After further trial and error I found out if take the case and slip it over a taper punch you can squeeze the case where it fits snug on the nipple. Drop a few grains of BP into the case and press onto the nipple. The few grains that are in there will hover over the nipple opening with less being blown down the sides. I thought of this because of the tube lock video cap-n-ball put out on that tube lock. Along the same lines but it does work. Mind you my test rat was A Pedrosoli Leige Pistol. The distance is short in the Channel. So things may vary depending on what you want to try this on. Aside from the case not firing on the first try sometimes it does produce enough heat to ignite a small squib charge. Thanks for reading.
