Neck pain

[Unclenick]

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The X-die feature that stops neck lengthening by limiting how far forward the case mouth can be extruded by the die is machined into the die body. So if your case length limit is 2.540" and you use a standard shell holder, the die has to be cut, so the case mouth stopping feature is no more than 2.540" above the case supporting ledge in the shell holder. Otherwise, your case could grow to exceed SAAMI's maximum case length. If you unscrewed the die body, say, 0.005", then you would move that case mouth stopping feature up 0.005" along with it, so now it won't stop the case from growing until it is 2.545" long instead of 2.540" long.

All the above assumes ideal dimensions, however. Your die's actual stop is likely to be located to allow case length to grow a little shorter than 2.540" with a standard shell holder. RCBS told me they hold die tolerances to ±0.002", so I would not be surprised if it turned out your stop was set to limit the case to 2.538" or even slightly shorter. That means you could turn the die out by the difference between that actual number and 2.540" and still have your cases conform to SAAMI drawings. Of course, you would need to measure the length of a case that you had first trimmed per RCBS X-die instructions and then fired and reloaded a half dozen times to be sure the X-die was controlling its length and see what that number is in your particular copy of the die.

Then comes the question, how close to the SAAMI drawing do you actually need to be? The point of my previous post was that even though the SAAMI maximum case length for 270 Win is 2.540", your gun may let you get away with 2.550", which would mean you could turn the X-die up as much as 0.010" out of contact with the shell holder (or in contact with a Redding +10 thousandths Competition Shell Holder) without getting into pressure issues because a case that long should still fit in the chamber OK.

I think the above should be safe also because some of the old-timers (Townsend Whelen, for one, IIRC) said they never trimmed their cases; instead, they let their chambers do what the X-die does. I will not go so far as to recommend that because you want the case shoulder to be able to reach the chamber's shoulder to center the cartridge in the chamber. A neck that hit the start of the freebore (or ball chamber taper in the 270 Win) first would not let that happen. But if you have a typical chamber that is around 0.002" longer than the SAAMI minimum, letting the case get 0.002" longer than SAAMI maximum won't during resizing won't hurt anything, so turning the X-die out that far or using a +0.002" deck Redding Competition Shell Holder should not cause safety issues.

Take it all with a grain of safety salt in mind. I would still cast or slug the throat of the chamber to know what your gun actually has there.

[cdoc42]

Well, here's my limit of comprehension in this arena. I couldn't get Hornady 140 SST's in .270, so the dealer talked me into Nosler 140 Accubond at $40/50. Since I am driven to experiment, I bought them, came home and resized 10 cases that set the shoulder back 0.002." Every one was over 2.540" which forced me to trim to 2.530. Five of those were assigned to Nosler 140 Accubond at 0.015" from the rifling and the other 5 were assigned to Nosler 140gr Ballistic tip. The Accubonds looked longer, and, sure enough, the COL to Ogive was 2.970" while the Ballistic tips were 2.760, with both being 0.015" from the rifling. I don't understand how factory rounds deliver satisfactory results for average hunters.

[Bart B.]

As long as the chambered cartridge is reasonably straight, bullet's can have two tenths inch jump to the rifling and shoot well inside 1 MOA at 100 yards if all else is up to snuff. They stay straight going through the case neck into the throat.

Note that the bullet diameter that first contacts the throat is about .002 inch less than its maximum diameter.

[cdoc42]

I tested accuracy today with 5 rounds each of .270, shooting Hornady 140gr SST, with the same charge, primers, trimmed case lengths, and seating at 0.015" from the "leade."
One group was neck-sized (and I made sure they chambered), the other was "full-length" resized with the shoulder set back 0.002". There was absolutely no difference in the point of impact. I assume it was because the shoulder set-back was not truly "full-length" resize. Correct?

[Unclenick]

Belief that a small jump will guarantee accuracy is misplaced. Writing in the 1995 Precision Shooting Reloading Guide, the late Dan Hackett described seating bullets 0.20" off the lands in his 40X in 220 Swift, but never being able get 5-shot groups below an average of 0.5", with the spread being 0.375" to 0.75", which is typical of variation percentage among sample sizes of five. Then one day, in switching bullet's he accidentally turned the micrometer seating depth adjustment on his seating die the wrong way and seated the bullets too deeply, putting them 0.050" off the lands. He didn't notice until he had 20 rounds loaded. He considered pulling them, but decided to go ahead and shoot those rounds in practice, expecting the longer jump to spoil the groups. To his astonishment he got two 0.25" groups and two true bugholes in the low 1s.

[Bart B.]

Case shoulder is typically set back a bit in all full length sizing procedures.

[cdoc42]

Unclenick, that sure complicates the hobby, doesn't it? I wonder how far out benchrest shooters have gone. Generally I find 0.015 or 0.020 inches will give me 3 or 5 shot satisfactory groups that repeatedly fall under 1 inch. I have a built-in red flag that prevents me from trying to get close to 0.01".

Only once have I wandered astray. I replaced the drop-down magazine in my Remington Model 700 with a removeable magazine, but I had to seat the bullets no closer than 0.06" to use it. The 5-shot groups hover between 0.966" and 1.22" at 100 yards; I can consistently hit balloons at 200 yards and drop the bullets into a 6-inch circle at 300 yards, so, with confidence, I reserve this rifle for deer hunting.

At the other extreme, seating a 65gr Hornady V-Max at 0.015" in a 6mm PPC, and at 100 yards, I fired 2 rounds at each of 4 one-inch bulls. The 8 shots averaged 0.116" and target #2 measured 0.007".

I suppose on a day with nothing else to do, I should seat toward 0.05" or so to see what happens.

[Unclenick]

You can read Berger's information on the concept, here.

[cdoc42]

Thank you!

[cdoc42]

I read the Berger info and ran an accuracy trial this morning. My LGS can’t get Hornady 140gr SST for my .270, so he suggested I try Nosler 140gr AccuBond.

I only loaded 4 sets of 3 rounds since the cost was $83/100 as compared to the SST of about $40/100.

I had previously fired a 4-shot group seated at 0.015” and it measured 0.973”.
Here’s the results:

1) Seat 0.02” – group size 1.973”
2) Seat 0.05” – group size 1.223”
3) Seat 0.09” – group size 0.410”
4) Seat 0.130” -group size 1.473”

I was simply amazed. Now, of course, I’ll need to confirm that with another larger series seated at 0.09”.

[GeauxTide]

For 40 years, I've placed a penny between FL Sizer and shell holder because I accomplished the same thing as a neck sizer in the variety listed below. I only FL size cases for pistol and AR calibers.

[reynolds357]

Originally Posted by cdoc42

In a lifetime, you can never experience everything. As time goes on, even things you knew but forgot about, return to remind you.

For my .270 I compared full-length resizing, moving the shoulder back 0.002" to just neck-sizing, using a specific die, and I found I squeezed out tighter groups by neck sizing.

So I loaded up 50 rounds of 140gr Hornady SSTs and went off to chronograph them. After 5 rounds, I found one that would not chamber, but neither could I remove it without using a wooden block and hammer to knock the bolt open.
As I continued, I found more and more of the same but I had learned not to try to fully engage the bolt.

I came home and measured the necks. The Lyman manual shows the neck should be 0.310 inches. Those that chambered were that, or slightly below. Those that would not chamber were above 0.310 inches.

I pulled the bullet, poured the charge into a full-length sized and primed case, removed the depriming pin from the die and full-length resized the case. The length was fine, so I returned the powder charge and seated the bullet. It easily chambered.

In 1976 I read "The Complete Book of Practical Reloading" by John Wooters, so I rechecked what he said about neck sizing. Sure enough. When you neck size, expect to full-length resize after about 3 or so rounds. He didn't find much advantage to it, so it was his policy to always full-length resize.

So now I have a pain in MY neck, faced with pulling about 30 rounds and going through the process described above. I think I'll retire the neck-sizing die.

It really depends on exactly how you neck size. Neck sizing has fallen out of fashion in the bench rest world. I see no reason to neck size only unless you are loading for a rifle or pistol that has headspace issues. Neck sizing still seems to be more accurate in a TC Contender and Encore. Past that, I don't do it.