My Beretta White Onyx Sporter is a trifle ponderous for dove, but I have used it with 7/8 oz loads with decent results. Since I obtained an Ithaca/SKB 20 gauge O/U last year, I plan on using that instead.
IIRC, I used Trap grade 7/8 oz loads of 7.5 shot at 1200 FPS through LM and Mod chokes. If I hit them they were dead before impact....