We've found a hole drilled through the material and hung with a clevis and chain to be the best way to present the targets.
I have found the same thing. Here are two targets with frames made of 1/2" round stock that is just pressed into the ground.
The smaller frame is probably 20 years old that originally had a 7" dia disc suspended by a welded bar. The weld recently broke, so I am reworking the frame to use replaceable targets suspended on 3/8" chain attached to the frame with clevises.
The original target, on the smaller frame, has taken untold numbers of hits, including probably over 250 hits a weekend at several club sponsored rendezvous, so the smallish frame has held up well.
The larger frame is new, as is the buffalo target. They are about ready for use, other than welding a coupla heavy ga, non plated washers on either side of the top frame, to prevent the targets from walking with repeated hits.
The good thing about this set up is that it is man portable, targets are easily changed/repaired, convenient storage, and cheap and easy to build.
God bless
God bless