PDA

View Full Version : 6.5X47 Lapua neck tension logic



Cat 64
08-09-2014, 09:08 AM
Besides the problem I have listed in a thread below, I discovered that the neck tension I get after resizing is not adequate. The cases I am using are brand new Lapua (fired once). The outside diameter of a fired case is .293 (if I drop a bullet in the case at this time it will go down with a very slight pressure). After resizing I get the diameter to .289. When seating a bullet I get obvious indicators of "forcing" (i.e. hard to push, shavings at the mouth). The diameter of a loaded round is .290. The book dimensions for a loaded round (as stipulated in the Berger book...I load Berger bullets...) is .291. Question is what neck tension I will need to hone my die (I will send it to Forster and ask for this service; they have done it before for me)?

FW Conch
08-09-2014, 05:13 PM
Do you inside chamfer your case necks. I have gone to the VLD model and get no copper shaving. With only .001" difference between Barnes book and your measurement, it doesn't sound like your specs are off.

Hotolds442
08-09-2014, 07:14 PM
.003 is the norm for neck to chamber clearance, I'd say you're in spec. Make sure your seating die is not screwed down far enough to add any crimping, otherwise you could shave the bullet in the last ..002-.004 of seating as the die is trying to crimp at the same time it's finishing the seating process.
The outside diameter of your fired brass has a little springback after firing as the brass remembers it's original diameter somewhat. I really don't see an issue with the neck dimensions in any of your readings.