case shoulder requires a custom extra- tall Competition shell holder. To suit the needs of some customers Redding has made such shellholders as much as 30/1000-inch taller than standard.) LIMITATIONS
Even when using the ideal Com- petition shellholder for any given die and gun, variations in case springiness, die body stretching, case lubrication, and handloader technique will gen- erate some headspace variation. My experience suggests that when resiz- ing quality cases from the same lot and with the same usage history and when using a consistent technique and uniform lubrication, this variation is less than 1/1000-inch. As noted, when you full-length resize your cases and the shellholder does not solidly abut the base of the die you can be sure that case-to-case headspace variation will be much greater than 1/1000-inch. COMPARATIVE EXPERIMENTS: TEST #1
I collected a reasonable selection of once-fired commercial and military 30- 06 Springfield cases by sorting through
the stash of my late friend, Roger Hazle- wood. These included three nickel- plated cases and four military cases. In addition, I selected five once- fired 270 Winchester cases from the same-lot to give a good comparison of the variation that we might expect among same-lot cases. Because the necks on these cases will not touch the neck- ing portion of the 30-06 sizing die, this test compares only the effort required to resize the case body and to just begin to move the case shoulder. I cleaned all these cases in a vibra- tory tumbler using corncob media with a polishing agent added. I then washed the cases, to assure removal of all dust and debris.
I carefully lubricated each case
as uniformly as I could using Sharp ShootR Royal Case Lube. This is the best product I have yet tested with regard to reducing the force needed to resize cases. (As a bonus, Royal Case Lube smells good and is non-toxic.) Then, I removed the decapping rod and neck-expanding assembly from my standard 30-06 full-length sizing
TEST #1 Case Resizing Comparison Study Random Range 30-06 Springfi eld
Case Make Stress Gap Comments (1/1000-Inch) 12 11 11 10 9
F-C
R-P 1 R-P 2 Win 1 Win 2 Win 3 Win 4 Win 5 Win 6
I would not expect to see such uniformity within a larger sample
10 9
12 11
Super-X 11 Mil-HXP71 Mil-TW 54
9 9
Mil-TW 54 11
Notes: The following factors would progressively increase the differential case-dependent gap between shellholder and die (and therefore functional headspace variation of resized cases): • Less rigid press;
• Less uniform lubrication; • Less effective lubricant; • Sharper or wider case shoulder; • Larger or otherwise tougher cases; and, • Less uniform operation of the press. Under the testing protocol that I followed, measured case-to-case stress-gap variations are about as small as we could expect to see with 30-06 family cases. (With any given tools, lubricant, and technique, conventional belted magnum cases would generate about 50% greater variation, the new fat magnum cases would give about 75% greater variation, and the largest of typical modern hunting cases would give twice as much variation.)
www.varminthunter.org Page 137
Nickel plated Nickel plated
Newer nickel plated
Same-lot Frontier 270 Winchester Case
Stress Gap
1 2 3 4 5
(1/1000-Inch) 9
10 9
10 11
die and installed that die in my Red- ding Ultra-Mag press. I adjusted that die so that the fully raised shellholder just touched the base of the die. I used a Lee locking ring system with the lock- ing nut tightened sufficiently to assure that o-ring compression would hold the threads of the die body fully up against the threads in the press.
I then raised each prepared case fully into the press using as nearly uniform technique as I could muster. With each case in place at the top of the
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