sabotloader

Well, i guess it is a good thing the 25/64 drill will work, because it doesn't appear that a 40* end mill is readily available. Seems to me that it would be best if the rim of the vent liner made first contact with the breech plug. Like you say, i can make that happen by grinding the drill to a steeper angle than 30*. Seems that if the angle were ground too steep, it would be better than if it were too shallow.

I guess i will start the modification before the vent liners arrive, by drilling out the fire channel with a 5/32 drill, then when i have the vent liner in hand i can drill again, and through with a #21 drill. Doesn't seem as though it will be much of a problem. Time will tell.