Speed alone does not indicate what your pin gap will be. A FAR more important measurement is the sightline distance, or the measurement from your peep or eye to your sight pin. This distance has more effect on your pin gap than changing speed.
Here's an example

using a common cabon arrow and 3" vanes on both)
Arrow speed: 280 f/s Peep to pin measurement 30"
The gap from 20-50 yards is 13.14mm (.52 inches)
Arrow speed: 270 f/s Peep to pin measurement 28"
The Gap from 20-50 yards is ALSO 13.14mm!
Now lets keep the speed the same and only change sight length:
280 f/s 30 inch sight length
Gap from 20-50 yards 13.14mm
280 f/s 28 inch sight length
Gap from 20-50 yards 12.33mm
To make a long story short............
If you want close pin gap, shorten your sightline distance!
Happy Shooting!
>>>------Tony Virnoche------>>>
>>>---The Archery Program--->>>