Case full-length resizing

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  • Last Post 24 April 2015
billglaze posted this 20 April 2015

I'm currently shooting, in sequence rotation, 50 Federal Match cases that the Marines kindly donated to the cause years ago.These cases have been neck annealed, and never full-length sized; they've been fired well over a thousand times.  (do the math<G>)  All firing has been with cast bullets.They slip into the chamber of the rifle with only the slightest of effort.  And, they are all index-marked.I have been working on the old-school drawing in my head from years back, that showed a cartridge before it's first firing, laying in the chamber tilted down at the base, with the bullet entering the barrel rather slonchwise; a definite no-no for a neophyte handloader, and, supposedly, an accuracy killer.  That picture has stayed with me lo these many years.  Recently, I've heard of several accomplished bench-rest competitors who full-length size on a regular basis.  Apparently, they consider it a necessity to maintain their considerable accuracy levels.I'm looking for all opinions, scientific, theoretical, anecdotal--just chime in.  I am not going to argue with any views; at the most, maybe a technique question or two.TIA Bill

In theory, there's no difference between theory and practice. In practice, there is. My fate is not entirely in Gods hands, if I have a weapon in mine.

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RicinYakima posted this 21 April 2015

Well, empirical, as in what I have tried. When I really started accuracy and precision shooting in the early 1990's with rifles, I full length resized for High-Power NRA matches. When I went to 1000 yard matches I looked at neck sizing but found problems. Mainly that no neck die would make cases that aligned with the bore. I had high hopes for the Lee crimp neck die, but it was the worse (Redding second!). The only thing that made worse ammo was to use the “Factory Crimp Die", guaranteed to make bad ammo for long range shooting.  Eventually I found out that the problem was the interface between press/shell holder/case head, but never looked back at neck sizing only dies. Now that I shoot about 10,000 cast bullets for every 100 jacketed, I don't need to do that work again at my age.  For cast bullets I have used a full length resizing die screwed down onto an 0.040” feeler gauge with the ram in maximum up position. I leave the case lube on the case when I fire them. I have since bought a CZ American in 223 Remington that will shoot 0.5” groups at 100 yards, but only with jacketed bullets and full length resized brass. So that is what I feed it, what it wants. FWIW, Ric

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OU812 posted this 21 April 2015

1996 RCBS David Tubb video stated full length sizing is good if your brass has equal or near equal wall runout. If not near equal the thin side of case wall will stretch and curve like a banana when fired causing bullet to tilt and wobble down range...especially in factory or “automatic” rifles with loose neck tolerances. Set the shoulder back no more than .002".  He also recommends turning case necks.   He mentions neck sizing ...works good in bolt action rifles...turn the necks for equal release.

  The RCBS Precision Mic is a verygood tool to use when measuring shoulder set back of high powered jacketed loads. Cases seam to shrink with lowered powered cast loads...the precision mic will tell you how much...usually .004-.005.

  The NECO tool is verygood for measuring case wall runout and concentricity.

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Wineman posted this 21 April 2015

It is apples and oranges, well pressure and high pressure. The cast loads are 20,000 psi and the full power loads are 55,000 psi plus. The brass behaves differently at twice the working pressure. The BR, XTC and LR cases get stickier and sticker as the neck sized brass is hammered to the chamber shape and does not rebound or come free like the cast loads. Some of these rifles have $1,000's invested and galling of the bolt lugs, hard bolt lift and sticking are just not tolerated. A good rifle and a shoulder set back of 0.001” in the die gives them 8-10 reloads, plenty of use for a piece of brass. They also put more time and effort into brass preparation, neck turning, wall thickness measurement and concentricity, you know all the stuff we want to do but may not have the platform for getting all the benefits.

Dave

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Ken Campbell Iowa posted this 21 April 2015

when thinking about hot loads making brass stick ... it is fun to consider that not only the brass expands upon firing .... but the rifle barrel chamber is expanding also . of course the brass expands as far as it can go .

with hot loads, the steel expands more, but ( within it's elastic limit ) returns to previous diameters . the brass in hot loads follows the steel, but doesn't quite come back to starting size. thus it seems stuck ... but it isn't exactly because it has been pressed harder against the chamber .

the fun part is when the load exceeds the elastic limit of the steel . ( a little bit more powder after your primers start falling out ... )

ken

fwiw, norma and nosler brass usually is so soft it just sticks at random and gives false pressure alarms .

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billglaze posted this 24 April 2015

Recently pulled out of storage a 220 Swift; has my Dad's old 20x STS scope.  Hasn't been fired for at least 35 years; too much else going on.  Decided, in spite of the problems joeb has been having with .22's, to dust off my old Lyman moulds and try some cast. (I mean really, really old moulds.)The only cases available now are W-W; years ago I much preferred Rem. cases; they were quite a bit harder, and lasted longer,  with less expansion.  Also, despite Phil Sharpe's stating that “220 Swift case necks tended to thicken with repeated firing” that, in fact, my cases had the necks progressively thinning until, in some cases, they would no longer hold a jacketed bullet.  Unfortunately Remington makes these Swift cases only on a “seasonal” basis, (whatever that means) and they are currently unavailable.  When available, I'll buy a quantity; until then , I'm strapped into W-W. However, I did find out recently, that the rifle with 4064 and a 55 gr. Sierra, will shoot 5 into <.5", which means it is a satisfactory platform for some experimentation.  Results?  TBA.  I'll keep the group advised, if there's any interest.

In theory, there's no difference between theory and practice. In practice, there is. My fate is not entirely in Gods hands, if I have a weapon in mine.

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