Fiber wads are a wonderful bio-degradable alternative. They will cushion and trap the gases from the powder, provide a cushion for the shot, and then degrade into invisibility in a few weeks. Unlike those nasty plastic cups I find all over. What they won't do is hold your pattern together so that your vintage improved cylinder double suddenly patterns like a tack driver. It will pattern like an improved cylinder, might get a few more flyers. They will not cushion the barrel walls with steel shot, and damage over time will occur. Other issue, but should not be a problem in modern factory loads, Old timers who reloaded, mostly trap shooters, and others who reloaded a lot prior to the modern presses which put out a high standardized load, would ocassionally pop a cap on a load where the wad stuck in the barrel, not an issue, unless undiscovered prior to the next load being fired. Result usually a bulge in the barrel, or a burst. You find vintage doubles and single trap guns all the time with bulges, also accounts for the majority of sawed off doubles on the market! I use them all the time in my doubles with 2" and 2 1/2 " shells, I use RST and Polywad factory, and I handload, ( literally), brass shells. when using the brass reloads, I always take a look down the barrels between loads. With the Kent loads, RST, Polywad, I wouldn't give it a second thought.