I think i might have figured a trick that may save time and make reproducable results. Apologies if this isnt an original idea but i havent seen it posted anywhere before.
Ive watched a few youtube videos on checking what the theoretical maximum overall case length is by 3 methods;
1. Placing a projectile down in throat and measurind the distance from the crown to the tip, and then from the crown to the bolt face using a cleaning rod. The difference is the maximum cartridge overall length. I didnt like this method because my soft point projectiles usually have different base to tip lengths.
2. Using another expensive gauge. I’m saving for a 308.
3. Coating a projectile with permanent marker, placing in a case with the neck dented in a little, and then chambering the round. Basically where the case is scratches off the marker is the maximum length.
I found 3 the easiest, but found the results varied a bit. The projectile sometimes moves a bit when placing in the calipers. Building off that simple trick though, i figured instead of denting the case and using a marker, i would use a loosely neck sized case and add a small amount of 5 min epoxy well inside the neck and then chamber it with a projectile. So far,so good, as i haven’t glued a round into the rifle. Now i have dummy round which to use as my reference. If its done right, the projectile acts as a plunger on the epoxy, and there should be zero leakage. If the case neck is too tight though, the projectile will be forced into the lands too much to get an accurate set.
I’ve always found setting the seating depth on the seating die a PIA, so i’ve taken the dummy round and just screwed the adjustment until tip of the bullet is engaged with the die (i use basic lee dies). Next i epoxyed another projectile into a different case and then worked the die down to my nominal 20 thou jump.
Now whenever i want to make my usual load with the 20 thou jump, i can just put the second dummy round in the die and adjust the bullet seating mechanism down to that.