Neck turning questions.

[crbrumbelow]

A few of my questions have been answered on other posts but I have got a few more. I recently got 100 pieces of lapua 308 win brass and a new Sinclair neck turner with the expander mandrel and die too. I read an article on this web site about neck turning that says to turn the necks again after you fire form them. I really am not turning to a specific diameter, I am just cleaning up the high spots. Anyway, I don't really like what I am seeing on this second neck turning. It seems that the cutter bites into the neck/shoulder junction a little more. My question is this. If I am just cleaning up 80% or so of the neck and not turning to a specific diameter, am I just wasting my time with this second neck turning? If so I feel like I may be on the verge of ruining 25 pieces of brass.

 

[chris308]

Depends, is it for a factory rifle? You`'ll cut into the shoulder more on a fired case as the shoulder is blown out more. If you do turn fired cases, be sure to size the neck down and re expand them. The out side of a fired neck will be perfectly round and any high spots will be on the inside. If it is a factory gun, I wouldn't even mess with turning them at all at least with Lapua anyway...chris

 

[crbrumbelow]

Thanks Chris. The rifle is built on a Rem. 700 action, shilen select match 5 contour barrel 24" finish length, Bell and Carlson medalist stock glass bedded and a badger ord. 3/8" recoil lug. The chamber is cut to "tight SAAMI" specs. I think I am going to start over with fresh brass and not turn them but once. This will ease my mind. I use the Redding neck bushing die and I wanted to turn the necks to take full advantage of the bushing setup and not pull an expander back through the neck.

 

[chris308]

get yourself a tube micrometer and learn how to use it,it does take practice) anyway this will tell you if you need to clean up the cases. My past experience with lapua 308 showed hardly any variation just like the 6br brass.I'm willing to bet you won't have to turn any cases. fwiw, i got a tube mic from midway for around $40.00,lyman... it's no starret but it will help alot.....

 

[mikecr]

What would be gained in turning AFTER fireforming?

 

[crbrumbelow]

Click Here
This is the link to the article. I was following the article to possibly sqeeze the last bit of accuracy out of the rifle. I just didnt like what I saw at the second turning of the necks. Has anyone used the Redding neck bushing die without the expander and with unturned brass? What kind of results did you get?

 

[tripcrow]

There are times when I’ll do a second neck turning session after fire forming. Especially when the necks after the first turning came out with too different thicknesses. If you’re going to do a skim cut and turn all the way down again, the neck has to be the same diameter all the way down to the shoulder junction. The only way I know to do that is to full length resize the cases without the die’s expander button being sure to bump the shoulder a little. If you’re just sizing with a bushing before turning you’re probably not getting the full neck. There’ll be a section that doesn’t get bushed on the lower neck that has been blown out past the diameter of the neck turner’s expander. So when you turn down past the bushed part of the neck you’ll be thinning that unsized section more than the rest of the neck. You may also want to get the 40 degree Sinclair cutting tool for your turner to keep from cutting into the shoulder so much.

 

[Elkbane]

1+ on getting a tubing micrometer, and pick up a micrometer stand as well - it serves as a third hand to hold the mike while you manipulate the case and the measurement racthet.

Unless you can mesure results, you don't know what impact on variability your operation is having. Hoping it helps is not a very good strategy for eliminating variability.
Elkbane

 

[MSwickard]

I read an article on this web site about neck turning that says to turn the necks again after you fire form them.

I would not turn the cases a second time. There really isn't a need. Just take the the neck turner and work down the case neck slowly them work it back up. This is all you need to do. Afterward, take some 600 grit sandpaper and run it over the neck. Done!

I really am not turning to a specific diameter, I am just cleaning up the high spots. Anyway, I don't really like what I am seeing on this second neck turning. It seems that the cutter bites into the neck/shoulder junction a little more. My question is this. If I am just cleaning up 80% or so of the neck and not turning to a specific diameter, am I just wasting my time with this second neck turning?

Yes