Neck turning your Brass

[Lonewolf74]

Accurately a cast will be right but you can get a good measurement on fired brass,,the neck will spring back a little after firing but the chambers neck should be real close to .001 over the fired brass maybe .0015

So measuring the fired necks and add .001 should put me pretty accurately where my neck clearance is?

Will neck spring back be about .001 in circumference or diameter? Meaning do I add .001 or .002 (if circumference spring back is .001) to the measured diameter of the neck?

Finally what sort of clearance would be on the edge of being excessive?

 

[TwoMore]

diameter. lets say one of my chambers is a .316 diameter my fired cases are real close to .315, I have factory chambers that are fairly loose , like .321 neck on a .314 loaded cartridge so that is .007. I anneal those pretty often, my customs I usually try for about .003 to .004.

 

[TwoMore]

.003 to.004 would be on the tighter side .006 to .008 average saami, >.008 getting on the looser side

 

[Lonewolf74]

Thankyou TwoMore

 

[bigbulls]

I neck turn everything. Even high end brass shows its inconsistency when neck turning. You will see one piece that the entire neck is clean after turning and next piece will only be cleaned up about 90%. The main benefit that I have found is when combined with bushing dies you can control one of the most important key elements, neck tension. I run bushing dies with no expander installed. Running a bushing that will give me about .003 neck tension, then last step is I run a Sinclair NT mandrel which is .002 under bullet diameter through all my necks. I also anneal every firing. If you are looking to get low single digit SD's or keep ES to single digits consistently this will do nothing but help. Everyone has their own opinion of coarse. I have about 4 K&M neck turners along with drill adaptor. Once done I leave brass in adaptor on drill and polish neck up with steel wool inside and out. Best of luck.

This is exactly what I do. I thought I was the only one spending this much time on brass

 

[elf]

I buy a new NT for each new barrel I put on competition barrels. Most are K&M, but I bought a PMA NT tool last year and like it a lot. I keep the tool set there for the life of the barrel. I do not NT for hunting rifles. Neck turning puts a consistent diameter on the neck creating improved accuracy downrange. Clearance on a turned neck should not be less than .001" nor more than .006".

 

[243winxb]

Test using Savage Axis in 223, using standard RCBS fl die set.

Neck turned using a Lyman attachment for my trimmer. Compared 2 groups of each.

I noticed turned brass necks lasts longer, no neck cracks or splits.

In 243 win, bushing fl die has also increased brass life.

 

[gohring3006]

If you are going to turn necks, then you should be annealing, weight sorting, taking burrs out of the flash holes and measuring and correcting run out, other wise, all those potential problems cancels it out quickly.

 

[Mikecr]

I do not NT for hunting rifles. Neck turning puts a consistent diameter on the neck creating improved accuracy downrange.

Seems conflicting. What would you consider accuracy more important for than hunting?

Perfect annealing **** sure does function to reduce tension variance. But much of this is because it reduces tension overall. Less tension = less variance of it.
If your cartridge/load works best with higher tension than freshly annealed provides, then annealing will not be a gain for you. If you can't process anneal every case properly & the same, the again, annealing will not be a gain
IMO, best seating depth will provide biggest gain, regardless of tension.

I manage low tension for low variance of it, and anneal only when I actually have to reset my brass.. With minimal sizing from rational clearances, my re-annealing is more reload cycles down the road than most can make their brass last.

 

[tim_w]

I like all my case necks to be consistent even if its a factory chamber with lots of clewrance still want the neck to release the bullet evenly and that is irrespective of the clearance. Thus I skim all necks for stock guns.

For customs I like cases necks to be min 0.010 max 0.015

Chamber clearance 0.002-0.004 depending on use cartisge and caliber.

I have a theory on why it seems some find increased clearance for neck work better where it seems some BR set records with as little as 0.001. Neck runout from the shoulder junction. With the case seated against the shoulder the more runout of the neck the closer it is to one side or a point of the cbamber neck wall. If you are using unturned necks even more so as now there are thicker and thinner areas. Running neck clearance 0.001 is only 0.0005 clearance. we have seen various sizing practices effecti various areas of the case in terms of alignment with its centerline. Expander balls always leads to some neck to shoulder runout. Neck sizing without full case support. Neck bushing dies miss the bottom of the neck. In a tight clearance can be enough to binding and changing the release force of the forward part of the neck that is holding the bullet.

Anyways just a theory. In the BR game where .001* dif is group skze can actually matter making everything perfect with tight neck clearance maybe that little be extra but everything better be perfect. Most of us do not shoot nor measure our groups to tbat level of accuracy let alone tell the difference.

 

[J E Custom]

The main reason I turn the necks ,is concentricity. I like to turn the necks before it has been fired the first time. I prefer the Sinclair neck turner because it pre sizes the ID of the neck with a sizing mandrel first to fit the turning mandrel perfectly assuring that the neck wall is a very consistent thickness. Then when fired in a concentric chamber, (Custom) the case remains concentric when sized properly. (If the neck wall thickness varies, firing it in a concentric chamber will offset the ID of the neck by the thickness difference).

I try to find the best brass possible and even though it may measure only a half thousandths difference, I still turn it so all cases will have the same wall thickness. This gives me the best chance of loading concentric ammo. And true concentric ammo always shoots more accurately that ammo that is not concentric.

Of course, in poor chambers with low quality brass it may not make enough difference to be worth the effort, but it can't hurt. so start true and finish true. Even though the necks may thin over time and firings,
it will remain consistent and concentric through it's life.

J E CUSTOM

 

[Mikecr]

Tim_W's theory about better results with clearance is correct. It's chambered tensions.
But, this same path also contributes to the offending runout and chambered tensions to begin with. That is, people turn & size for more clearances, and this greatly contributes to the runout they're using clearance to resolve. Roundy roundy..

The guy that turns for actual benefit has a plan to reduce clearances, and sizing, so that runout is extremely low, and with this there are no chambered tensions. He can make a gun shoot with ~1thou of clearance, and very little variance in tension -with no need to anneal. No problem.

As far as neck thickness variance that you have, run a Sinclair/PMA mandrel through just prior to seating bullets. This pushes some of the variance outward -away from seating bullet bearing. Definitely reduces TIR.
And never, ever, FL size necks. There is nothing but detriment in this action, for both runout and especially tension. Just,, don't ever do this.

 

[mike06]

I neck turn everything. Even high end brass shows its inconsistency when neck turning. You will see one piece that the entire neck is clean after turning and next piece will only be cleaned up about 90%. The main benefit that I have found is when combined with bushing dies you can control one of the most important key elements, neck tension. I run bushing dies with no expander installed. Running a bushing that will give me about .003 neck tension, then last step is I run a Sinclair NT mandrel which is .002 under bullet diameter through all my necks. I also anneal every firing. If you are looking to get low single digit SD's or keep ES to single digits consistently this will do nothing but help. Everyone has their own opinion of coarse. I have about 4 K&M neck turners along with drill adaptor. Once done I leave brass in adaptor on drill and polish neck up with steel wool inside and out. Best of luck.

Remmy do you use a carbide mandrel that cuts the inside of the neck also? And also do you neck size again with your bushing die after turning? Thanks

 

[Remmy700]

Yes sir I do