Case neck mouths thickening?

[R.A.W. Outdoors]

284 Winchester made from 6.5 lapua brass

K&m expanded necks
FL resized
Fire formed
Inside reamed
Fl resized
Vld deburred
Then fired again but after firing the necks open up but a bullet wont fall freely into the case, seems like every time i shoot the rifle i need to inside ream the case mouth there is no doughnut forming yet in the shoulder but its tight right up at the mouth. The inside reamer takes exciss material off every time. Is this normal ? Should i keep inside deburring every time untill my bullet falls into neck freely on a fired case?

 

[yodave]

what is your powder load and bullet combo? you may not have enough pressure to expand the neck fully to the chamber walls when firing. What was the specifications of your reamer and what does the outside diameter of a loaded round measure at the neck where the bullet is?

 

[Mystic Precision]

Consider outside neck turning and annealing. What is the chamber neck diameter vs your loaded rd diameter?

Clearance, or lack thereof, is the number 1 issue debugging customer rifles. lapua brass is very thick.

Jerry

 

[R.A.W. Outdoors]

load is 48grs h4350, 195 gr berger, seated 2.551" to ogive. 6 thou into lands velocity is 2560fps

Chamber is .317 nk

I am using a .311 bushing

I can't recall loaded round diamiter but will check and get back

 

[yodave]

load is 48grs h4350, 195 gr berger, seated 2.551" to ogive. 6 thou into lands velocity is 2560fps

Chamber is .317 nk

I am using a .311 bushing

I can't recall loaded round diamiter but will check and get back

6 thou neck tension is huge.......maybe step up to a .314 bushing

 

[R.A.W. Outdoors]

Once my expanding mandrel goes through it expands it back out. Once again i cant quite remember to what but will check later.
Tension is definitely not an issue they seat very easy almost to easy i had a few actually push in when I chamber them they are quite loose in there. This is a hunting rig that needs to feed from a mag

 

[308BAR]

Maybe the case neck is work hardened and need to be annealed?

 

[Mystic Precision]

load is 48grs h4350, 195 gr berger, seated 2.551" to ogive. 6 thou into lands velocity is 2560fps

Chamber is .317 nk

I am using a .311 bushing

I can't recall loaded round diamiter but will check and get back

Check the loaded rd diameter and ensure it is 311" or smaller in diameter. I suspect it will not be so outside neck turning is critical.

Jerry

 

[R.A.W. Outdoors]

Ok so a loaded round is .3115 or .312 depending on pressure i put on the caliper. I will try annealing this next set of rounds and see if i fix the issue. What do you think about annealing do it after the case is fired or after it is FL resized just before loading?

 

[yodave]

anneal before you size.

lapua cases have more case capacity then winchester cases, I think your load is good and on the light side of pressure hence the neck not opening up.