I have a new Redding Type S bushing die. My 308 loaded rounds measure 0.335 OD of the neck so I purchased a 0.334 and 0.333 bushing. When setting up the die I was able to achieve 0.001-0.0015 shoulder bump and the sized OD of the neck was 0.334. However that was with a case that had just been shot and lubed. Now I just annealed 300 pieces of brass and my sized OD of the neck is a consistent 0.332. Same lube, bushing, brass, etc. The only thing that changed is that the cases were just annealed and allowed to cool to room temp. So what makes the bushing size smaller on an annealed case versus non annealed case?
top of page
bottom of page
Yeah that shouldn’t be happening. You can also call customer support they would probably know more on that issue. Otherwise the last thing I could guess is your measuring is off because micrometer is the most accurate way to measure neck OD but those are pricy. I mean calipers get the job done but you also want to use a good brand
Well, the simplest way to put it is there is no spring back to the brass once annealed correctly. It’s basically like a stress reliever within the molecule makeup of the brass when you anneal it. When you resize and fire the brass and don’t anneal, there is this phenomenon called “worked hardening”. And when resizing the brass again but without relieving the stress through annealing, it will have more spring back properties making the OD larger using the same setup than with it annealed first. This is why annealing will give the most consistent results after every firing.