Anyone know anything about this type of round?
I found an upper for sale .
Is it worth buying?
Can this round be bought at the Local  Store?
I know nothing about it and have never heard of it before.
Am I better going with the 6.8?
Just a Few questions...
Thanks for any info...

dont know about your other questions, but yes you can buy it at the store (its not rare if thats what you mean)

I have 243WSSM BOLT GUN...its a good bullet....REALLY, accurate. I t put the bullet in the hole I aimed at with not so great scope... the bullet family is good

The .25 WSSM is a great caliber.  You can find the loaded ammo at Wal-Mart and most sporting goods stores.  The .25 WSSM upper will fit on a standard, un-modified AR-15 lower.  It takes a modified AR-15 magazine (a 20 round AR mag gives you a capacity of 7 WSSM rounds)

I am getting 25-06 velocities out of a 22" upper with great accuracy and excellent feed and function.  Where you get the most energy out of the .25 WSSM, a couple of the factory loads are too long for the magazine.  All of the factory offerings for the .243 WSSM fit in the modified AR mag.

Here's some more info. I was interested in the same upper.  As I understand it the 25 wssm is a bit longer and doesn't fit well in the ar 15 mags.  Some say you have to reload and seat the bullet a bit deeper.  I really like the ballistics of the 25 wssm and would love to get an upper that worked well.
www.ar15.com/forums/topic.html?b=3&f=118&t=267568

The 120 grain factory loads are about .015" of an inch too long for the magazines I use.  I have seen some mags that they will fit, but I don't have a place to procure those mags.  

The factory offerings above the 110 grain will need to be seated back to fit my magazines.  The 110 grain and the 85 grain will fit without seating them back.