Spotting Scope vs. Rifle Scope

Hey guys,

I've got a bit of a strange question for you, but I'd be interested to hear some opinions...

I am looking for an optic that will allow me to see 20 calibre bullet holes in normal paper targets out to roughly 400 yards. I am trying to decide if a good rifle scope would do this as well or better than a mediocre spotting scope.

I am trying to decide between an inexpensive spotting scope (like I bushnell Trophy or Ultima 65) - or getting something like a Vortex Viper HS 4-16 and seeing if that has enough clarity and magnificiation?

My logic is that I really only have use for a spotting scope a couple of times a year while sighting in or maybe for a gopher hunt.. but I do have a rifle I could put the Viper HS on and use more frequently.

I can justify 500 - 600 bucks for a rifle scope I'll use regularly but I don't think I can justify spending more than a couple hundred on a spotting scope I'll use twice a year.

Would a more inexpensive spotting scope even have enough clarity at ranges like that?

Thanks for the input