FL size, neck size only or .001 shoulder bump?

[jlvandersnick]

I'm finding that in some of my rifles I seem to get better LR (800 yds +) groups with just doing neck sizing. I recently read a thread where some seem to have good results with neck sizing only until the fired brass no longer fits into the chamber (4-6 firings)....at which point the reloader then needs bump the shoulder back . I have also noticed that I have to reduce the powder charge by about 1% on options 1 and 2 below especially option 1.

So the question is.... what are the advantages to:
1. neck sizing only as long as one can still close the bolt with reasonable effort.
2. FL sizing, but only bumping the shoulder back .001 each time OR
3. FL sizing to SAAMI spec each time (except the neck)

Assume on all options that bushings are used on necks to get .001 to .002 bullet tension. I generally use Norma and Nosler brass. Calibers are 6XC, 6.5 Rem Mag., 7 Rem Mag and 7 RUM.

Thanks
Jerry

 

[el matador]

I would avoid option #3 if possible. It will work the brass more than necessary and result in 2 things: More case trimming required, and fewer firings before case head separation.

The advantages to #1 are:

Brass fits chamber more closely.
Least amount of working the brass.

Advantages to #2 are:

More consistency across all firings since shoulder is bumped every time.
More reliable and consistent chambering of cartridges.

With match quality chambers and proper FL sizing you are not working the brass very much. This is my preferred method. A lot of factory chambers are more roomy though, and you might see greater benefits from neck sizing. I would do what works for you.

 

[jlvandersnick]

I would avoid option #3 if possible. It will work the brass more than necessary and result in 2 things: More case trimming required, and fewer firings before case head separation.

The advantages to #1 are:

Brass fits chamber more closely.
Least amount of working the brass.

Advantages to #2 are:

More consistency across all firings since shoulder is bumped every time.
More reliable and consistent chambering of cartridges.

With match quality chambers and proper FL sizing you are not working the brass very much. This is my preferred method. A lot of factory chambers are more roomy though, and you might see greater benefits from neck sizing. I would do what works for you.

thanks
unfortunately I'm not sure I have "match" quality chambers....maybe on the XC and the RUM...how does one know?
Also, does option 1 result in the neck thickening quicker than option 2? seems like I read that in another thread

 

[ShtrRdy]

My friends who do benchrest competition will neck size and then a very slight resize.