In my earlier post, I failed to mention the wads I use. I think this is important as there are many possible combinations. My initial turkey loads in the .62 fusil de chasse were with standard 20 gauge nitro card wads and lead shot. We live in a very dry region and this spring we are in the 4th year of a serious drought. I believe Art Fleener on this forum questioned the risk of wads starting fires and this has been a concern for me since 2016 when I obtained this gun. For turkeys I have been using 2 UNLUBED hard wool felt wads 1/8" thick that I cut from material purchased from DuroFelt under a 20 ga. plastic shot cup from Ballistic Products Inc. This one is from their CSD series and is not slit. I slit them with 4 short slits of about 3/8". I have learned that these are intended for steel and other hard shot and they are thick tough plastic. If you look for opinions about slitting this type of wad on the internet you find many. No surprise here. There are people who insist that if not slit, these wads will sometimes, if not frequently, fail to separate from the shot column and act as a potentially dangerous "slug". I have fired many patterns on paper with these wads slit to 3/8" in 4 equally spaced cuts and I have never seen slugging. I initially tried a few with no slits and in at a least one instance, I did see slugging at 30 yards distance. I do not use them unslit and I believe that if people use them they should be aware of that possibility.
I cannot give a figure as to what percentage increase in pellet density these wads give in this gun over card wads with no shot cup (cylinder bored gun). However, it was very noticable in my trials. I did most of my pattern testing at 30 yards and at that distance got 85-88% of a one ounce load of #6 shot in a 30" circle. According to the work cited in Oberfell and Thompson's book (The Mysteries of Shotgun Patterns, 1957) and in the three article series by Kevin Tinney and Philip Orem published in Muzzle Blasts in Aug., Sept., and Oct. of 1987, this should equate to a modified or improved modified choke. Similar information is in an excellent article titled "Pattern Analysis for Busy Sportsmen" by Ron Jones in Shotgun Sports magazine in March of 2013 I believe. I have posted two targets from my testing; one fired at 30 yards and one at 25 yards. I limit my shots at turkeys to 25 yards with this gun and it has been effective. I want to try some patterns without the shot cup and with hard #71/2 shot. There are about 225 #6 pellets in a one ounce load but about 350 in one ounce of #71/2. I strongly suspicion that there is enough remaining pellet energy in #71/2 lead shot at 25 yards to penetrate the head and neck bones of a turkey, and the increased number of pellets (almost 50%) would be a significant advantage. For rabbits and pheasants, I do not use the shot cup and use 3 wool wads or one wool over the powder and a nitro card over the wool and under the shot load.
Wool is an amazing fiber. Of interest to me in this application is the fact that while it can be burned, it does not support combustion - meaning when you take the heat source away, it stops burning. In the other picture you can see the plastic wads and some fired wool wads that I have recovered from pattern testing. The plastic is not badly distorted and the wool wad next to the powder is badly frayed and scorched, but the wool wad next to the bottom of the shot cup could almost be used again. The plastic wad on the left is a new one. I recently acquired some 20 gauge 3/8" thick wool felt wads from Precision Reloading. These are meant for filler wads and seem to be high quality wool as observed from trying to burn them with a propane torch. They are not hard, dense material, but they may work very well. I hope to try more of them. The load in the 14 gauge John Mullin gun I used for the turkey killed last November was two 1/8" wool felt wads over the powder and then a 1/8" nitro card then the bismuth shot and a thin card over the shot.