Al, I sure do appreciate you posting these topics lately. I am so sorry that the members of our chat forum are so unwilling to respond. They are all grown men and are too big and ugly for me to try to make them respond so I will tell you what little I know. My dasher barrel neck is .2704 and the outside diameter of a loaded round comes in about .268. I use a .266 neck bushing which gives me roughly .002 of tension. I do like to feel some resistance when I seat the bullet. I have often wondered if a very light tension would allow the seating depth to change with the loaded rounds bouncing around on the way to a match. I have also heard it mentioned that a properly annealed case is soft enough that a .264 bushing would not have any more tension than a .266 bushing but I have no way to prove it. If you have an annealing machine you might test the feel of different bushing and report back your findings. One other observation. This past month at the mid range match, I shot unfired .223 Lapua brass. While loading the rounds, I noticed that the tension was probably more than I would normally load and the thing seemed to shoot pretty well. Sorry for the rambling, maybe someone out there has some better test results. WWE

Al, Many bushing dies come with a button that works on the same principal as the mandrel you mentioned above. For some reason, all of that got a bad reputation as far as case concentricity. Supposedly the bushings straighten the case neck and on the up stroke the button bends the neck a little. As far as using the mandrel as the last step, most mandrels are very close to bullet size which would lead me to believe that you would end up with very little tension. Those with pleasant experiences should speak up and defend the process. WWE

Al & Wynne,

I have experimented slightly with neck bushings, in that I used a 267 bushing initially for the Dasher and found it was seating a little to easily for my tastes. I then went back to a 266 bushing and that made it better, this was with a 2704 chamber. I just purchased a Benchsource Annealer and must say it certainly makes resizing the brass much easier. We will see how it affects the group size.

DBB

In my opinion neck tension and OAL are the two most critical determinants of accuracy. The way Wynne describes is the standard that has been used for eons in b BR and FC. I do it a little differently.
I use Wilson dies. I purchased a K&M arbor press with force measurement gauge. I watch the gauge until the die bottoms out. I write the inch pounds it took to seat on the loaded round in magic marker. After all are loaded I sort them into the cartridge box lowest to highest. As I’m shooting, many times I can actually see as the POI slowly moves lower or higher shot to shot, depending on the wind and angle of departure.
My thinking has been that inch/lbs to seat = neck tension. Sorting them keeps a different tension from jumping out there on you.

Jim, you said above that neck tension and OAL are important to you. What exactly are you looking for? Am I right to assume that the type of bullets used could alter the results? Thanks, WWE