Shoulder bump confusion

[rr2030]

On the consistency issue: Are you annealing? That helps me with consistency.

no

 

[rr2030]

rr2030, I have no idea of your experience level, so excuse me if this is remedial for you.

Are you aware that you can screw the die down past “touching” the shell holder to get more cam over?

I am sorry, I responded too quickly. Yes I have gone past the touching the shell holder. But once all the play is taken up in the threads and various components of the press/shell holder/die I don't believe there would be any benefit/ No ?

 

[Lougler]

I bet if you lower the ram (raise the handle) and screw the die down a little more, you will find the extra .001” of bump you’re looking for.

 

[jds holler]

I'm gonna possibly agree with Lougler on this. Sometimes even with light cam-over, there is enough press flex to allow a little more length than you might realize.

This weekend, I loaded some 7 Mag for my friends rifle, and had to go to what could only be called "Heavy Cam-over" to get a sweet fit in the chamber. Can't actually say if I was bumping the shoulder, or sizing better at the case body, but it worked. Anything less, and I could hardly close the bolt. Before sizing, the cases fit and functioned fine. jd

 

[rr2030]

I bet if you lower the ram (raise the handle) and screw the die down a little more, you will find the extra .001” of bump you’re looking for.

I did that to the point I was afraid I was going to damage something. yield was .0005"

 

[Uncle Ed]

Just take a spare shell holder and lap it on some fine wet and dry sandpaper. You can buy packs of wet and dry sand paper from 400 grit down to 2000 grit. And I would start with 1000 or finer grit because you do not need to remove very much metal.

I do this on a thick flat piece of glass and wet both sides of the sand paper. The water on the bottom helps hold the sand paper to the glass. The water on top of the sand paper allows the shell holder to float and keep any metal from building up. Lap in a figure eight pattern and rotate the shell holder often. And keep measuring the thickness to ensure you are taking it down evenly.

In over 47 years of reloading I only had to lap one shell holder, and I only had to take .003 off the top of the shell holder.

That being said .002 shoulder bump in a bolt action is more than enough. And as a further example I only bump the case shoulder back .003 for my AR15 loads.

 

[rr2030]

It has been suggested that the cases being fired once since new may not have expanded fully to the limits of my chamber. Something I had not thought about. The cases, resized or once fired require minimal effort to close the bolt. With this in mind I will fire the cases a few more times and remeasure then re think the shoulder bump.

As always, the input from others on this forum transcend the typical thought process and I value every opinion here.

 

[Richard Coody]

It has been suggested that the cases being fired once since new may not have expanded fully to the limits of my chamber. Something I had not thought about. The cases, resized or once fired require minimal effort to close the bolt. With this in mind I will fire the cases a few more times and remeasure then re think the shoulder bump.

As always, the input from others on this forum transcend the typical thought process and I value every opinion here.

now you are thinking. new brass is short to fit in any chamber. usually takes 3 or more firings to fully fire form brass. you should not set up a shoulder bump on your die until then. just size the necks. simple test is when a fired and not resized case chambers with resistance you are ready to set up your shoulder bump. 1 to 2 thousands is plenty in a bolt gun.

another little hint. don't go trimming brass until fully fireformed. if you trim to the trim to length on new brass then after fireforming you will find it short.

 

[JFrank]

I am bumping the shoulder on 22-250 cases, I would like to move them .003". All my fired cases measure 1.519" so that puts me at 1.516, correct? I am using Redding competition dies with the separate body die for this procedure and the cases are lubed with Imperial sizing wax. The shell holder Lyman, is the thinest one I have for that case. So even with the die cranked down all the way to where it makes contact with the shell holder all the bump I can muster is .002" to .0025" and it differs with each case, not consistant. Where am I going wrong ? It seams so straight forward. I am using the Hornady comparator and shoulder bump gauge set to make my measurements.

The Reloader should know how to measure a chamber
As Dusty points out add a feeler gauge under the shell holder, .010 there's always a gap extend the ram then carefully by use of threads screw the Die down to touch without cam over try it again.
( it's impossible to BUMP a shoulder using a Die with full body support) however the shoulder you end up with could be different shoulder than what you started with
SPJ

 

[Richard Coody]

we all know what really happens when a case is sized is a tiny (.001 to .002) piece of case wall becomes shoulder and a tiny piece of shoulder becomes neck. the reverse on firing. over several cycles that shoulder brass migrates into the neck. that shoulder brass is thicker than the original neck a causes some issues. that is why you ocasionally have to trim your necks.

 

[JFrank]

Adding additional lube and giving a 5 count at the top of the ram travel has worked a little better. A fired not sized case easily chambers in my rifle near un noticeable difference than the sized case. As a note, performing the sizing operation exactly the same every time yield .001" to .0015" difference in length. if I didn't know better I would say Hillary is messing with me.

I think I am making this difficult. Going to set the die as I have for 15 years and pretend I never heard of shoulder bump.

Is the Reloader giving up??
Did the Reloader insert a feeler gauge under the shell holder as Dusty suggested?

 

[fguffey]

The shell holder Lyman, is the thinest one I have for that case. So even with the die cranked down all the way to where it makes contact with the shell holder all the bump I can muster is .002" to .0025"

We have members that think they understand what you are talking about. 'the thickest you have", If you had a tool that measured the height of the shell holder from the deck of the shell holder to the top of the shell holder you could determine the deck height of the shell holder. All of my shell holders have a deck height of .125". Shell holders that do not have the correct deck height are special and cost more money or the shell holder is very old; like 60 years old.

It is possible to check the shell holder and die for their ability to shorten the case from the shoulder to the case head. And there are ways to determine if the case won or the press won meaning the case can have an ability to resist sizing. When the case wins the die does not make it to the shell holder when the ram is at the top of the stroke.

F. Guffey

 

[fguffey]

After your cases have been fired 2 or 3 times without bumping the shoulder measure.them to see what your chamber is

It just does not take me that long to look at something. I measure before and again after, and I am the fan of measuring the length of the chamber from the shoulder to the bolt face first.

And then there is the fire them until they are full grown; as the case is fired and fired and fired it is work hardened, work hardening of the case increases its ability to resist sizing.

F. Guffey

 

[fguffey]

Shoulder bump confusion: I have bump presses, my bump presses are cam over presses. Reloaders assume they can move the shoulder back, not me, I find it impossible to move/bump the shoulder back with a die that has case body support.

F. Guffey

 

[JFrank]

^^^told ya

 

[Ccrider]

rr2030, I have no idea of your experience level, so excuse me if this is remedial for you.

Are you aware that you can screw the die down past “touching” the shell holder to get more cam over?

This is what I have been thinking but hesitated to raise waiting on the experienced guys to address it. I have a Forster press and can adjust my FL dies to achieve desired shoulder bump. Getting the die adjusted to .001 or .0015 is a meticulous process, but effective and repeatable once the die is adjusted correctly. I am not using custom dies-just Harrell’s and Redding.

A few pieces do brass do not size as easily or as much. I can feel the differences and use them for foulers. Annealing usually fixes this but not always. If not, I mark the brass and keep moving.
The Innovative gauge I use to measure with is very useful. I did not think it would be repeatable but it is once you learn how to use it consistently. Plus you can use it on any case and you get immediate visual feedback. Larry at Innovative is a good guy and will share info with you if needed.

I don’t see any difference between.001 and .0015 and feel that the difference in brass can cause this variation. Of course, I don’t claim that anything I say here is gospel. I am learning and just sharing what is working for me.

 

[Ccrider]

Btw, I forgot to add that I found that for my press, there is a sweet spot between cramming over and touching the shell holder. If the die is adjusted too low, it will touch and not size. As I raise it up, it gets to the place where it will cam over and size. If I continue to raise it up it gets to where it will not size again. May be different with other presses.

 

[rr2030]

What I failed to recognize was that the new cases needed to be fired enough times to stretch to my chamber dimensions, that explains why they were so short. In the past I have shoulder bumped similar cases with success but they had been fired several times before setting the shoulder back. Same thing with my .308.

So confusion set in, I assumed one firing was enough to stretch them out, never thought otherwise.

Thanks for all the input.