re the touch hole liners: You want the main charge powder as close as possible to the pan. The venturi description is great, but is mostly hot air. When loaded, you should be able to see granules of powder up against the interior of the touch hole and that should be almost to the exterior of the barrel flat. When the prime ignites, you want the shortest distance possible to the charge powder. It is a bit like grenades. the further away from the blast, the less damage. Now to some folks 1/16th or 3/32 of an inch is not that much difference in distance. But in the time it takes and the certainty of ignition, the closer the better. By time we are talking thousandths of a second. it it takes an extra 20 or 30 thousandths of a second, most shooters cannot hear the difference. But unless you have rock solid still follow through, the gun starts moving slightly with hammer fall. the quicker the ignition the less movement. Accuracy for match shooters comes from removing as many variables as possible. Careful powder measurement, measuring each ball to cull out those with voids. turning the patch the same direction each time, using the same thickness patch, the same lube etc. Why would a shooter create more distance than necessary between the prime and the main charge powder to create space for ignition time differences and barrel movement, however slight?