[Unclenick]

Originally Posted by GWS

I agree with most of that, except that I felt the non-rotated steps slowed me down because I could get to .001 without them if I just rotated immediately.

Did you test it the same way? It looked to me from the plot like two more unrotated sizing steps would have landed you in the same place the last two rotated ones did. That's why I suggested rotating didn't look like it was getting you anything. But if you think you can get faster results with rotating, that's easy to verify. Just find five cases with close to the same average pre-sizing runout you started with in the last test and use the rotating exclusively and see what happens by step 6. If the improvement has flat lined before you get there, that's your proof.

Yes, you can use cases as your slug. It's them you want to resize, ultimately, anyway, so they are the acid test. It's just that you have to stop and clean the die completely, put it in a press and then put a few lubed cases through it to check. With the gauge you just withdraw the hone and push a cleaning patch or two through to clear loose grit and oil and then measure with the gauge or tap a pure lead slug through. Repeat until you are half way to what you expect your minimum amount of neck opening up to be. A that point, clean the die and check by sizing a few cases. Repeat. That's an old machinist's trick, taking off only half the metal you think you need to remove at a time. It prevents overshooting the mark, which matters as you can't put metal back on very conveniently.

You can get a 0.3125"-0.500" telescoping small hole transfer gauge for just under $12 at Enco. They also have a full set, 0.125"-0.500", of split half sphere gauges for $25, if you think you might ever want to tackle something smaller than .30 Caliber. These tools turn out to be pretty useful for things like checking cylinder chamber throats in revolvers and bore diameters in barrels with even numbers of lands. Slugging is more precise, but you also need to be using a micrometer with 0.0001" resolution to see the advantage of the slug. To be frank, you get more reliable readings from a micrometer for what you are doing, too.

You also probably want to size the hole to give you your minimum ID with a freshly annealed case, as the softer necks will spring back less, being less work-hardened. That way a hardened one may not spring back too much. I would start there, then widen it more if you find your most used and unannealed cases are coming out smaller than they need to be. Ideally, of course, you'd want a number of dies, like Bart has, each maybe a thousandth apart so you can always find one that produces a good ID, regardless of neck wall thickness and loading history. Also, if you intend to do any neck turning, do that first.

Regarding the press threads, as you might imagine, an imperfectly perpendicular thread axis inside a lock ring can cause the die to be slightly cocked when the ring is tightened. Feamster's method was simply to slip an O-ring over the die thread to sit between the locking ring and the press, then didn't tighten down too hard. A Lee lock ring not tightened 100% will do the same thing, but with less adjustment range. This arrangement tends to let the triangular profiles of the press and die threads self-align coaxially. It also allows for slight tilting alignment. It's just giving self-alignment an additional degree of freedom, same as a floating reamer holder does for rifle chambering.

When I first tried this, I didn't get a clear improvement. But I was reminded of something a tool maker I used to work with liked to say: "Only God is perfect. Everything else has tolerances." The press threads seemed pretty smooth and clean and well-fitting, but I lapped them to a polish using a Redding die's threads as the male lap, and then lubed them with lithium grease to help them slip. That seemed to give me a little less runout on finished rounds. I don't have a statistic for you, but my memory says it was around 0.001"-0.002" improvement on .30-06 case (Feamster was working with .308 Winchester). I switched to using a Forster Co-ax press for precision rifle loading years ago, and it doesn't have a die thread so I haven't used the method for some time.

When cases you have start out fired by an unknown gun, they can be large enough that you'd find running them through a standard sizing die before running them through a small base die will save you some effort. It's not worth buying the second die if the SB is the only one you have, and since you've solved the lube problem with it, but I think it explains the extreme effort you encountered.

STP is cheap at Wally World. Just the standard treatment in the blue bottle. Less than $1.50 last time I got any. I'll note that a few folks have also mentioned switching to lithium grease as a case lube. You can usually get it in a plastic squeeze tube or in a plastic tub at Lowe's or at an auto supply store. Lowe's sells a squeeze tube of Ultra Lube white lithium grease. I haven't tried that brand yet in a sizing die (I hate sizing die experiments, having stuck cases before), but I can tell you it's extremely slick in other applications I've played with it in. It's a vegetable-based product and claims to be four times more slippery than its petroleum-based competition. I just haven't decided which die to test this claim in yet.