I went to the gun show in Tulsa years ago with friends. They all immediately found and bought a slide fire mechanism.
I took one look and thought..”This is crap!” and did not buy.
A few weeks later I asked them how their slide fire mechanism was working out and they all said... “It was piece of crap!”
If you own an AK with a downfolding stock, there is a homebrew bumpski rig that seems to work.
I wouldn’t go slidefire - just burns up ammo a lot faster. I watch some full auto vids on youtube & that satisfies the bumpski urge.