M305 AND Mini-14 Catcher
I did the following...works great, catches all M305 and about 95% of Mini-14 brass.
I bought a cheap 2' x 3' square basin (at least 6" deep, a 12" bar clamp, about 1 yard of the heavy tent canvas, a 6' 5/8 dowel and a 3' long 3/4" dowel rod.
The tub is fastened to the shooting table (at an angle because the tub open end is always larger than the bottom. When set upright on a table, it will sit at the angle due to this geometry.
Cut the dowel to match the width of the short side of the tub (just under the lip. If the dowel is too big, then substitute with a piece of cut plywood. The idea is to reinforce the lip area along the length of the (short) side. Next, cut a hole near the top so that the clamp (top jaw) can be inserted and set to grip on the lip/dowel section.
Cut the canvas to generally match the open end of the basin, less about 1" on the sides (narrow sides). Add approximately 2" of extra material at the top and bottom. Take the 3/4" dowel and cut to match the short side of the canvas. This will be your weight. Roll the canvas (about one whole turn) and staple (or nail if that suits you) to the dowel. Take the remaining 5/8" dowel and cut to mat the top of the canvas. As with the bottom, roll the canvas on the dowel (approximately 3/4 turn) and staple. Next, insert the top dowel behind the lip of the tub, and make sure the canvas is in front. When laid flat, the bottom dowel should rest near the bottom of the tub, it should be free to swing freely, but not too much. With some 5/8" wood screws, fasten the canvas, lip of tub and dowel together. Depending on the style of tub, longer screws may be necessary.
Voila!....You go out to the range, fasten the case catcher to the table with the middle of the canvas/tub at the center of the bolt. The canvas will absorb the energy of the flying case and let it drop to the bottom of the tub. When shooting the mini-14, your neighbour will appreciate not getting a hot case in the forehead. It will catch all of your M305 casing if shooting near the catcher.
Gene