Here's a photo of my .404 which is on a Brno 602 as well. Mine was also a .375 H&H which was in pretty bad condition when I got it. The action is a single square bridge and is totally devoid of any markings etc, I've never seen another one like it. The barrel on this rifle is 24" and has a muzzle diameter of just under .750". If I was doing it again I would go for a lighter weight barrel as this rifle all up weighs over 11lb, which is up around my .500 doubles weight. It doesn't need to be this heavy and after a long day carrying it around you get to feel every ounce of it. I think it is also a little front heavy so a lighter barrel might help here a little as well.
If the photos have downloaded properly you'll see the effectiveness of the .404. The chopped down tree was the second shot and it still hit the buff. How I didn't see that tree from 30 yards is beyond me

I like the .404 Jeffery it is a very effective cartridge on Buffalo and tips them over with ease.