Neck Turning

I understand why people trim neck wall thickness: uniformity of bullet pull, some custom rifle require a certain outside diameter of the neck, etc. I just ordered 500 Lapua cases (.308) and my questions are:

1.) Lapua neck thickness is usually around 0.015" to 0.016", what should I trim them to...0.015"?
2.) I have a handheld Hornady neck turner. I have heard of people placing the rim of the case in a drill (making it into a handheld lathe) to speed up the process. On the surface it sounds like a good idea as long as you don't damage the rim, but what are the pros and cons of doing this? Should I use a drill?
3.) In your opinion and/or experience has neck turning improved accuracy?

Thanks!

We use Sinclair neck turners and chuck the brass on handheld screwdrivers. I believe a drill may turn the brass too fast.

We found a HUGE drop in velocity extreme spread and velocity with neck turned brass. I believe this definitely improves accuracy at longer ranges. At 100, I don't know if it would make a difference.

Hi Geaux68,

at first the Lapua brass is a good choice! I´m shooting long range competitions since years with my .308 and used at first the Norma cases but found that the Lapua brass is much better and you can use them longer. What i did, and i´m sure that you did it too, is to necksize any of the brass before the first use. They had some dents and i wanted to have the same pressure at all. After fire forming i shortened the brass and deburred the inside of the primer holes and the outside. A good friend makes specialcustom made dies and he made me a necksizer die that equaled the thickness during the sizing process which is safer and it brought a highly accurate sized brass. To make it short , only the trimming of the thickness brought nothing but the complete procedure brought some millimeters at 100 meters. And to make it perfect, i´m using the Lapua Silver Scenar bullets in 167grs. and 185 grs. because they have only 2/10 of a grain diffrence between in maximum. Best is try out with some brass by making every single step with some of them and shoot them so you can see if there is any extra accuracy.

Gebirgsjaeger wrote:Hi Geaux68,

at first the Lapua brass is a good choice! I´m shooting long range competitions since years with my .308 and used at first the Norma cases but found that the Lapua brass is much better and you can use them longer. What i did, and i´m sure that you did it too, is to necksize any of the brass before the first use. They had some dents and i wanted to have the same pressure at all. After fire forming i shortened the brass and deburred the inside of the primer holes and the outside. A good friend makes specialcustom made dies and he made me a necksizer die that equaled the thickness during the sizing process which is safer and it brought a highly accurate sized brass. To make it short , only the trimming of the thickness brought nothing but the complete procedure brought some millimeters at 100 meters. And to make it perfect, i´m using the Lapua Silver Scenar bullets in 167grs. and 185 grs. because they have only 2/10 of a grain diffrence between in maximum. Best is try out with some brass by making every single step with some of them and shoot them so you can see if there is any extra accuracy.

My steps for preparing new brass are:
1. Full Length Size
2. Trim Case Overall Length
3. Uniform Primer Pocket
4. De-bur/Chamfer Flash Hole
5. Chamfer Case Mouth
6. De-bur Outside of Case Mouth
7. Check Neck Wall Thickness (I reject the case if I see a variance great than 0.0015")
8. Turn Necks (I haven't started doing this yet)
9. Tumble and Inspect Flash Hole
10. Sort by Case Weight

I'm currently shooting 42 grs. of Varget with a Sierra 175 HPBT and BR-2 primers. While my groups are getting tighter, I want them to be better. My extreme spread is still between 35 and 50 fps. Things I have yet to try: separating bullets based on ogive & weight, weighing primers, turning necks, etc.

jbpmidas wrote:We use Sinclair neck turners and chuck the brass on handheld screwdrivers. I believe a drill may turn the brass too fast.

We found a HUGE drop in velocity extreme spread and velocity with neck turned brass. I believe this definitely improves accuracy at longer ranges. At 100, I don't know if it would make a difference.

The handheld screwdriver sounds like a better way to go, but is there a chuck attachment for them? Is this something I can get at Lowe's, I've never looked for one? Thanks, great advice!

There is an attachment, but I'm not sure where SGMJody got it. Maybe he'll comment here.

Than you´ve done the most you can do! If you want to go extreme, you can measure the brass by weight and the bullets andmeasure the bullets diameter. The next thing you can do if you haven´t done it already is to mount a muzzlebreak to take away the gases from behind your bullet. This brings a lot ( for me noticeable 3mm in group diameter) but it may be that you have to change your load a bit, can be but must not be. It is only if the muzzlebreak has influence on the vibration behaviour of your barrel.

The screwdriver needs to be one that does not exceed 150 to 170 rpm's. The straight Black/Decker el-cheepo's do nicely. I have three because on .308 cases, you can only get about 15 necks turned before you have to recharge the battery. As for the holder for the brass, Sinclair makes a case holder set that comes with the driver and cartridge specific case holder.

http://www.sinclairintl.com/.aspx/pid=45124/Product/Sinclair-Driver-Caseholder-Set