Here's what I did yesterday, it has over 800 lbs of concrete. There is also ALOT of rocks. my guess is it is at least 1000lbs.
geek is right, they are for tools.
May that's a disappointment. I thought that they were for rocket launchers.
Mars
I know this is an old thread, but I'm considering doing a similar build, and I'm wondering how you attached your lower link pins. Did you just stick them in and let the concrete set around them? How has that held up? Have they pulled out or anything like that? I have seen a lot of other folks stick a drawbar through the barrel. This solution seems neater and cheaper, but I'm wondering if it is sturdy enough.
Shoot, the OP appears to be gone. Dang it.
I'm questioning the "1000 lbs" in a 30 gallon drum, though. Unless there's some collapsed star material included, I don't think it'd reach that weight.