neck turning

[acts238]

someone please exsplain to me the purpose & process of neck turning
is neck turning just for reducing thickness of brass
after forming brass from a larger diamenter caliber ?
say forming 6.5 saum brass from 300saum?
or is there more to neck turning than that
thanks for any responces

 

[Break Bad]

From what I understand it is to achieve a more uniform neck tension, especially if you a forming to a different caliber. If deformities exist inside the neck I would imagine they would affect the internal ballistics...how long the neck holds onto the bullet and allows pressure to build? I have never turned but am interested in adding it to my rotation.

 

[18Echo]

I do it on my LC 308 brass to make the neck thickness consistent, therefore giving even tension around the whole bullet. Neck turned and annealed lake city is just as good as Lapua in my experience.

If you neck up, you move thicker shoulder material into the neck and sometimes neet to remove that extra meat. I neck up up .338 win mag to .375 though and didnt encounter that problem.

Some people also have a chamber cut to make it a "tight neck" chamber and you need to remove material just so your case will fit.

I don't recall off the top of my head why you might need to do it if you size down. I know you may have a donut inside the neck that you need to move to the outside and then trim off...

 

[former naval person]

When you neck down a case...say .308 to .243 the neck gets thicker. If the resultant thickness plus the seated bullet exceeds the chamber neck diameter, you'll have a bad pressure situation and wildly inaccurate results.

 

[bjay]

Does this sopose to add accuracy?

 

[oldfatguy]

Have experienced high dollar brass with as much as 0.002" variation in neck wall thickness on the same piece of brass. turning necks greatly reduces the wall thickness variation. Of course the rest of the case still has the thickness variation.

And anything done to reduce round to round variation can't hurt accuracy.

OFG

 

[BuzzBoss915]

Neck turning is something that should be done with knowledge and a goal. "Tight necked chamber" was mentioned above, which is a custom modification, and in that situation, the necks need to be turned in response. But, just neck turning, as a buzzword is ill-advised, it is an advanced technique, and can cause more harm than good if doing it just because it is recommended as an accuracy procedure. In some "cases" just a light turn of maybe 50% of the neck area might be an improvement but turning it down uniformly for use in a factory chamber might not be a good idea. I don't know if I am making any sense, but the main thing is, neck turning requires caution, and a clear idea of what you intend to accomplish. BB

 

[M40_A1]

If you use a bushing die with no expander, you should turn the necks.

 

[VKC]

Neck turning provides more consistent thickness and thus consitent bullet seating and concentricity. It provides more predictable bullet tension. Also removes donut with resizing. Thick necks with tight chambers can be a problem and spike pressures.

Some calibers and rifle chambers need it others don't.

 

[old_heli_logger]

Properly done, neck turning will make your neck thickness the same all the way around. This will help center and align your bullet with your bore and will improve your accuracy. Don't take off too much or your brass will be worked more and will shorten its life. I usually clean my necks up between sixty and eighty percent.
Good luck!