neck turning question

[bobcat93]

So I am having a rifle built in 223 improved 40° shoulder with a chamber neck dia. .245"
I need to turn necks and fire form. The gunsmith said turn necks then fire form.
After fire forming the neck shoulder junction will be moved out more onto the new shoulder and I wouldn't need to worrie about the donut forming.
What is the best way for me to do this?
..is it posable to take a 223 rem case fully sized with a bushing die to tighten up the neck to say .243 dia. Then use the corn meal method to fire form. Then full size in a 223 improved die. Then turn necks? ..
Or do I follow the smiths advice and just turn down the neck on the 223 rem brass and fire form.
Also this is the first neck turning I have done if my neck chamber is .245 dia. What should my loaded round measurements be
Thank you

 

[mikecr]

I would follow the gunsmith's advice. It's easier to turn necks while they fit your turning mandrel best.

Zero clearance = .224 + [10.5thou] x2 = .245 loaded
Turn to the thickness [] that will leave the loaded clearance you want.

 

[Alex Wheeler]

Will your shoulder be moving forward on this case or just changing angle? I believe the neck stays the same length on the 223 ai. If so, just full length size the base with the expander removed from the die, expand the neck with the corresponding expander that goes with your turning mandrel. Lube the neck and turn into the shoulder just a touch, done. If you have a .245 neck I would shoot for a .242-.243 loaded round measured at the pressure ring of the bullet. I have found no accuracy in tighter clearances.

 

[bobcat93]

Thanks guys, I should recive my neck tuner this week from Sinclair international and want something to do while my gun is away and the temp out side is to cold for my shooting taste. So I will mess around with turning case necks..
Do you anneal your brass? I do.. Is it better to anneal before turning necks or after..
Thanks

 

[mikecr]

I anneal shoulders/necks prior to improving. This, well after turning.