Ak-Builder Rivet Tool
This is the tool I use too secure the rivets. It is based on Plinkers jig.
The problem with the riveting is not forming them, it is securing them from behind, inside the receiver.
Back in the early days, everything was tried, until Plinker came out with his concept.
For the long rivets that go all the way through the rear trunnion.
You can cut off a ratchet handle, bowl it out too rivet size, support with a "rivet size cup" on the opposing side and form your rivet.
Certain tools are a time saver in this process.
Other builders may have other ideas. But I went though hell trying too support the rivets from behind, until I purchased the riveting tool from AK Builder.