Boyd Allen
Active member
Some time back, I picked up a set of Hornady 6PPC dies, more out of curiosity than anything else. The FL die is a one piece, which was the point of the exercise. I wanted to see what its neck ID was, and how well the body part of the die fit my chamber. As it turned out, the neck ID was about .258 and the base of the body was a good fit, and it sized my fired case shoulders about .0025. I tried to "fix" the shoulder dimension by having someone who is known for polishing out dies to dimension do it, but that was a disaster. The runout of the cases from the modified die was way too much, and so I had paid to have a die turned into a paperweight. Not willing to give up on my idea, principally because before the modification case runout had been about a third of a thousandth, I eventually bought a duplicate die set, telling myself that I would have to live with the sizing at the shoulder. (As it turns out, that may turn out to be a good thing, rather than a flaw.) In any case, I came to the conclusion that for use with 133, which I believe "likes" more neck tension than the die's neck ID can produce, with necks turned for my desired loaded round clearance in a .262 neck chamber (.002 minimum) I set the die aside for use when I wanted to size to the shoulder before re-turning necks, and bumping the neck shoulder junction on turned .220 Russian cases so that they might chamber in my fireforming barrel with the desired fit. Some years later, I decided to have a barrel, that had gotten a little long in its throat for the bullets that I have the most of, set back, and in discussing the project with a friend, learned that he has a proven .263 neck JGS reamer. Figuring this would be the perfect setup to go with my Hornady die, I had him use that reamer to rechamber my barrel, and I have just finished turning some fresh brass for fire forming. The result (with 68 gr. Bergers) is .003 neck tension, and .002 total clearance from nominal chamber neck ID, which undoubtedly means that I have a tenth or so more. Tomorrow I plan on going to the range to fire form the brass and do some shooting with it. The point of the exercise was to produce the straightest sized brass that I can, that works well in my chamber. The JGS reamer is larger in the back than my old PT&D Boyer II, so I will be sizing more than I have been at the back, and I will be able to evaluate if this has any effect on accuracy by comparing results with what I get sizing with an old Harrell Vari-Base die with a base insert that only reduces fired cases (from this chamber) by .0005, using a .058 bushing. This old die does not size the shoulder diameter, so there will be a substantial difference in fit in the body of the chamber of ammo made with the two dies, given that the Hornady die sizes cases from the Boyer chambers .0005 at their bases. If looser shoots better, won't that be a wake up call? Over the years, I have written the specifications for a number of reamers, starting by buying a FL die, sizing some well used (with max. work hardening) fired brass, and adding to its dimensions the desired chamber clearances. While most of this has been done for top end field rifles, the results have been very good, enough so that I am seriously considering the same approach for a new 6PPC reamer. The one issue that I need to resolve before I do is the correctness of the assumptions about what sort of fit will produce the best accuracy. Perhaps this experiment will help with that determination. What have your experiences with 6PPCs been? Do you like the tightest possible body clearances, or do you get better results with more room?
