Thanks for the memories.
When these came out,we had only Full choke guns around. We learned to use cheap old style loads for the first shot and these for followups.
This was pre lead ban and 6s were great for Ringnecks, Woodies and Teal. 4s were for Mallards, 8s for Quail and Dove.
Modern ammo is so much better than the stuff we used before the Mark 5 that I use an IC or LM choke instead of Full out to 35 yards.