So I did some more 410 shooting/testing. Since I was working hard to recover the wads as I shot them I had some interesting results with buck and even had some additional interesting results.
So with the buck the wad was getting slammed by the pressure wave and the buck was going through the bottom of the wad before it all got ejected. I see why some seemed OK while others were bloopers when I started looking at the wads.
In the pic below you on the left can see the wads blown apart and the base of the wad with the holes in them and how bad the wad gets mangled. I had some idea that that was happening (I wasn't tracking the wads and found some torn up afterwards). So I Loaded the same load with some cardboard wads (cut out of primer packaging) loaded under the wad for extra support and resistance from the powder burn. The two wads on the right are the result of that and as you can see it worked well. The loaded rounds also hit hard and there were no bloopers. Now I will get some real nitro wads and load my .410 buck loads from now on.
Since I was recovering wads I noticed something interesting with the wads from my normal shot loads. Looking at them it appears that there is quite a bit of payload setback when the shell is fired. If you look at the wads you can see the marks from the shot scoring the wads are only partially up the wad petals. When loaded the shot level is above the tops of the petal and that shows how much the shot setback when firing. Just something interesting I found and never realized.
The last interesting thing I found while checking wads was the wads from regular shot loads fired out of my 10" T/C Contender. It really shows how much the combusting powder slams the base of the wad. In normal length barrels the pressure is going down when the wad leaves the barrel and the base of the wad is normal (see pic above). What I found with the short T/C barrel was that the pressure must still be really high when the wad leaves the barrel because the blast "mushrooms" out the base of the wad as it leaves. This also shows how much pressure there is against the wad upon firing which makes sense when looking at the OO buck load wads with no card wads.