Yikes, guys. This is too complicated.

WOW! $540 is a lot of money for a scope that fits your needs.

All will focus down to 25 yards (or much closer) and would work very well out to the end of the Ruger's abilities. My short list, by preference and price:

Weaver T-36 - Fixed power, good optics, in the $420 price range at www.swfa.com

Sigtron SII Target 36X42, $350 or so at www.whittakerguns.com

The Swift Premier 8-32X50 is pretty darn nice for $230 at www.eabco.com

Lastly, the Mueller Eradicator 8-25X50, right at $200 at www.eabco.com

Personally, I prefer a dot, fine cross hairs are getting tough for me to see and would lean towards a fixed power scope for (usually) superior brightness over variables. Would suggest the variable power scopes if you do any hunting with the Ruger, much easier to get on target at lower powers.

With a good 36x scope, you get to see the grain in the paper at 25 yards. Yes, they really do focus in that well. Does take some discipline to get onto the target because the field of view is pretty small.

Weaver and Sightron both make a 24X and for target shooting at 100 yards, you'd probably not want anything much below that.

One of the best variables that fit your criteria under 30X is probably the Bushnell 6-24x40 Elite 4200. They're about $450 and might be a good compromise if you're unsure of committing to a high power fixed scope. Like the Burris you'd already pointed out, it's a very good scope. I'd avoided both since you'd mentioned only shooting targets. I'd lay odds you'll set the magnification once, and leave it so way pay for features you're unlikely to use?

For you and your Ruger, think I'd look to the Sighton target in 24X for a fixed, or probably the Mueller for a variable, but I think I keep an eye on budget a bit closer than you.

Still, hope I've at least helped to narrow the field down a bit for you, or at least give you more food for thought.

With your budget, there are a lot of very good scopes out there, it's finding ones that will go down to 25 yards that's the issue. I've a great Nikon that's available under your budget, but 25 yards taint happening with it. Leupold does some really nice EFR scopes that'll do 25 yards, but they bust the buget if you want enough magnification for 100 yards and many/most? of the Leupold are like the Nikon, and are more of a 35-50 yard minimum.

Good luck!

The Burris your looking at doesn't just fail to do well below 50 yards. 50 yards is pretty much a hard limit to how close it will focus for you. That isn't what you want.

This is more like it
http://theopticzone.com/searchresult.aspx?CategoryID=42

Bushnell Elite 4200 6-24x with target dot etc. etc. There is little difference in the optical quality of this and the Burris. And this one is useful down to 10 yards. $379

As for the dot or plex, well depends on your use. Dot will be useful only for targets or maybe varmints in bright sunlight. Dots are not the ticket for hunting in general.

I agree with the previous poster in that most likely you will end up with it on 24x and leave it. So a fixed 24x would be more efficient. But the Elite 4200 is such a well done scope you really aren't giving up much with the variable. And it gives you options for other unanticipated uses. Also is available in a nice mil-dot version.

But this is a high quality great scope which when combined with the AO to 10 yards makes it close to ideal for high power magnification on a rimfire.

i just purchased a new bushnell elite 4200 8-32x40mm AO and it is awesome. it comes with two types of target turrets, sunshade and lens covers. all for under $395.00. in my opinion it puts everything else in the shade other than leupolds and high end european models. it will dial down to 10 yards, advertised 95% or greater light gathering, full multicoating lens, 1/8" clicks, solid sturdy one piece construction, great warranty, etc.
i have a sightron, swift, nikon and bushnell scopechief on my other rifles for comparison.
if you are interested go to e-bay and look for the "hunting" category than look for "scopes, lasers and optics". do a search for "elite 4200" and check out the listings of the 6-24x40mm or 8-32x40mm. either one is available new for under $400.00
in my experience when you go above 15x or so many of the affordable or medium priced scopes get a little dim to see thru, but the elite stays clear right up to the top
as i stated earlier this is my opinion based on my experience, but the elite 4200 stands up very well in comparisons to leupolds on other forums and is worth serious investigation