Don't know if this is the right place. Years ago I read an article about some one who was casting boolits for a 375 H&H but he would put short pieces of copper pipe in the driving bands so that they would bear on the rifleing and he could load to faster muzzel speeds.
1) Has anyone tried this ?
2) If this works, then what about using 1/4 in ID soft copper for an OD of .3125 to be used in .303 7.7 jap 7.62x 39 ect.?