I’ve been reading a lot about how neck tension affects velocities and therefore precision. We neck turn, anneal and spend a great deal of time preparing brass but how do we quantify / measure the actual neck tension on the bullet? One solution I found was to use an arbor press with the force measurement option then sort the rounds based on seating force. With that idea in mind I bought a press with the force measurement option along with a Wilson Micrometer arbour seating die. I then loaded 120 rounds of 6.5CM where the brass had been annealed before neck uniformed to 0.014" and neck sized to 0.002" under. I then took notes of the force required to initiate seating and was surprised at some of the variations. The least was 10lbs and the max was 90lbs but the majority were around the 30lbs mark.
Press - http://brtshooterssupply.com.au/products/km-arbor-press.html
Force Measurement Option - http://brtshooterssupply.com.au/products/low-force-pack-for-arbor-press-km.html
Dial Gauge - http://brtshooterssupply.com.au/products/km-dial-indicator-001.html
Wilson Die 6.5CM, S/S, VLD Stem - http://brtshooterssupply.com.au/products/wilson-stainless-micrometer-seater.html
Being a nerd with a background in electronics I wanted a better way to measure the force so I purchased a 200lb load cell and a Digital display. The joy of the display / controller is that I can set a low and high alarm so I don’t need to watch a dial gauge when seating. For example on the 6.5 I can set a low of 28lbs and high of 32lbs and reject any rounds that trip the alarm. The failures can then be assessed for either annealing again or a tighter collet to size the neck.
Display - https://www.tomtop.com/p-e3684.html
Load Cell - https://au.element14.com/sensor-solutions-te-connectivity/fx1901-0001-0200-l/compression-load-cell-200lb-5vdc/dp/2717359
Now to machine a small collar and platen for the cell before calibrating and more loading.
Why do I bother you ask, I’m bored and any excuse to merge shooting with technology is fun for me