My maga wants to make an enchanted crossbow with a few magical abilities:
Rego Terram: 18
Base: 4 [Control Metal (the string) in a slightly unnatural fahion]
Range: Personal [+0] It only affects the crossbow
Duration: Momentary [+0] It only needs to snap into loaded possition
Target: Individual [+0] maybe Part [+1]
Constant Effect: [+10]
Only she can use it: [+3]
2) Silent Fire <---- Will this make the arrows bounce off Parma?
Perdo Imaginem 12
Base: 1 [Remove 1 sense]
Range: Sight [+3]
Duration: Momentary [+0]
Target: Individual [+0]
Only she can use it [+3]
12 times per day [+5]
Muto Herbam (Terram) 14
Base: 3 Slightly unnatural (Lighter wood and metal)
Duration: Sun [+2]
Target: Individual [+0]
Uses per day: 2 [+1]
Environmental Trigger [+3]
- Just the string, she is not so strong, so she wants some "help" with pulling the string back. She will place the bolt herself after it loads.
I mean unlimited uses, not constant effect
The bolt flying through the air, so it can negate the shriek of impending shafts spell
maybe create a tunnel of no sound in whhich the bolt flies so that it is not enchanted, still silent
If a fireball flying towards the target is momentary, it should be momentary with a crossbow bolt as well.
Momentary duration should cover a round for these purposes.
The 'Silent Fire' effect I'm confused by. What is it silencing?
If it's silencing the crossbow itself, r: personal would be fine. It'd also not need to penetrate, because the bolt isn't being enchanted.
If it's silencing the crossbow bolt, r: touch would be fine, as the crossbow is touching the bolt at the point it is fired. It would need to penetrate, because the bolt is enchanted.
The vast majority of the noise of a crossbow firing is the crossbow itself going 'twang', or the noise of the reloading ratchet. The bolt itself makes very little noise until it hits something.
It is very hard to isolate the location of a hidden shooter even after they fire their first shot. This is true even if the shooter is using an un-silenced firearm. Adding a silencer does surprisingly little; people track firearms by muzzle flash. Crossbows don't have a muzzle flash, which makes them very stealthy weapons. You're only going to have to worry about the sound of the crossbow (or bolt) if you're firing in an unnaturally quiet area at close range.
What's the trigger on Silent Fire? Is it just "the first 12 shots each day are silent?" Because I don't see why you're not making it unlimited-uses, like the self-spanning crossbow.
I agree, you're probably better off silencing the crossbow itself to avoid getting the bolt pink-dotted. Silencing the bolt will not protect it against Shriek of Impending Shafts because the only one who hears that is the magus who cast it. (Also? The way around that would be to use metal bolts.)
My own variant on the autoloading crossbow was here: https://forum.atlas-games.com/t/intellego-and-warping/142/1. I ruled that spanning an arbalest immediately was "very unnatural," though you went with "slightly." Also, since I made the crossbow magazine-fed and the bolt autoloading, I added a +1 complexity modifier to the enchantment.
You could just look up the invisible sling of Villano and use that for the effect in some ways. That's how I'm building mine. Though I did realized that it unfortunately is therefore a 'bolt launcher' or 'bolter'
Get your WH40K out of my Ars Magica
Also, would you aim the crossbow using Crossbow skill, or Finesse?
Though that does give me a thought: firearms will appear in 1260. So let's just enchant a hollow metal tube as a stonethrower...I wonder if there have ever been any firearm rules in Ars Magica? In a long-running saga, handgonnes and cannon will appear and become increasingly relevant, and some crazed Verditius is bound to get ideas.
Hey! I am NOT crazy!
(Seriously, that's part of the long term plans for my character)
I'd discuss it with your SG, but it depends. If you're using a crossbow-like body and such, I'd personally be prepared to accept that as you use it, it's like a bow. At least in the Sling of Vilano kind, since that is then natural flight by being carried by the air, resulting it it experiencing the slowing and dropping effects as the air ahead of it tries to grab ahold.
2) The bolt flying through the air, so it can negate the shriek of impending shafts spell
I don't think that'll work. Shriek of the Impending Shafts doesn't sense incoming missiles by their sound. It detects a wooden object on collison course with you, and then it makes a sound to alert you. SO a PeIm effect om the crossbow or missiles won't work. You would need to ensure the target does not have Shriek of the Impending Shafts running or that it fails. But how?
IMHO the sound produced with this spell is a cosmetic detial. An Intellego spell senses or detects something, and the caster is alerted to the fact. It could as easily have given him mental information that: " a missile approaches from your 5 o'clock".
The spell could be circumvented if the missile was not wooden but some other material. But If a MuHe(something) is in effect on the bolt, it would be magical and thus be resisted by PM.