You can interchange nails with different guns. I have no problem doing this with my finish guns. But, I have had a lot of jamming with my framing gun. To be on the safe side I stick with what the manf. reccomends. Hope I could be of some help.
I have two brad nailers. For the one brand, I needed longer brads and could not find the brand that I needed. I talked to the saleperson in the construction department of the hardware store and he said if the color of the heads were the same that they were interchangeable. I bought the longer ones that he recommended and they worked. I don't know if this is always true or that if I was lucky. fwiw.