I am trying to remove the breech bolt on a Beretta Extrema. I am having difficulty removing the piece holding the assembly in place. I think it is supposed to simply pull out like the one on the 391, but I don't have a manual for this one. Any ideas? Online manual?

Take the barrel & forend off. That will remove the spring tension on the bolt. Now look closely into the slot that the operating handle fits into. When moving the bolt head fore & aft ( the bolt head will be caming ) you will see a point at which the operating handle can be pulled out. Once you do it once it will become a piece of cake from then on. Hope that this helps.