It seems that their is some bleed-over from previous editions. Counterspell and Dispel Magic are different spells that do different things with different casting times and ranges. Why would you allow Dispel Magic to substitute for Counterspell but not Magic Circle, Phantom Steed or Leomond's Tiny Hut?
I beg to differ
http://www.sageadvice.eu/2015/12/11/can-silence-interrupt-a-spell-caster/
And with this answer I see no difference in dispel magic
It seems that their is some bleed-over from previous editions. Counterspell and Dispel Magic are different spells that do different things with different casting times and ranges. Why would you allow Dispel Magic to substitute for Counterspell but not Magic Circle, Phantom Steed or Leomond's Tiny Hut?
Dispel magic can target a magical effect. Wouldn't a fireball that has left a caster's hand but not exploded to inflict damage be a valid target? If it must move through the air, couldn't that movement be readied against at a desired point in the trajectory, much as you could a moving enemy?
It seems that their is some bleed-over from previous editions. Counterspell and Dispel Magic are different spells that do different things with different casting times and ranges. Why would you allow Dispel Magic to substitute for Counterspell but not Magic Circle, Phantom Steed or Leomond's Tiny Hut?
Bullets are kind of ridiculously fast, so I'm not sure that's a fair comparison. A better comparison would be with a baseball. (I'm pretty sure that we're talking about Dispelling the Fireball as it's forming, though - before it's launched.)The depends on what you consider 'instantaneous' to mean, and reaction time. The average reaction time to a visual stimulus is 1/4 to 1/2 a second. If the streak of light of a fireball is even as slow as a bullet, it's about 2,500 feet per second. With a range of up to 150 feet it would reach the target in 1/16 of a second or less, long before the readied action could be released.