Headspace vs setting the shoulder back

[Mainer]

If a case headspaces on its sholder, why is it advised to set the shoulder back when the case is resized? Would not a close as possible fit to chamber length be desired?

 

[RTH1800]

The shoulder bump is done to insure ease of chambering and consistency. Cases tend to grow and not all uniformly. The .001-.002 shoulder bump makes them uniform and allows smooth, consistent bolt closure. Some folks only bump the shoulder every 3-4 cycle. I do it every time.

 

[Steel head]

If a case headspaces on its sholder, why is it advised to set the shoulder back when the case is resized? Would not a close as possible fit to chamber length be desired?

Not if your gonna be out in the field with dust, mud and rain.

I’m lazy and often neck size only but I know it’s risks and am willing to accept them.

 

[salks]

Consistency. There are some good discussions on this subject in the reloading section of this forum. I had this discussion with a friend of mine who has way more experience than me. His answer was just bump the shoulder back .001 -.002. It's worked for me.

 

[spife7980]

Id say its reliability more than consistency though consistency is also a benefit. If its chamber sized what happens when a grain of sand gets in the chamber? Its now taking up space where there is none to spare.

I want my rounds to chamber reliably and not let a little dust jam it up.

 

[nn8734]

I bump .002 for bolt guns and .004 for gas guns, primarily for reliability reasons. I prefer to avoid any more stretch than that.

 

[RTH1800]

I once had a very accurate M40 A1 clone. I loaded new Lapua brass and set dies up to simply touch but not move the shoulder via graphite method. I used .0015 neck tension. Loaded the brass 50 times. Load was mid range IMR 4064 with 175 grain SMK's. It was fine but I finally retired it.
Normally I do bump .002 on bolt guns.