10 FCP SR handloading question

[trentcwwilson]

I finally broke down and bought a set of Redding Deluxe dies (84155) and I know neck sizing gets the most accuracy, but I can't seem to get it right. I've got 3 cases: one that was shot, one that has been deprimed and neck sized per the Redding "directions", and one live that was FL sized and loaded for the 185 gr Berger Juggernauts. Now, I know how stiff the bolt is after firing the 185 Jugg loads. Case 1 (fired) feels stiff as usual when cycling the bolt. Case 2 (neck sized) is slightly less stiff, and Case 3 (live) cycles freely as a FL sized round should. My question pertains to Case 2. I've put Dykem on all the necks and shoulders and cycled them and I'm getting contact anywhere from 30-35 thousandths down from the shoulder on the case body. Is a neck sized case supposed to fit this tightly to the chamber? I'm afraid if I load the neck sized case, I'll run into pressure issues. I'm running 44.6 grains of Varget, which is max, per Berger, for their 185 grain Jugg. Anyone have enough loading expertise to chime in?

[trentcwwilson]

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[Burr]

I'm not following you where a neck sized case will create a higher pressure reloaded round?

Here's what I have found when it comes to neck sizing only, and pressure. If you have a set of case comparator gauges - I have found reloads that are at/very-near the max pressure/velocity range will move the shoulders forward about .002 more than milder loads. In practice - the measurement to the shoulder is the same on every test load - until the very last or fastest test load charge. If I get to that hottest level, being able to chamber that brass with neck sizing alone may be possible for the second load, or the third, but somewhat quickly the brass will be so tight it will not chamber without FL sizing.

I'm fairly certain diameter changes would behave similar to length to shoulder. The brass after stretching and then relieving after a shot stretch a little more, and relieve the same amount - leaving it a little tighter in the chamber.

I'm not saying neck sizing is better than other methods, but it's a method I'm wanting to use, and at the same time obtain reload-ammo that reliably chambers. To get reloaded ammo that reliably chambers I've been using a body die in combo with a later step to neck size. With the body die, I carefully measure and adjust to move the shoulders back - but in your case the case-body is also being resized in diameter.

Every chamber is a little different. If your reloads are not at/near max - it's also possible your chamber is min spec. I had a Tikka like that in 300 WSM. I would be tight chambering factory ammo. I ended up moving the shoulders back .002 from factory ammo, and the reloads chamber and bolt close with no resistance/as compared to factory ammo that is tight on every round.

[trentcwwilson]

These are near max/max loads. 44.7gr Varget for 175 SMKs/44.6gr Varget for 185 Juggernauts. My question basically boils down to this. I feel a bit of pressure chambering a neck sized and trimmed empty case. Less than what I get chambering a fired case. Is what I'm feeling pressure being put on the shoulder, and is it going to cause a pressure spike with my loads? I know eventually I'll have to either bump the neck or FL size the cases, but I've got plenty of cases that have one fire forming on them.

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[bigedp51]

If the case has unequal case wall thickness the thin side of the case expands more and the case will become warped and egg shaped.

Below advertisement for the NECO case gauge http://www.neconos.com/NEWDIAL2.JPG

NECO CONCENTRICITY, WALL THICKNESS AND RUNOUT GAUGE
This Case Gauge is designed to measure:
1) The curved "banana" shape of the cartridge case;
2) The relative wall thickness variation of a cartridge case;
3) The cartridge case head out-of-squareness;
4) Individual Bullets - out-of-round "egg shape" and/or
curved "banana" shape (excepting very small bullets);
5) The seated bullet and cartridge runout of loaded rounds. The accuracy of any firearm is determined -- and limited -- by the quality of the ammunition shot in it. The effect of imperfections in ammunition is cumulative; each flaw adds to the influence of all others. Precision shooters spend much time and effort "uniforming" cartridge cases, using advanced techniques to eliminate variation. Yet until recently, one of the most important of these variations has not been susceptible to detection by any device readily available to marksmen.

http://www.neconos.com/NEWDIAL2.JPG

Bottom line, a full length resized case with minimum shoulder bump gives the case a little wiggle room to allow the bullet to be self aligning with the bore. Meaning a warped egg shaped neck sized case will allow the case body to cause bullet misalignment with the axis of the bore because the case body contacts the chamber walls. (in a pinball game its called "tilt" and game over)


http://i.imgur.com/Y3IiYL5.jpg

[trentcwwilson]

If the case has unequal case wall thickness the thin side of the case expands more and the case will become warped and egg shaped.

Below advertisement for the NECO case gauge http://www.neconos.com/NEWDIAL2.JPG

NECO CONCENTRICITY, WALL THICKNESS AND RUNOUT GAUGE
This Case Gauge is designed to measure:
1) The curved "banana" shape of the cartridge case;
2) The relative wall thickness variation of a cartridge case;
3) The cartridge case head out-of-squareness;
4) Individual Bullets - out-of-round "egg shape" and/or
curved "banana" shape (excepting very small bullets);
5) The seated bullet and cartridge runout of loaded rounds. The accuracy of any firearm is determined -- and limited -- by the quality of the ammunition shot in it. The effect of imperfections in ammunition is cumulative; each flaw adds to the influence of all others. Precision shooters spend much time and effort "uniforming" cartridge cases, using advanced techniques to eliminate variation. Yet until recently, one of the most important of these variations has not been susceptible to detection by any device readily available to marksmen.

http://www.neconos.com/NEWDIAL2.JPG

Bottom line, a full length resized case with minimum shoulder bump gives the case a little wiggle room to allow the bullet to be self aligning with the bore. Meaning a warped egg shaped neck sized case will allow the case body to cause bullet misalignment with the axis of the bore because the case body contacts the chamber walls. (in a pinball game its called "tilt" and game over)


http://i.imgur.com/Y3IiYL5.jpg
With my Shilen barrel and custom reamed chamber, I've yet to run into cases so far out of concentricity that it's an issue.

[tcoz]

I have the same rifle as you do and I don't neck size. I've yet to see any evidence that neck sizing increases accuracy especially if you're only bumping the shoulder .001-.002. The advantages to neck sizing are that you don't have to lube cases and also increased case life but only bumping the shoulder a thou or two won't have much, if any, adverse effect on case life and lubricating cases isn't a big deal to me. Even if you neck size you're still going to be required to f/l size every few firings. I'd rather have a perfectly resized case every time.
This is just the way I do it. Many (maybe even most) people neck size.

[trentcwwilson]

Well, I bumped the shoulder on a load and I'm gonna see how they compare. 44.6gr Varget and 185 Berger Juggernauts seem to be the ticket.

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[bearcatrp]

You can take a fire formed case and send to one of the companies that makes dies to have one made for your rifle. Draw back is no one will be able to shoot that ammo who has the same caliber. I have always full size my cases then use a custom iron for neck expansion from K&M.

[trentcwwilson]

You can take a fire formed case and send to one of the companies that makes case gauges to have one made for your rifle. Draw back is no one will be able to shoot that ammo who has the same caliber. I have always full size my cases then use a custom iron for neck expansion from K&M.
As a handloader, no one will be using my personal brass anyways. My ammo consumers pay for new cases when I load for them. I don't trust range brass anymore. I've decided to try bumping the neck. Loaded a set of cases with my best loaf and I'll see if they tighten up. If not, I'll stick with FL sizing.