buying a 1924-25 flues. wanting to know about shooting buckshot #4 or 00 in reduced loads. Anybody who reloads? I want to keep the fps at about 1150-1200 with pressure at 6000 max. thanks a heap for any info. And yes the gun is tight shriker

Hi shriker. I own several Flues and contrary to what you may have found online, none of mine have cracked receivers. I shot RST shells exclusively in all my vintage shotguns so I'm not worried about the frames.
They do mostly have cracked stocks though. It is common that modern loads were put through the majority of them and either the top of the stock (both sides) behind the frame chipped off or the stock split vertically down the middle internally behind the frame. I have a 12 gauge Flues coming back from Dennis Smith, the Stock Doctor as we speak that was split. I'll post some pictures of the repair when it arrives next week.
So, bottom line, you are on the right track... watch the pressure and the speed and you will be fine. I only reload AA's for trap league so I can't help you with a recipe.