I picked up a dead chest freezer at the dump, filled it full of sawdust and water, stirred and tamped it around till it was firm. Tested a variety of calibers and loads. Some surprising results, .308, .303 and 7mm rem mag all performed well, the 174g HPBT out of the 303 doing surprisingly well with its core and cup minus petals going the same distance, 24" as the 7mm slug albeit the 7mm retained most of its weight. The .308 with 150g spritzers went around 22" with about 70% retention, the .308 with 165g SSTs did 17" with 98% retention and a noticeable wound channel. 7.62x39 with a Barnaul HP did a respectable 15" with decent expansion but lost the petals. 12 Gauge 7/8 ounce lee slug did 14" with about a 1" hole drilled to depth through the sawdust, and lost about 1/3 of its length but had 100% retention, the slug had been powder coated for fun and the paint had not even been completely removed from the nose by its passage through the two layers of sheet metal that make up the side of the freezer. The real eye opener was the .375 H&H mag. 270g performed very well with 80% retention and good penetration to 27" but my pet load of lee FP378-250 (designed for the 375 Winchester) powder coated and loaded on top of 13.5 grains of red dot went through the freezer like a bear trap in a bunny box. We only recovered one of the slugs from the 375, it had hit the compressor, bounced through housing, deflected up into the freezer and out the back but was stopped by the plywood catch board that was behind the freezer to show us bullet orientation of pass throughs. That slug retained almost all its weight and had slightly expanded but was mostly just a cylinder. The other cast 375s raised dust 150m-200m or so behind the freezer but skipped up kept on trucking