I am relatively new to neck turning. I have the K&M turner with expander die. I am turning some 6.5/284 shells and no matter how much I turn off the neck (.0005-.004) The concentricity remains the same. If the neck is out of round .004, then it remains out that much even after turning. I have tried running the brass through my bushing die afterwards but nothing changes. I have tried by hand and with a drill. What am I doing wrong???? I just want to get brass around .002-.001 runout at the neck!!
Neck turning problems!!!
- Thread starter itfliesitdies
- Start date
Turn them so your loaded round diameter is .002 under your chamber neck diameter.
Don't bother to check for concentricity yet.
Load them with a full power load fire them, (get zero's, practice, shoot groups etc) then neck size them with a good bushing die and load them again. Now check your loaded rounds for concentricity. I will bet you'll find the numbers greatly improved.
Danny
Don't bother to check for concentricity yet.
Load them with a full power load fire them, (get zero's, practice, shoot groups etc) then neck size them with a good bushing die and load them again. Now check your loaded rounds for concentricity. I will bet you'll find the numbers greatly improved.
Danny
Yep, it's pretty much a wasted effort to neck-turn new brass unless you have a really tight-necked chamber profile & must do so to get loaded rounds to chamber & shoot safely. Do you know FOR SURE what the neck diameter of your chamber was cut to?
Neck turning isn't a cure for eccentric necks....
Neck turning isn't a cure for eccentric necks....
If your expanding them its fine to turn them when they are virgin which i would suggest you do everytime your neck turn. If you do wait i would anneal them before you turn they can get hard to work with after you fire them and try to turn before you anneal. Once or twice fired should be ok to turn. But all brass varies greatly in hardness so its tough to tell unless you try it. You just want to make sure its not getting brittle at all before you do a bunch of cases.
bozo699
Gold $$ Contributor
Jerry,
No I Don't have a no turn neck. I just always noticed the same problem that ifitfliesitdies was having. I noticed after firing it would become concenric again so was never to worried about it,also figured the case must be out of round. Now I know for sure. Thanks
Wayne
No I Don't have a no turn neck. I just always noticed the same problem that ifitfliesitdies was having. I noticed after firing it would become concenric again so was never to worried about it,also figured the case must be out of round. Now I know for sure. Thanks
Wayne
Recently I've found that I get more consistent neck tension if I anneal even brand new cases. I trust the tell-tale appearance of Lapua cases though. Those I leave alone for first use.
Careful annealing will help with every respect of making your cases fit your chamber best, whether upon firing (when the case must conform to the chamber, then spring back more uniformly) or upon resizing when the metal's only going one way (or so you hope!).
Uneven brass temper causes case necks to spring back in a non-uniform manner. I anneal cases once they come out of the tumbler from the first cleaning, then they get sized and perhaps neck turned, then cleaned of lube with another, shorter run thru new corn media before priming.
Light turning of new cases (to make the neck walls more uniform) may help reduce eccentricity once cases are fired and resized if only because making the thickness more uniform allows them to better form themselves to your chamber. Slight differences in neck thickness can cause the inside diameter to be pushed off center, increasing future bullet runout even while case neck runout is improved!
Cases invariably have non-uniform wall thickness. Brands that have higher prices generally, but not always, have less of an instance of this condition, i.e. their production methods & quality control ensures a greater degree of wall uniformity.
Differences in case wall thickness will lead to eccentric cases sooner or later because of the different rates at which thinner vs. thicker brass are affected by repeated firings / resizings. The less you start with the lower your chance of encountering issues down the road.
Careful annealing will help with every respect of making your cases fit your chamber best, whether upon firing (when the case must conform to the chamber, then spring back more uniformly) or upon resizing when the metal's only going one way (or so you hope!).
Uneven brass temper causes case necks to spring back in a non-uniform manner. I anneal cases once they come out of the tumbler from the first cleaning, then they get sized and perhaps neck turned, then cleaned of lube with another, shorter run thru new corn media before priming.
Light turning of new cases (to make the neck walls more uniform) may help reduce eccentricity once cases are fired and resized if only because making the thickness more uniform allows them to better form themselves to your chamber. Slight differences in neck thickness can cause the inside diameter to be pushed off center, increasing future bullet runout even while case neck runout is improved!
Cases invariably have non-uniform wall thickness. Brands that have higher prices generally, but not always, have less of an instance of this condition, i.e. their production methods & quality control ensures a greater degree of wall uniformity.
Differences in case wall thickness will lead to eccentric cases sooner or later because of the different rates at which thinner vs. thicker brass are affected by repeated firings / resizings. The less you start with the lower your chance of encountering issues down the road.
dreever said:
I tried the .002 rule but it didn't work. The inside diameter was still .006-.008 tighter than bullet. 308 brass necked down to .290 for a 260 remington. The chamber is .297 so I trimmed the brass to .015 thickness. Unfortunately this made it too difficult to seat teh bullets. Once I trimmed them down to .013 and used a 289 bushing I'm now ready to roll. I hope.
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