After a couple of decades trying to figure out the truths behind neck tension and accuracy, have found that for the most part, I've been shooting at a moving target. IMHO, it's not a cut and dried proposition.
Every strategy I've tried can be defeated by things like work hardening, age hardening, bonding, and probably other factors Ive never even considered. No matter how hard I've tried to ensure uniform case attributes, I still believe that no case is truly identical to the one that precedes it and the one that follows it in the reloading sequence.
Perhaps this, more than any other factor, negates a lot of the more delicate accuracy stratagems. I have returned to SAAMI chambers and dies in the potential belief that a lot of these strategies work at odds with each other, possibly negating the effort and introducing higher complexities to what should probably be a more mundane and expedient process. The more things you do, the more potential inconsistencies you must face up to. I believe that by settling for some small degree of inaccuracy, the majority of the fewer truly necessary steps do the real heavy lifting where accuracy is concerned, and that additional effort could really be more usefully employed in concentrating more on marksmanship basics.
When we think we have every factor under control, what we may be doing is blindly ignoring those factors that are beyond our abilities to quantify, and therefore control in making our ammunition, I suspect there are a lot more we can't control then those we sincerely believe we can. At some point, the laws of diminishing returns apply; and we don't shoot much of the ammo because we spend so much time making it.
I use competition to test whether this simplification process can still produce acceptable accuracy, with winning being set aside and the real payoff coming in finding how close one can get to the products of other's all out intensive pursuit of accuracy at all costs. I don't win, but then, I'm not trying to, my goals are simpler. I shoot for enjoyment, and when I shoot better, I enjoy it more.
Some, maybe a lot of people, don't see any benefit to this approach. That's OK, they have their own goals, and mine really shouldn't threaten theirs at all. As I said, I've competed for several decades. As I approach 70, I'm turning down the wick a little, stopping to smell the spent gunpowder on the morning air.
A few things stand out regarding neck tension.
A certain minimal neck tension is required in order to achieve consistent ignition.
My testing mildly suggests that more tension than what is needed above might not be beneficial to accuracy; understanding that I was doing single feeding in a bolt gun for this testing. It appears to me that making a cartridge stand up to the various mechanical insults we inflict on it may require more neck tension than can be necessary to gain best accuracy.
If the bullet can be turned in the neck with thumb and forefinger, neck tension must be increased until it can't. Any round that resides in a magazine during firing needs even more neck tension to prevent setback.
There is more than one way to adjust neck tension, including partial length neck resizing.
now there's a thought: internet forum as cheap entertainment. :
