Had vowed to never respond to a thread with a title IN ALL CAPS, but can't help myself.
The Winchester-Western Mark 5 with a polyethylene shot collar (not wad) was introduced March 1962. These images are at 1/2,000,000 sec of the ejecta of a Mark 5 Super Trap load from a full choke M12. At 36" the ejecta with the collar does appear to have fewer fliers and a slightly shorter shot string
which was advertised as producing a 10% 'better' pattern
The Remington one piece 'Power Piston' polyethylene wad was introduced in 1963 for target loads. Some argued that roughening the choke segment would 'retard the wad' so it wouldn't run into the shot column. These images at 1/1,000,000 sec. clearly show the wad rapidly falling behind the shot column. Unfortunately, I couldn't fine the original reference.
SO
1. protecting the shot from abrasion/flattening is a good thing
2. air resistance adequately retards the wad.
And per Greener, polishing the bore may improve the pattern for
non-shot cup protected shot.
Please note: I freely concede that others here are brighter, better looking, have more valuable shotguns, and have killed more birds behind better dogs; therefore in responding please consider Proverbs 18:2 and try to be helpful.
