Take the longest bullet you plan on shooting and seat it to have the boat-tail/bearing surface junction just ABOVE the neck/shoulder junction. I would not get that junction past the neck.
Hey Grant. I think Robin just said what we were talking about on the phone last night. From the boattail end the bearing surface should be just ABOVE the neck/shoulder junction of the brass. With that setting when you develop your load, it leaves a little room to seat the bullet a little deeper if you need to jump the ogive 10-40K to the lands.
That’s the advantage of getting the chamber custom reamed - you optimize the chamber throat for the specific bullet you want to shoot.
Incipient head separation WITHOUT other pressure signs is usually not due to an over charge of the cases with only four reloadings.. It is frequently due to an excessive shoulder bump during resizing which leads to major stress on the case wall every time the case is fireformed into the chamber.
There we go again Dave :-) typing the same thing at the same time!
Dave I don't need to tell you that your technique is as accurate as you can get. The advantage of the thrower and the trickler is literally just setting there and watch it all done automatically in 1/4 the time. The stress relief of not having to sit there and focus on every step makes them financially worthwhile. I think I sold Danbozo with one statement - " it makes reloading fun again".
This all started about a year ago with me getting Danbozo and rardoin interested in the Sartorius/Fx-120 followed by a hard sell on the autotricker even before the autothrow was available. Man I think I should be gettin a commission!!!!!!!
I am guessing you have a level on this scope. You describe loading the bipod and gently controlling the grip with your trigger hand. During the process of loading the bipod chances are good that you are getting a variable cant on the stock and a variable amount of recoil management. If you are finding that sometimes you can follow your shot in the scope during recoil and sometimes you can not, pay a little closer attention to preventing the rifle canting and more consistent recoil management even if you have to snug the stock into your shoulder a little more forcefully.
Going from benchrest shooting to prone several years ago, this was a problem I had to consciously control until it became second nature. Even today I will peek at my level and find I’m just a little off. Typically a slight cant at 100 yards is no big deal as far as bullet trajectory but it does indicate inconsistent recoil management.
Sounds like you found a good inexpensive solution. I am also near sighted but can still adequately focus for pistol sights. The sight length between the rear and front rifle sights are what creates difficulty for me. My solution there is to go to a scope with reticle focus adjustment.