Posted by Stuart Elliott on
URL: http://oldforum.flyshooter.com.au/Outside-Neck-turning-Inside-Neck-Reamer-tp5706943p5706945.html

Peter,
Its outside neck turning because inside reaming will not improve the thickness uniformity of neck walls
My advise has always been... if you decide you need to do case neck turning then you need quality tools. Forget all the stuff attaching to trimmers etc.
There are two types broadly. Minimal neck turning is skimming a small amount of thickness to uniform necks to reasonable limits without causing the overall reduction in clearance to the chamber walls to become excessive. This will be for standard neck size chambers in your barrel.
The other is neck turning to a specific clearance that suits special tight neck chambers. This is for tight neck chambers. This is what your gunsmith may be building I think so therefore it will be essential to neck turn to fit a cartridge into the chamber. It is also essential that your measurements are precise as clearance in this area is critical. That will often require a step up in measurement instruments. An area beyond the Digital Vernier type calipers.

We sell all the K&M brand stuff and 21st Century stuff ourselves because we use these. There are others around also.

All these tools are often are called "hand neck turning tools" but really it is done with a slow cordless drill or cordless screwdriver. There is a bit of a technique to getting it right but it certainly is possible to turn case necks to a consistent thickness to within one tenth thousandth of an inch (0.0001") or (0.003mm). Consistency and correct clearance are essential. Therefore precise measurement is also required.

Remember also digital calipers are great and necessary around the loading bench but for this job they are not up to it. Just because they have a scale reading to 4 or more decimal places does definitely not mean they are accurate to that level. Special micrometers and or special dial gauges which are instruments rather than just tools are needed. Also the skills to use them. I don't intend to frighten you off but better to understand up front the importance of the task and correct tools required.

Neck turning case necks is just one of many case prep techniques which are part of the mix. Its all part of the fun. But this level of handloading is a step or two up so equipment and skills need to come up also.

I have a download on my website which explains to reasons and options. Go to benchrest.com.au > sales > case and bullet prep > scroll to near the bottom and you see a hyperlink "Cartridge Case techniques and why - Bench Rest Training"

http://www.benchrest.com.au/downloads/Cartridge%20case%20prep%20techniques%20and%20why.pdf

Stuart Elliott