The part that doesn't make sense to me is why bother with a bushing when using a mandrel. One would immediately follow up with overworking the brass and the then one would question how that is possible if perfectly annealing with a 2000 dollar machine every time... I say start with the standard dies, add mandrels and see if something more is needed. Could the op even see results from the first change.... the ability of tuning neck tension is a big step by itself....
You’re missing a lot in the application of these practices here.
Yes, if you use a grossly undersized standard die, not a bushing die with a carefully selected neck diameter, you are overworking your brass. Why would you want to go through the trouble of annealing just to throw back excessive work hardening during the sizing and expanding steps?
The more you move the neck, the more you invite induced error and variabilities.
Moving the neck too far - without purpose - does mean you are more likely to need to use an oversized mandrel (relatively) because the now grossly undersized brass will spring back more (yes, even after annealing, because you somewhat work hardened the brass again during the sizing step AND because we aren’t softening brass via annealing to the point that it would be as weak as wet toilet paper…). So again, the more you move the brass, the greater our proportionate error becomes in magnitude. 10% of 2thou is .2 thou variability. 10% of 7 thou is .7 thou, more than 3x that of the former… you can directly feel this when you use these tools in application. When I use properly matched dimension bushings and mandrels, there’s only a slight drag sensation on the mandrel, and dipping again will have far less sensation, dipping a third time has only a slip fit sensation. When using a standard die which are always grossly undersized, it make take 3-4 dips with the mandrel just to get the brass to come back to the proper inside diameter (the ENTIRE purpose of the mandrel), which means I’m work hardening that brass more and more… all because you don’t want to buy a few $19 bushings…
Equally, we are really “tuning neck tension” with the bushings as much as we are the mandrels. We CAN set neck tension with bushings alone. The mandrels just help in dressing the interior contact surface, and moving brass in both directions helps ensure any inconsistency between brass is better brought to uniformity - think about aligning a stack of notebook paper, we stand it on end, tap the sides together, tap it on the desk, and tap on the top edge, moving paper in all 4 directions to coalign the stack.
Will using a standard die, without the expander button, combined with a mandrel expander perform better than just a standard die? Absolutely. Using a standard die which has had its neck honed to better match the rifle chamber will also perform better than just a standard die. Using a bushing die with a properly sized neck bushing will also perform better than a standard die. We’re not setting the bar very high by just comparing to standard dies with expander buttons. But moving the brass ONLY as far as necessary and producing an intentional and consistent neck tension will out perform excessive brass movement and variable neck tension - so why ignore the advantages of moving the brass less to promote more consistent neck tension?
