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MYLAR WRAPS

Q. I recently started handloading shotshells, and have come across some load recipes that call for "Mylar wraps." What exactly are these components, what do they do, and are they necessary? — Stephen Weatherholt, Dalton, GA

A. A wrap is a small square of Mylar material that you roll into a cylinder and insert into the shotcup of a wad. By allowing the Mylar cylinder to unroll against the cup walls prior to filling the cup with shot, the wrap provides a strong but thin barrier between the shot and the walls of the shotcup.

Before high-velocity steel shot was commercially available, I used to load my own. The recipe I used moved the shot at about 1500 fps, and called for Mylar wraps to keep the steel pellets from possibly slipping through the shotcup slits, or scrubbing through the plastic wad, which would possibly damage the bore or choke of my shotgun. When a Mylar wrap is used in conjunction with a thin Tyvek overshot card, it helps keep shot pellets contained within the shotcup as it passes down the bore, and all but eliminates the possibility of damage caused by a pellet migrating out of the cup.

My experience is that neither the wrap nor the Tyvek overshot card has a negative effect on shot patterns. My recovered wraps never showed that a pellet had scrubbed through. I've only seen the wraps called for on very high-performance steel shot loads, though I could see them as useful in some tungsten-iron or HeviShot handloads. As to if they are necessary or not, if a load calls for them, then use them, if it doesn't, don't use them.