowledge (above what any common gunsmith would have) and specialty tools and materials to pull off.

You may be able to design a small sabot round system.  But that would require a smooth bore itself as well as some very careful machining of the sabot core itself to ensure a properly engineered shape for stable flight upon casing separation.  VERY expensive.

Cheaper, easier option would be to make a DU shotgun round.  Already smooth bore and capable of firing off a mixed DU buck-shot round or an easier to design and make sabot round.

Oh, and the other problem with DU rounds in small arms is that it will reduce your ballistic performance all around.  DU is heavier than lead by about 70%.  Add to the decrease in performance if you are using a smooth bore option.  A .50 cal round will still have a good amount of powder behind it such that you will not lose a lot of that performance (assuming you kept the rifling or a well designed sabot), but any smaller rounds will start seeing severe issues with range, accuracy and KE on impact.

With all that said (and assuming anyone actually read any of it and cares) if you are going for a more cinematic type game (think Blade with all his specialty rounds) then go for it and have fun.  But, if you are going more gritty/realistic then now you have some good background to use when you tell your player how hard it is to get and use DU rounds for his M-16.

[UmbraLux]

Sabot rounds are the way to go - and not all that difficult.  They will work in a rifled barrel and you can purchase sabot reading kits.  Still going to have issues acquiring and machining your DU rounds, of course.

Edit:  Since you're bringing this much realism into the game one reminder - never fire a sabot round through a weapon with a muzzle break!  Bad Things (TM) may occur...

[toturi]

I don't think it should work that way at all.  To me, a wizard capable of using technology in the Dresden-verse would be like a fae taking the aspect 'Iron-tolerant'.  It just flies in the face of a basic concept of the game-verse.

As I said, the workaround may not be for you. If you do not want a player to play a character that has a concept that turns a basic game-verse concept on its head, then it is your decision.

It just does not seem so to me. A fae may be iron-tolerant but he can still have an Iron Catch for his Toughness powers. The younger magic users and less talented magic users also seem to have technology run awry less too.

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Binder (who is supposedly quite talented in his area) had a cellphone.

[Jancarius]

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Binder is more a focus practitioner.  He can do one thing, pretty well.

  The party, however, consists now of 3 people who are more on Victor from Storm Front's level in terms of magical power.  Obviously, it's not 'use any magic, never see internet' because the Alphas seem to have no technological problems at all.  But at some point in the range between Billy and Harry, technology has to start to fall apart.  They also note in the hexing rules (and I think it has been implied once or twice in the series) that the age of the mage relative to the technology seems to matter, which would be to me why Molly can use more tech than Harry (In addition to the fact that she probably has higher Discipline relative to Conviction than Harry does, and that Harry flat out has more raw power in the form of Refresh).  What I'm trying to figure out is how to handle this lower level hexing.  I don't want them to have their cars break down everytime they get in them, for example.  And the shaman, at least, has a 'beat up old chevy' of some unspecified year that he drives specifically for that purpose.  And clearly, they must still be able to at least use computers some of the time.  But I'm trying to figure out how to model a highly increased chance of hardware and software problems resulting from their magic in a story telling way.  I don't intend it to be something that really screws up their lives, more of a "you've noticed that lately, your computer crashes.  A lot."  and only really treat it as a compel if it's something like "Sheridan, your gun jams on the second shot" as a side effect of the evoker sorcereress throwing around blasts of power.

Now for a sponsored magic question:  Rather than having the shaman be just another sorcerer in a party now consisting of three of those, I suggested we put together a sponsored magic for him, where the sponsor is his ancestral spirits.  His trouble is already Ancestral Pact, and I think it ties in better with his high concept of Runaway Native American Shaman.  So far, I was thinking the standard 4 point cost, with the ability to perform certain nature magics with evocation like-methods and speeds.  What I'm kind of at a loss at is how wide should I allow nature to be defined (cause with some finangling, almost anything can be 'nature related'), and what sort of restrictions/drawbacks should I give for his sponsor?  In the story, he's already called up one spirit to ask it about the Sin Eater, and I didn't really know what to have the spirit demand in return, so I just said he had 'debt' to the spirit now.

Also, thank you much Kommisar: I know next to nothing about guns, despite living in Texas, so having anyone more familiar with them provide information I can reference is extremely helpful. 

Sabot rounds are the way to go - and not all that difficult.  They will work in a rifled barrel and you can purchase sabot reading kits.  Still going to have issues acquiring and machining your DU rounds, of course.

Edit:  Since you're bringing this much realism into the game one reminder - never fire a sabot round through a weapon with a muzzle break!  Bad Things (TM) may occur.

What's a sabot round?  Also, he started asking me about explosive rounds yesterday, and how much of a damage bonus those would get relative to a normal round...  I first made it clear that regardless of whatever the actual law on explosive rounds are, in my game, they are a illegal (In-character illegal, not banned from game) round, but beyond that I don't really know much about them.

[noclue]

I don't think it should work that way at all.  To me, a wizard capable of using technology in the Dresden-verse would be like a fae taking the aspect 'Iron-tolerant'.  It just flies in the face of a basic concept of the game-verse.

I think technology should fail at the least opportune moment, creating the most dramatically tense and interesting moment, and sending the story off in new exciting directions full of highly charged conflicts. when you see those moments be ready with a compel. and do your best to create those moments in play.

[devonapple]

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Binder is more a focus practitioner.  He can do one thing, pretty well.

 

True, but then in White Night

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you have one Minor Talent with no overt tech in her home at all, which Harry comments upon as general evidence that a minor practitioner of some sort lives there

. He gives the impression that most practitioners of any talent start having troubles with even basic domestic technology. Ultimately, each of these instances came down to different narrative needs.

The rules make it very hard to justify anyone using a computer consistently. "How would they get through school?" people ask. "How do they function in college?" In an ideal world, the White Council would get a tip-off when unexplainable things (attributable to hexing) happened in a classroom, and those budding practitioners would be assessed, and either pulled into the Wizard's world if worthy, or taught to control their energy to function more smoothly in the mundane world.

But it isn't an ideal world, and almost all of these minor practitioners are just out of luck as far as fitting in, until they find some way to capitalize on their abilities. And sadly, usually, that's joining a Cult, creating a Cult, or otherwise developing sketchy magics to get by.

This isn't a game about social justice, however, so if it is in the table's idea of fun that a plucky group of teens/college students are able to juggle life as minor practitioners as well as life in contemporary technology-dominated society, then great! And when the GM wants to make that tech a little unreliable, boom! Fate points.

[Kommisar]

No problem on the gun/tech help.  Grew up in a military family and am now an engineer (and geologist; long story)... so it's good to have some practical use for the vast array of otherwise useless knowledge and skills my father imparted upon me.

A sabot round is, essentially, a round that contains 2 basic parts.  One is the actual projectile (in this case the DU core).  The second is a casing shell that contains the core until the round leaves the barrel and is then shed.  Wikipedia has a good article on it.  I will admit to being completely unaware of the availability of purchasable kits for civilian small arms sabot rounds.  Largely because I have never had need of one nor can I possibly think of a single reason a civilian (or 99% of soldiers) would need it beyond the "COOL!" factor.     So, with that available, that would be the way to go.  Assuming you can clear the procurement and machining hurdle.

I have little experience with explosive small arms rounds.  Largely because they are both illegal (highly) and that the military does not employ them commonly (if at all).  20mm, 30mm and 40mm explosive rounds, sure.  Even .50 caliber.  Heck, the Marine Corp is now deploying HE 12 gauge rounds for use in the their Remington and Mossberg pump shotguns.  Something like explosive 7.62mm, 5.56mm and other common rifle and pistol rounds not so much.  Let me talk to one of my "peeps" and I'll get back to you.

[Jancarius]

What would be the advantage of a sabot round?  Just using it with an unusual rifling? 

What are some things that would set off red flags with the ATF so I can hastle him with them periodically?

What kind of obstacles would someone typically face in operating their own personal armory?  He, under the bar he owns, has a fortified room which has a large number of shotguns, pistols, and is often where he stores his 50 cal and keeps his suit of body armor.  I don't want to hastle him illegitimately, I just want him not to be able to operate as a uninterfered with personal military base.  There's a reason people don't just have those in their houses, and his character had a section 8 discharge from the military (he saw and reported a battle between the White Council and Red Court vampires).  He wants to be a member of a PMC somewhat, but I'm iffy on that, as I can't see a way to make that materially a disadvantage to counter the fact that he would just go "I draw on the legal and procurement resources of my PMC" especially since I know virtually nothing about hte relevant laws and business practices.

True, but then in White Night you have one Minor Talent with no overt tech in her home at all, which Harry comments upon as general evidence that a minor practitioner of some sort lives there. He gives the impression that most practitioners of any talent start having troubles with even basic domestic technology. Ultimately, each of these instances came down to different narrative needs.

The rules make it very hard to justify anyone using a computer consistently. "How would they get through school?" people ask. "How do they function in college?" In an ideal world, the White Council would get a tip-off when unexplainable things (attributable to hexing) happened in a classroom, and those budding practitioners would be assessed, and either pulled into the Wizard's world if worthy, or taught to control their energy to function more smoothly in the mundane world.

But it isn't an ideal world, and almost all of these minor practitioners are just out of luck as far as fitting in, until they find some way to capitalize on their abilities. And sadly, usually, that's joining a Cult, creating a Cult, or otherwise developing sketchy magics to get by.

This isn't a game about social justice, however, so if it is in the table's idea of fun that a plucky group of teens/college students are able to juggle life as minor practitioners as well as life in contemporary technology-dominated society, then great! And when the GM wants to make that tech a little unreliable, boom! Fate points.

I do want to make that tech unreliable, but 2 of the three would be much more impacted/expected to use tech than the others.  The changeling sorceress is an undergrad (as is the werewolf, but her hexing power is nil), so would at my university be expected to do a number of online/computer courses.  The shaman is a phd student, and so he would probably need to make frequent use of the electronic resources.  The third character, a painter, is basically unaffected by his own hexing.

[sinker]

I think technology should fail at the least opportune moment, creating the most dramatically tense and interesting moment, and sending the story off in new exciting directions full of highly charged conflicts. when you see those moments be ready with a compel. and do your best to create those moments in play.

Agreed. Accidental hexing is usually a compel of their high concept. In that way it should be like any other compel. It needs to have impact on the story and it should be a negative consequence (not a capital C Consequence, but you know what I mean). Other than that it seems like your group is diverse enough in their power sources to have them running around with tech on a regular basis. It's arguable that your shaman (actually having sponsored magic) need never worry about it, though you can still compel him if you like. Seems like your sorceress and your painter would have the most issues, being actual mortal practitioners.

Now for a sponsored magic question:  Rather than having the shaman be just another sorcerer in a party now consisting of three of those, I suggested we put together a sponsored magic for him, where the sponsor is his ancestral spirits.  His trouble is already Ancestral Pact, and I think it ties in better with his high concept of Runaway Native American Shaman.  So far, I was thinking the standard 4 point cost, with the ability to perform certain nature magics with evocation like-methods and speeds.  What I'm kind of at a loss at is how wide should I allow nature to be defined (cause with some finangling, almost anything can be 'nature related'), and what sort of restrictions/drawbacks should I give for his sponsor?  In the story, he's already called up one spirit to ask it about the Sin Eater, and I didn't really know what to have the spirit demand in return, so I just said he had 'debt' to the spirit now.

I'd encourage you to narrow the definition to specific parts. Keep in mind that with summer magic (one that could be most justified in having nature as a element) they narrow it down to "evocation
spell effects that encourage wildness, birth, growth, renewal, and warmth." Then again those are all pretty broad categories as well, so maybe you don't have to worry about it being so. Anyway if you feel it's too much then you could always ask him to pick a specialty (I.E. maybe there's a portion of the natural world that he feels closest to).

[UmbraLux]

But I'm trying to figure out how to model a highly increased chance of hardware and software problems resulting from their magic in a story telling way.  I don't intend it to be something that really screws up their lives, more of a "you've noticed that lately, your computer crashes.  A lot."  and only really treat it as a compel if it's something like "Sheridan, your gun jams on the second shot" as a side effect of the evoker sorcereress throwing around blasts of power.

I'd suggest compelling 'per scene' or even 'per session'.  I'd take a fate point later to end the compel, but the compel itself would last the entire scene at minimum.  For technology central to the story, I'd even go 'per adventure'.  For example, if the group wanted a Shadowrun style data steal run, I'd compel the Wizard the first time he touched the network the data resided on and tell him that compel is in place for the entire adventure (escalate the compel if needed).  Essentially, the compel is about him finding an indirect method of getting data off the computer - not about sitting down and typing at it once.

Now for a sponsored magic question:  Rather than having the shaman be just another sorcerer in a party now consisting of three of those, I suggested we put together a sponsored magic for him, where the sponsor is his ancestral spirits.  His trouble is already Ancestral Pact, and I think it ties in better with his high concept of Runaway Native American Shaman.  So far, I was thinking the standard 4 point cost, with the ability to perform certain nature magics with evocation like-methods and speeds.  What I'm kind of at a loss at is how wide should I allow nature to be defined (cause with some finangling, almost anything can be 'nature related'), and what sort of restrictions/drawbacks should I give for his sponsor? 

I'd err on the side of allowing its use.  As long as his in-character explanation is reasonable, it works.  (This is in line with the book's advice on using elements.)  As for goals / agenda, I'd say the ancestor spirits want to defend and promote 1) their specific tribe, 2) the Native Americans, and 3) their way of life.  So they're probably not going to assist land development projects...

Also, thank you much Kommisar: I know next to nothing about guns, despite living in Texas, so having anyone more familiar with them provide information I can reference is extremely helpful.  What's a sabot round?  Also, he started asking me about explosive rounds yesterday, and how much of a damage bonus those would get relative to a normal round...  I first made it clear that regardless of whatever the actual law on explosive rounds are, in my game, they are a illegal (In-character illegal, not banned from game) round, but beyond that I don't really know much about them.

Sabot rounds are used for hunting and target shooting.  They allow hunters to shoot small game with a large caliber rifle (you can put .22 bullets in .30 shells and hunt deer or rabbit simply by switching ammunition).  Sabot rounds also shoot flatter and with a higher velocity (assuming same bullet composition*) which makes them good for long distance target shooting.  I probably wouldn't give a damage bonus, you're firing a smaller round at a higher velocity - call it a wash for game purposes.

*You lose the velocity and flat trajectory benefits if your sabot round has the same (or more) mass as a normal round.  So you probably would not gain this with DU. 

Kommisar covered what a sabot round is, here's a series of pics showing sabot separation.  These show the plastic sabots before and after reloading the rounds.

What would be the advantage of a sabot round?  Just using it with an unusual rifling? 

Basically the two noted above - use a big rifle for small game and shoot flatter trajectories.  You do gain a side benefit of less barrel fouling - the bullet doesn't touch the rifling, just the sabot. 

What are some things that would set off red flags with the ATF so I can hastle him with them periodically?

To the best of my knowledge, normal sabot rounds are legal in areas where ammunition is legal.  DU is another story...

What kind of obstacles would someone typically face in operating their own personal armory?  He, under the bar he owns, has a fortified room which has a large number of shotguns, pistols, and is often where he stores his 50 cal and keeps his suit of body armor. 

The bar is a problem.  It's illegal to bring a firearm into establishments which make some portion (I don't know the exact percentage - and it changes from one state to another) of their business off of alcohol sales.  That alone would get him arrested, have the bar's alcohol license revoked (since he's the licensee / owner), and probably have the weapons confiscated.  Fines and jail time are possible depending on prosecutor and judge. 

There's also a law currently in progress to make it illegal for 'mentally unfit / unstable' people to own / purchase firearms.  I fairly certain a Section 8 would get him looked at if that law is passed in your campaign...

[Kommisar]

Unless your game is the Volunteer State!  As of last year it is completely legal here in Tennessee to bring firearms into bars and, well, any other establishment that does not house our politicians.  Including concealed carry.  Currently, owners can choose to ban weapons on their premises, but there is a push in our legislature to do away with the right of a property owner to prohibit weapons on his property.  Not sure if it will go through or not.  Best bet for anyone running a game with a gun-bunny character that wants to keep it real is to go online and look up your state and municipal firearm laws.  They can vary wildly from state to state.  Or even  among cities/counties in the same state when you get down to certain particulars like storing them in a place of business or discharging the weapon.  Or even in how the weapon is classified.  A guy in Knoxville made this AK-47 conversion that shortened the barrel, removed the stock, removed the brackets such that it could not use a sling, kept the 30 round banana clip and took it to the local park wearing camo and tactical gear.  He then proceeded to stalk through the park and, in the process, scared all the moms there with their kids to death and created a general panic.  He ended up being detained by the police but, due to the conversions he had made on his AK-47, it now fell into the pistol category.  Therefore, it was completely legal for him to carry it into any state and city parks.  He is now suing the state for wrongful detention and harassment. 

For an amusing aside, I recently did that research for my little town here in Tennessee in regards to dealing with a nasty groundhog problem and discovered that my city has a long list of prohibited projectiles that includes; I crap you not, and I quote,  "Snowballs thrown with malicious intent."  No mention of arrows though in that page long list...

In 90% of states, though, you would be in deep bantha poodoo for having an armory under your bar.

Looking at the links provided (thanks UmbraLux; I don't hunt so I hadn't seen the non-shotgun sabots) if you have the money you can buy as many sabot round kits as you can afford.  The Remington 12 gauge sabot shells are around 22 dollars for a box of 5 according to the internets.  I doubt the ATF is really tracking those much.  At least no more than they do normal ammunition purchases.  Which, they do track and follow up on someone buying bulk ammo.  Congress and certain state legislatures are currently throwing around bills that would ban the ATF and other agencies from doing that; but as of right now, they do.  Largely as part of efforts to head off smuggling down to Mexico and the cartels.  You can still buy pallets of all the ammo you want!  All nice and legal.  It just means you will be getting looked at.

FYI, Section 8 Discharges are no longer used by the military.  Army Regulation 635-200, Active Duty Enlisted Administrative Separations. Chapter 5, paragraph 13 (thanks Dad!) now covers discharges for personnel with medically diagnosed psychological conditions.  AR 635-200 took effect back in 2005.  So, it would depend on the character's history and how much of a stickler you wish to be.  If they were drumming him out for having reported vampires and thought he was PTSD or such, he would get a Involuntary Chapter 5-13.  That is if they really wanted him out and pressed it.

Those dishonorably discharged from the United States Military and those having been adjudicated as mental defectives or incompetents; both of which this character could fall into; are prohibited by the Gun Control Act of 1968 for owning a firearm.  And, yes, this means anyone drummed out the military for being a homosexual can never own a fire arm ever again.

This makes life hard for this character.  Very hard.  It means that anything he is purchasing and procuring is either black-market, purchased from a dealer not doing his proper checks, from personal sales (which are not monitored) using the gun-show loophole.  But, the moment he shows up on the ATF's radar, he's in for a full on federal warrant search and seizure visit.  And these guys are really, really good at finding hidden gun vaults and the like. 

NOW, if his command did not hate him and he had some friends in the chain; they would have told him what the bureaucratic tea leaves were reading for his future in the military and it would not have been hard to get him a voluntary discharge for a wide range of reasons.  Which would allow him to legally own firearms.


SABOT ROUNDS.  The purpose of a saboted round is to allow one to fire a smaller projectile with the energy normally reserved for larger rounds.  Such as putting a 7.62mm tungsten alloyed armor piercing round inside a .50 cal sabot so you can fire it out of your .50 cal weapon with all the energy of that .50 round behind it.  This is useful in armor piercing applications mostly.  Or, in the civilian hunting arena, as I have learned, to be able to fire smaller rounds without needing to carry a different weapon.  Shotguns use it to gain a great deal of additional accuracy and energy over range.  A DU round would use a sabot round to keep the DU core from tearing your barrel to crap.

EXPLOSIVE ROUNDS.  A lot of the time, people will refer to incendiary tracer rounds as "explosive" rounds.  This occurred often in accounts of their use on the Eastern Front of World War II.  Especially from accounts of snipers on both sides.  There were actually explosive rounds and still are.  They are utterly prohibited by all sorts of various international treaties such as the Hague and Geneva Conventions from being used against human/non-materiel targets.  They were used on the Eastern Front of WWII because Lenin removed the USSR from all previous "Tsarist" international treaties and the Germans and Soviets really hated each other at that point.  All German snipers were strictly verboten from taking any explosive/incendiary rounds with them if they were transferred to other theaters.

True explosive rounds are designed for armor piercing; which is legal under all those treaties.  They work not by some fancy, miniature fuse system in the round itself.  They have a magnesium or phosphorus tip that ignites upon impact due to the KE of the impact which, then, detonates the explosive core behind the tip.  There are many, many variations of exactly how this works.  Most of them are designed to work in 20mm and larger rounds.  Largely for aircraft, attack helicopters, and AFVs.  They do make .50cal explosive rounds for use on armored targets.  The problem is, if you shoot a soft target with them (say a human), the bullet will punch right through them and not detonate as nothing will create enough frictional heat to ignite the incendiary.  Not even body armor would be enough to set it off.  Maybe!  Maybe if you hit the strike plate of the really heavy duty military issue body armor.  Bigger rounds can and do use mechanical fuses as well, but getting one to work in even a .50 cal round would be tough.  Anything smaller is nearing impractical and/or extremely expensive.

As for doing more damage.  It's blow through.  You hit a human target with a .50 cal round inside effective range, do you really think that having it go boom will make any bit of difference to anyone but the forensics team that shows up later?   

Having HE rounds used in a firefight in the US is a good way to have every federal law enforcement agency and Homeland Security crawling over your city like ants in a kicked over hive.  No one with any brains is going to see enough effectiveness out of their use to risk the attention it will bring.

[zenten]

True explosive rounds are designed for armor piercing; which is legal under all those treaties.  They work not by some fancy, miniature fuse system in the round itself.  They have a magnesium or phosphorus tip that ignites upon impact due to the KE of the impact which, then, detonates the explosive core behind the tip.  There are many, many variations of exactly how this works.  Most of them are designed to work in 20mm and larger rounds.  Largely for aircraft, attack helicopters, and AFVs.  They do make .50cal explosive rounds for use on armored targets.  The problem is, if you shoot a soft target with them (say a human), the bullet will punch right through them and not detonate as nothing will create enough frictional heat to ignite the incendiary.  Not even body armor would be enough to set it off.  Maybe!  Maybe if you hit the strike plate of the really heavy duty military issue body armor.  Bigger rounds can and do use mechanical fuses as well, but getting one to work in even a .50 cal round would be tough.  Anything smaller is nearing impractical and/or extremely expensive.

As for doing more damage.  It's blow through.  You hit a human target with a .50 cal round inside effective range, do you really think that having it go boom will make any bit of difference to anyone but the forensics team that shows up later?   

I'm thinking some monster with Mythic Toughness or the like is the intended target for something like that.

[Kommisar]

True, and that is sort of what I figured.  But, this falls completely outside the realm of physics as I understand them.  It would have to be the call of any GM/group as to how such a round would interact with any given supernatural critter/god/goddes/deamon.  At least, that is my opinion.  After all, while there is one power called "Mythic Toughness" I can see many different means by which a supernatural entity could come by that power.

Were I to run it, I would give something like a .50 cal (12.7mm) to 20mm HIEAP (High Explosive Incendiary Armor Piercing) round such as the Mk211 Mod 0 .50 cal round I would slap on an AP 3 rating for the weapon.  Meaning, it would ignore 3 levels of Armor on any given target.  A round that large would be a Weapon 4 already and I would not change it.  If reasonable, I would allow for hitting a flammable target to be justification for dropping a non-sticky aspect of "Ignited" on the scene.  Essentially a maneuver using Guns Skill.

For a DU sabot round at .50 cal such as the M903 SLAP (Saboted Light Armor Penetrator) but changing out the normal Tungsten heavy allow penetrator for one made of DU, I would allow for it to satisfy the catch for certain critters and spirits, AP rating of 4 and keep it as a Weapon 4.

For shooting out vehicles and other light armored or inanimate soft targets, I would actually treat it as a maneuver since we really don't have stats for things like cars, trucks and AFVs.  And after years of GURPS, I have no interest in building a whole book just for vehicle stats nor do I see a need.  IMHO, using a .50 BMG round is rational enough to justify making the maneuver against the vehicle using your Guns Skill.  If successful against either the targets Endurance or the drivers Drive Skill, you can drop an appropriate aspect on the vehicle.  Such as "Cracked Engine Block" or "Ruptured Fuel Tank".  Compel as you will from there.

[UmbraLux]

I like the idea of adding AP without changing the Weapon rating, Kommisar.  It avoids a certain game's constant escalations...