Best way to straighten crooked necks after necksizing
I am new to reloading and am currently reading all info I can find concering necksizing .308. I've found a tool to check neck runout... but what is acceptable?
I've experienced quite a bit of resistance when withdrawing expander ball back through case after neck sizing. I've measued neck tension after seating bullet to be ~ .002. I am wondering if expander might be a bit too large or possibly too rough on inside of neck causing shoulder distortion of my once fired brass. Or perhaps too much resistance when seating bullets due to roughness of inside of neck. 80-90% of rounds chamber but rest chamber hard and are difficulut to extract. These bullets exhibit scoring just forward of case neck. What is best way to proceed.... pull the bullets remove expander ball from die and FL resize to correct? Polish expander ball, lube inside neck? Any advice would be appreciated.
Best way to straighten crooked necks after necksizing
It's hard to get an accurate read on case necks. In theory, a fired case comes out of the chamber perfect but in practicality if you get .0005 to .001 runout on a fired case you've got a good chamber. When you resize, you have the die, press, as well as variation in neck thickness working against you. So, for me, if I come out of resize, either neck or full length, and bullet seating with less than .003 runout measured at the ogive of the bullet, I am a happy camper. Others may have tighter tolerances, but in my experience this is a practical goal.
Resistance coming back over the expander is common due to the die over squeezing the neck. The die maker has to ream the die to match a variation of neck thicknesses, say within .002 from one brand or lot to another. What you are experiencing is common. I like a dry graphite lube inside the neck that I sparingly apply with a Qtip. Makes a huge difference. Your .002 neck tension seems perfectly acceptable to me.
One thing that might help you, in case you didn't know, is to remove the little clip that holds the shell holder into the press ram and replace it with an o-ring that fits around the outside of the ram. This allows the shell holder to slide back and forth a little when you resize a case. Also, run the decapper/ expander rod a little loose by not tightening the jam nut. Sometimes, this will buy you a little more concentric output.
Usually if I am having difficulty closing the bolt and extracting, I full length resize to bump the shoulder back, say .002. Usually takes care if it.
Could the "scoring" you are seeing on your bullet be because they are seated a little long and are jamming into the lands of the rifling? Might try to seat just a 1/4 turn deeper on your seating die and see if it goes away.
Let us know how you make out. Good luck and stick with it. It can be frustrating but don't give up. You'll get it!
Edit: wow, I am a slow typer and you got some good advice above while I was pecking away!