holy old thread, batman!
The 3 biggest thumpers I own, in order, are:
500 A-square hannibal. ~12lbs or so, no brake. 600 grainer at 2600fps
378 weatherby, BRNO zk602. ~11lbs, magnaported. 300 grainer at 3000 fps
45-70 H&R buffalo classic. ~ 8lbs. 400 grainer at 2000 fps
Then the little stuff like 338's and 12 gauges. I'm still missing a 416 rigby from my collection, and if I knew I could find a decent supply of 14.5mm bullets I'd consider having a no. 1 chambered in 577 nitro, 585 nyati or 577 tyranno