Home Forums Reloading Big Game Rifles Concentricity issue with brass?

Give that diagnostic routine I outlined a try. It may well help point the finger at the right thing.

Inconsistent neck thickness is minimal with a Lee collet die on my brass. under a .001

A mild charge might take longer to form than you think !!

Lee collet dies do not affect the uniformity of the neck thickness.

He's loading for a 257 Weatherby. Published maximum charges were developed for factory style chambers/throats that have a bit of freebore. A max charge with the bullet in the lands is a fine way to achieve excessive pressure.

A agree a mild charge isn't what he wants for fireforming.

Simultaneously turn and ream the necks. That process generates a consistent thickness.

And it's not 257 Weatherby brass to start with.



Some folks are better off taking advice and not offering it.

Didn't see what the original die was to reduce the necks. If it was a neck sizer that is where your runout came from.

Yes they do......there is considerable less TIR when I indicate them. But hey you don't have to take my word for it ! I indicate them between the slot the collet leaves on the neck. Even though I polished the inside of the collet the best I could, slight impressions are left on the neck. As long as you stay away from them while indicating, you're fine.

ooops sorry about that.... LOL apologies. Get a grip man, you ain't perfect either !!

Indicated runout on the outside of the neck and neck thickness are not the same thing.

Poppy cock. I used to use a tube mic, and TIR does the same thing. Whats the difference if you put a neck on an anvil measuring with a spindle verses on a pilot on a concentricity tool and indicate with a dial indicator ? ! nothing. And the spindle really isn't conformed to the curve on the neck like the anvil portion. Splitting hairs here friend.

The "lightest charge that you can" may disappoint you. It takes some pretty serious pressure to move the brass around. Wimpy loads will likely just confound the problem. After being sure you have the proper neck clearance, I would start about midway & work up until you find something that forms the brass well. Powders on the quicker side of the data will have a bit more snap than the real slow burners. Small batches until you see how it all works out before loading them all. I've been doing this for a few years now & recently had to shoot some pieces of reformed brass for a new rifle 3 damn times before they filled out enough to headspace properly. It's always an adventure & the PPU brass is rather stout. When I do the other 30 from this batch, I'm sure they'll be fine after the 1st firing.

Are the cases with the runout in your OP already fireformed?

After they're formed, you can fool with runout if you need to. It's a fool's errand trying to fix something that cant be easily fixed with unfired brass that's been abused numerous times, from the packaging machinery, to the monkeys at the USPS warehouse, to the guy with the loading press. Body dents can play hell with bullet concentricity. With a factory rifle & hunting loads the average shooter probably wont see the difference in bullet runout up to near .010". Going back 30 or 40 years, factory brass often had up to .006-.008" neck thickness differences in some lots. We still managed to shoot small groups & kill groundhogs at distance. Runout gauges are kinda like the borescopes of reloading tools... fun to play with & can be used to solve real problems, but create much ado about nothing scenarios more often than not.

If you need a few pieces of 257 Wthrby brass for comparison, I have about 1/2 of an old box unfired that I found rooting around downstairs last year.

Good luck & have fun.

RCBS Full length sizing die is what I used.

Generous offer on brass. How much for them?

Thanks

HeavyBarrel

You're thinking about neck wall sorting, like so:




He's talking about neck runout measurement, like so:

Yes

HeavyBarrel

What are you talking about? When sizing a case the collet never makes contact with the mandrel. On top of that, how does the recess in the cap affect the operation of the collet anyway? The recess is there simply to provide clearance for the "nail head" of the mandrel.

In my work, I had to see where the problem was. That involved using dial indicators, mics and even feeler guages. That jig measure neck thickness not concentricity . Easier and quicker than using a tubing mic, but not nearly as fine. My tubing mic measures a 1/10 of a thou. That jig is also more expensive than my KBC house brand Chinese mic. Your reference point should be the case itself .

And others are talking about neck wall thickness too math major

Anybody have a giffy of a wheel stuck spinning in the mud?

Or a sinking ship?

How about a dumpster fire.