In my opinion, Browning BPS is your best choice...they're cast neutral, no palm swell, bottom eject, safety on top of the tang....
a model like the BPS Hunter ...sells new for around $ 600 in my area....and its a solid gun.
http://www.browning.com/products/cat...id=012&tid=211
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You might look around for some used ones....but they're hard to come by / most of us that have this model keep them around ( I've had mine since the late 70's I think, one in a 12ga, 28" and one in a 20ga 28"...I killed a lot of birds and clays with them ..and trained my 2 boys ...and several grandkids with them )....and since I have some grandkids that are lefties...its still good to have them around).
I don't think you'll find a better pump gun for the money than one of the BPS models...