OK, I just ran a penetration similar to the one Gohon ran with one gallon water jugs. If you remember Gohon's results: the 129 gn hydra shock, the 158 gn LSWCHP and the other 158 gn lead slug all penetrated 4 one gallon jugs and all stopped against the back wall of the fourth jug.
Gohon used one gallon plastic milk jugs and wrapped them with duct tape to keep the whole kit and kaboodle together. I did the same but I gotta tellya it takes me a looooong time to drink 6 gallons of milk..........
Anyhow - filled all six gallon jugs, screwed the tops back on, taped the whole bunch together with a couple of lengths of duct tape, backed up 10' (defensive distance) and fired one round. Once the jugs start leakin' they hain't no good for a follow-up shot.....
The load was a 200 gn cast semi-wadcutter over 3.8 gns of WW231, a factory load for the 200 gn bullet. Velocity is listed at 770'/sec but from my M38 (2" snubbie) I doubt it's passin' 700'/sec by much, if at all.
The bullet hit dead on the mark and penetrated clean through all six gallon jugs, and kept on going. The first two jugs came apart at the inside handle seam - jug side, the third jug suffered a inside handle seam -jug side split, the fourth and fifth jugs had a couple of small holes in them and the 6th jug just had the pass-through. All the screw caps remained in place.
Each one gallon jug measured 6" square at the bottom 1/2 and that's where the bullet penetrated - right through the lower portion of the Skim Milk label and the thickest part of the jugs. The bullet penetrated straight through, exiting the back of the 6th jug at the same height of the bullet entrance through the 1st jug. The table they were placed on was level.
So, all in all, this one 38 Special 200 gn cast semi-wadcutter slug at probably only 700'/sec, passed clean through 3' of water (3 feet of water jugs that is), 12 plastic jug skins, two layers of duct tape, and kept on goin'.......
Good enough for me. Mikey.