Shoulder bump with Forster Bushing,Bump, neck sizing

[bob4]

I'm sure I'm missing something simple:I decided to try shoulder bumping 300 WM. The instructions say:
"By removing the neck bushing, the Bushing Bump Neck Sizing Die may be used to bump the shoulder without changing the case neck diameter. This action maintains proper headspace in any chamber, be it custom or factory." Is this the only way to bump shoulders? I mean is it another process then put the bushing back in for the neck? Every attempt I made to not have the shoulders move yet has them set back another .003.
All my once fired cases measure 2.270 (Datum line) They still chamber effortlessly in the rifle. So I'm thinking I don't want to bump them yet. The only thing that has left headspace where it was, was actually backing the die out about 1/2 turn. Now the neck did resize doing this. Just not sure if it's correct /safe. Any guidance sure appreciated.

 

[ShtrRdy]

I haven't used that exact type of die but I think you should be fine doing what you described last. Backing the die out 1/2 turn and using the neck bushing. That should be okay.

 

[bigedp51]

I have a Forster .223 bushing bump die and any die can be adjusted up or down to adjust shoulder bump.

Simple adjustment, remove the bushing, then place a case in the shell holder and raise the ram. Now screw the die down until you feel it touch the shoulder and then back the die off "slightly" so it does not touch the shoulder. Just remember the older the sized case is the harder the brass becomes and will spring back more after sizing.

Also remember when using the Hornady cartridge case headspace gauge you measure a "fired" case and then adjust the die for .001 to .002 shoulder bump. Meaning "your" die is not that far off of minimum shoulder bump.

Chambers and dies vary in size and if you adjust the die per the instructions there is always a chance the case shoulder will be pushed back too far.

Remember you are sizing a belted case that headspaces on the belt and not the shoulder. And to extend case life it is better to headspace off the case shoulder.

Example below is a new unfired rimmed British .303 case in a Wilson case gauge. And the case shoulder is far below the chambers shoulder location and dropped far into the gauge.

Below is a fired case in the same Wilson case gauge. And the amount the case is protruding from the gauge shows the true location of the shoulder of the chamber.

Rimmed and belted cases date back to time when manufacturing was not at the modern standards today. On top of this the British developed the belted case and were using cordite powder. The cordite powder looked like long strands of spaghetti cut to just below the cases shoulder, and was placed in the case "before" the case shoulder and neck were formed.

Bottom line, the case shoulder location was not critical on rimmed and belted cases. "BUT" today you are better off letting the case headspace on the shoulder and not the belt or rim. And your die is if if adjusted as per the instructions is only .001 more shoulder bump than you may need.

And Redding makes Competition shell holders so the die still makes hard contact with the shell holder and not push the shoulder back too far. (subliminal suggestion)

 

[bob4]

Thanks to you both. Very well explained.

any die can be adjusted up or down to adjust shoulder bump.

This can save a few bucks. Is there some point backing off the shell holder is to much and not resizing enough of the case. I'm guessing this close to the case head is minimal movement.

And Redding makes Competition shell holders so the die still makes hard contact with the shell holder and not push the shoulder back too far. (subliminal suggestion)

I have a Dillon 550. Don't think a different shell holder would work.

 

[bigedp51]

Is there some point backing off the shell holder is to much and not resizing enough of the case. I'm guessing this close to the case head is minimal movement.

Before I had the Hornady cartridge case headspace gauge I would use feeler gauges to adjust the die downward. I would start with a .010 feeler gauge and work down with thinner gauges until the case would chamber freely without bolt closure resistance.

Now I just measure a fired case with the Hornady gauge and set the die for .001 to .002 shoulder bump for a bolt action.

Again chambers and dies vary in size and when the die is adjusted per the instructions the case shoulder will normally be bumped back more than .001 to .002. And small base dies will reduce the case diameter approximately .003 more than a standard die. And this same small base die will also push the shoulder back .003 more than a standard die. Meaning size the case to minimum SAAMI dimensions. "BUT" nothing is written in stone, I have a standard Lee .223 full length die that will reduce the case dimensions more than my RCBS small base die. And this same Lee die can push the shoulder back .007 if it contacts the shell holder.

 

[bob4]

I'm using Hornady HS gauges. From all I've read this is how I went about it. Removed the firing pin from the Rem 700's. Zero resistance on the bolt. With some new Norma brass case showing fair amount of resistance @2.040 I took it down until there was zero resistance. Took another case made the bump just .001 longer and now have minimal resistance. So went back down .002. Think I should be there. It was time for new brass so that's what I had that I new wasn't over worked. It'll be interesting to run this again after I fire a few. If I've done anything wrong let me know. Really appreciate all the help.