A trip to the nuts and bolts drawer yielded some 5/16" counter sunk head bolts. With these in hand, I drilled the necessary holes in the angle iron and plywood. Since I don't have any countersink drill bits, I managed to countersink the plywood holes by gently using a 9/16" drill bit. It worked just fine. Nyloc nuts were used to secure the bolts. It's not likely any will vibrate loose in the foreseeable future.
Here is the finished shooting bench fully assembled with nothing bought from the local home center. As built, it is too tall for a typical chair. However, it is the perfect height for leaning onto the table to shoot. I know this for a fact since my nephew and myself both shot this way and experience no problems. Since we were sighting in a .300 Win Mag, we used my nephew's Lead Sled. It and the shooting bench made a great combination.
The stump grinder company built the lower base with flat stock for reinforcement. As it sits, it would provide storage space for almost anything such as sand bags, ammo cans, etc. This would quickly add to the 50 pound current weight. For about $30, I can get four replacement lawn mower style wheels. Mounting these on a couple of properly sized metal rods would allow the bench to be quite portable unless the terrain being traversed was too much for the wheels to navigate. Not sure if I'll pursue this option....but having an option is always a good thing.
Speaking of options, another possibility to make this bench very portable, for true in-field use, is to make a simple 3 point hitch so it can be attached to the back of a tractor. This may be a bit of overkill though because I could also just strap it into my tractor's front-end loader for transport out to the field. Our last shooting session was done from the back yard but that limits us to about 200 yds wherein we can go out to 400+ yds if shoot in the field.
So there you have it....a do-it-yourself shooting completely made from repurposed/scrap material. I realize it is not likely that you'll buy a Woodland Mills stump grinder in order to get their metal shipping crate. However, hopefully this write-up might provide you with some ideas for how you may be able to do the same thing. Here on the homestead, we try to find alternate uses for things with this being a good example. I hope you can too!
4x4 Off-Road Homestead Firearms RC Flying