Re: Scope for squirrels at 400 yards?
magnification, retcule patterns etc. is all a matter of taste. However I suggest you get something with 1/4 MOA adjustments, not 1/8th. You'll get between 10 and more likely 15 MOA movement per turret revolution from most 1/4 MOA scopes and only half that from the 1/8 MOA scopes.
Therefore if you shoot at 400 yards you will most likely use around 7 1/2 MOA elevation from a 100 yd zero. That would be all of, maybe more than a full rev of the elev knob. IF you have never missed a target because you were one (or more) full revolutions off, and didn't realize it, then you haven't shot alot of long range stuff yet. Sooner or later you will do it.
The only reason 1/8th or 1/16th clicks exist is to make a false click have less error to it. If you over rotate and and then finish your adjustment with a few "Clockwise" clicks, you eliminate any false click movement, or should I say lack of movement.
In my experience, if a shooter shows up on the line with a scope that has 1/2 MOA or better yet, full MOA clicks, he probably is not new to LR shooting. He will make up any 1/4 MOA diff with slight hold over or under.
Of course, the BEST thing to use is the "best thing" you already own, at least until you can afford something better. A cheap gun with bad glass is more fun than no gun and no glass!
Semper FI .... mark