I'm quite fond of that scope and recently bought my second one. I have it mounted on my Remington Model Seven Predator in .17 Fireball. It is a good fit on the smaller rifle. The exterior dimensions of the 7-21 are actually a bit less than the lower powered 4-12 and 5-15 scopes. I've also owned both of those.
The power range of this model seems excellent to me for warm or hot weather long range shooting. For me at least mirage seems to make much more magnification a bit iffy when the temperature climbs to the high 80s or more. The optics are excellent and mechanical performance is dead on. They are an excellent buy for the money. I think I paid about $358 for mine at Midsouth Shooter's Supply a GBO Sponsor.