Originally Posted by
dicehorn
It is usually suggested that the diameter of the bullets seated in the neck is a good starting point ie 308 should be at least 308 thou in the case or better still start at the recommended COL of 2.800 as in your 308 using the OCW or Satterlee method to test.
Personally I have never been able to get my head around the concept of seating the bullet 20 thou or less unless it happens to be a bench rest rifle. Most rifles have as many as four sweet spots, granted the first may well be less than 40 thou but that may be the obvious node to find - against it are two points to consider - will it fit the magazine and now with this long bullet balancing at the end of the case neck you are creating quite an air gap above the powder which can delay ignition by a nano second especially as that air pocket will creep back towards the primer as usually rounds are fired on the horizontal.
I must confess to having a little chuckle when you mentioned 'a massive 175 thou jump' - a chuckle only because my 20 Tac with a custom barrel is 223 back and will group sub .2, my 22.250 at 220 thou and 6.5 at 180 thou - both well less than .5"
Tried to put a couple of scans of other people's rifles I reload for showing these 'massive jumps' but I'm not technical enough to achieve this.
Peter
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