I do not have any sophisticated equipment for determining how to load a round a set distance off the lands. The method I have used is to size a case mouth to have a snug slip fit on the projectile, set the round well beyond expected OAL and chamber the round. I will do this several times to get a good feel for the resistance and come up with a consistent average dimension.
I rely on the contact with the rifling to seat the bullet to depth, understanding that it is likley already into the lands a couple thou. I assume this interference and deduct maybe .002 as an assumed zero jump/in contact round.
Can anyone recommend any enhancements to this method to assure precision? I have tried blueing the bullet afterward to see if there are signs of contact on a round that should be .002 to .005 off the lands and do not see any marking from contact, but I am not really sure if this is telling me anything.
I appreciate any insights anyone has or any tricks for determining this.
FYI the current rifle in question is a 338 LM and I use a Comparator to eliminate the variability of mis-shapen or damaged projectile tips.
I rely on the contact with the rifling to seat the bullet to depth, understanding that it is likley already into the lands a couple thou. I assume this interference and deduct maybe .002 as an assumed zero jump/in contact round.
Can anyone recommend any enhancements to this method to assure precision? I have tried blueing the bullet afterward to see if there are signs of contact on a round that should be .002 to .005 off the lands and do not see any marking from contact, but I am not really sure if this is telling me anything.
I appreciate any insights anyone has or any tricks for determining this.
FYI the current rifle in question is a 338 LM and I use a Comparator to eliminate the variability of mis-shapen or damaged projectile tips.