Hi Guy's What is your opinion on neck turning the outside of brass and or reaming inside, is doing both over doing it. Would doing both increase accuracy beyond just one or the other? I have the Wilson trimmer and have seen the Wilson reamer. I also was looking at the k&m neck turner kit as an option. I need some feed back on tuning my loads for benchrest. I am only using Lapua brass. Thanks Peter Merriman |
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
Every shot pleases somebody..........
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In reply to this post by Peter Merriman
There are a few more things to consider. If your chamber has a tight neck then turning is mandatory. Also if you plan to neck-size your brass rather than full length size then I consider turning is advantageous. My preference is to full length size every firing which allows a bit of neck wall thickness variation to be tolerated.
Probably the most important step is to check your new brass with either a neck concentricity gauge as made by Redding or with a neck wall micrometer as made by K&M. I grade out those cases with more than 0.0015" variation and identify them with a file nick in the rim. These are used for foulers and sighters. Normally Lapua cases would only have 5 to 10 such in every 100. Some other brands can have surprisingly good consistency in certain batches. All Redding, K&M and Lapua products are available from Pro-Cal (03-52811380). Pete van Meurs |
In reply to this post by Stuart Elliott
Thanks Stuart,
The first barrel for this rifle will be standard neck size. I will look through the information provided. Thanks for the insite. P.S you won't scare me away, I enjoy it to much. |
In reply to this post by Pete van Meurs
Thanks Peter.
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