Why can't I measure shoulder bump?

[Skattergun]

I make these from a barrel drop, run the Reamer in just passed shoulder. Slot the other end and add a set screw so it mounts to your calipers. This is primarily used as a shoulder bump gauge. But also works to get a starting point for bullet seating depth.

 

[Dusty Stevens]

Try to measure the same case over and over until you get the same measurement if youre getting inconsistent measurements. I think your brass just isnt formed yet

 

[K22]

All of mine are .125

All my RCBC shell holders are the "industry standard" of .125".

I do not use Lee shell holders for sizing as they do not fit into my RCBS press. I'm required to use them with the Sinclair Priming Tool because those are the ones that are specified and fit.

My Lee shell holders differ from my RCBS in depth of cut by 0.0103", the "X" dimension illustrated in the Redding diagram on their web site describing their competition shell holders. Maybe I just got some off spec shell holders, i.e. small rifle and large rifle. Also my Lee's are at least 20 years old.

 

[BoydAllen]

All my RCBC shell holders are the "industry standard" of .125".

I do not use Lee shell holders for sizing as they do not fit into my RCBS press. I'm required to use them with the Sinclair Priming Tool because those are the ones that are specified and fit.

My Lee shell holders differ from my RCBS in depth of cut by 0.0103", the "X" dimension illustrated in the Redding diagram on their web site describing their competition shell holders. Maybe I just got some off spec shell holders, i.e. small rifle and large rifle. Also my Lee's are at least 20 years old.

Lee makes two different kinds of shell holders. The ones that you tried are for their priming tool, not for use on a loading press. They also make regular, standard loading shell holders to the same dimensions as other brands that will work in your RCBS press. I have both kinds.

 

[INTJ]

Why is it that die set up is such a polarizing subject ?

It is polarizing because most everyone took the time to thoughtfully and systematically develop their approach and they feel the need to defend it.

The truth is many different different approaches work well if they are thoughtfully developed and consistently applied. Also, while we often know "what" works, we really didn't know the "why" as well as we think......

 

[Webster]

I disagree with so much of this that it would be hard to know where to start. Instead I will relate a relevant experience. A friend was experiencing inconsistent shoulder bump using good dies and a Forster press. We were able to adjust a two torch rotary annealer to produce brass that bumped to a total variance of .001 (plus or minus half that) while retaining enough neck hardness for magazine feeding rounds loaded with heavy bullets. The calibers were .338 Lapua and 7mm WSM. For my PPC I am able to get very consistent shoulder bump without camming over, as well as for my .222 Rem. bench and varmint rifles.

On of the problems that I have see is fellows trying to bump cases that have not grown (shoulder to head) long enough to need it. I have been able to come up with a way to make an accurate die bump adjustment based on once fired brass.

Never understood camming over. Doesn't make sense to me. You can only shove the case so far into the die?

 

[Uncle Ed]

Never understood camming over. Doesn't make sense to me. You can only shove the case so far into the die?

Cam over takes all the slop out of the press and variations in shoulder location. This can vary by the type and age of the press.

The Redding Competition shell holders are a good example. You set the die up with cam over and changing the shell holders varies the amount of shoulder bump.

If you still don't understand I will sell you my 1973 Rockchucker press with its worn pins and linkages.

Bottom line, hard contact with the shell holder and cam over eliminates any slop in the press. And the amount of shoulder bump is controlled by just the shell holder and die.

 

[Webster]

Cam over takes all the slop out of the press and variations in shoulder location. This can vary by the type and age of the press.

The Redding Competition shell holders are a good example. You set the die up with cam over and changing the shell holders varies the amount of shoulder bump.

If you still don't understand I will sell you my 1973 Rockchucker press with its worn pins and linkages.

Bottom line, hard contact with the shell holder and cam over eliminates any slop in the press. And the amount of shoulder bump is controlled by just the shell holder and die.

Why wouldn't just pushing on the handle creating the force to start the case ito the die remove all of the clearance in the lnkage? Beyond that it seems you are bending something. The clearances are air gaps! No force required.

 

[edwardware]

. . . and right off the bat I suspected a problem. I am measuring up to .002 variability in fired cases to the datum line.

This matches my experience. I attribute it to brass variability.

Even with my FL die all the way down on the shell holder, I can maybe [and I emphasize MAYBE] measure .001 difference from a fired case.

Perfect! Your dies aren't excessively small, and your chamber isn't excessively large. Cam over and done!

 

[Kracken McGraw]

Why wouldn't just pushing on the handle creating the force to start the case ito the die remove all of the clearance in the lnkage? Beyond that it seems you are bending something. The clearances are air gaps! No force required.

I don’t understand it either, but I do have to screw the die past touch quite often on my RCII to obtain the bump that is needed.

 

[Uncle Ed]

Why wouldn't just pushing on the handle creating the force to start the case ito the die remove all of the clearance in the lnkage? Beyond that it seems you are bending something. The clearances are air gaps! No force required.

Some reloaders have no problem with an air gap between the base of the die and the shell holder. So again it depends on the type press and its quality.

My 1973 Rockchucker is worn and I get the best results setting the dies up per the instructions with cam over and the Redding shell holders. With the die and shell holder forced together, the press is eliminated from the equation.

Fourteen Reloading Presses Compared: Single-Stage Shootout​

https://ultimatereloader.com/2019/0...ng-presses-compared-single-stage-shootout/15/

 

[Dusty Stevens]

Most good dies do not touch the shellholder once proper bump is set. The press still cams over. Its a mechanical advantage that is consistent. The only press i have that doesnt cam over is a goofy summit press. You cant bump most shoulders with it and if it does bump its pure muscle and not consistent. It makes a good decapping press mainly because of its spent primer handling design

 

[K22]

Lee makes two different kinds of shell holders. The ones that you tried are for their priming tool, not for use on a loading press. They also make regular, standard loading shell holders to the same dimensions as other brands that will work in your RCBS press. I have both kinds.

Thanks for the clarification - that makes sense. Learn something new every day.

My apology for the original poster on this issue - I wasn't aware that Lee made two different shell holders probably because I never used any Lee products except the shell holders for the Sinclair Priming tool.

I imagine as long as the .125" dimension is maintained, it doesn't matter which brand you use as long as it fits in your press.

 

[DirtySteve]

Can we get an expert like Guffey to chime in... Lol...

 

[dogdude]

Most good dies do not touch the shellholder once proper bump is set. The press still cams over. Its a mechanical advantage that is consistent. The only press i have that doesnt cam over is a goofy summit press. You cant bump most shoulders with it and if it does bump its pure muscle and not consistent. It makes a good decapping press mainly because of its spent primer handling design

Dusty is right about good dies not touching the shellholder, my custom Whidden doesn't come close, but it bumps to the # I want.

 

[MagnumManiac]

I disagree with so much of this that it would be hard to know where to start. Instead I will relate a relevant experience. A friend was experiencing inconsistent shoulder bump using good dies and a Forster press. We were able to adjust a two torch rotary annealer to produce brass that bumped to a total variance of .001 (plus or minus half that) while retaining enough neck hardness for magazine feeding rounds loaded with heavy bullets. The calibers were .338 Lapua and 7mm WSM. For my PPC I am able to get very consistent shoulder bump without camming over, as well as for my .222 Rem. bench and varmint rifles.

On of the problems that I have see is fellows trying to bump cases that have not grown (shoulder to head) long enough to need it. I have been able to come up with a way to make an accurate die bump adjustment based on once fired brass.

Cool you disagree.
Tell us HOW you were able to get your .001”( or half that) variance.
I will say no more until you EXPLAIN what you did.

 

[MagnumManiac]

Why wouldn't just pushing on the handle creating the force to start the case ito the die remove all of the clearance in the lnkage? Beyond that it seems you are bending something. The clearances are air gaps! No force required.

So wrong.

 

[BoydAllen]

Cool you disagree.
Tell us HOW you were able to get your .001”( or half that) variance.
I will say no more until you EXPLAIN what you did.

We arrived at the amount of time in the flames of the annealer that gave that result, while preserving enough hardness in the neck so that heavy bullets loaded in magnums, fed from magazines did not move. The press was a Forster B2, Later we found that the problem returned after a couple of firings, which indicated that, going forward, we would have to anneal every other firing to keep the bump uniform. The first time we tried cases, the anneal was not enough. We added a second to the dwell time in the flames and got what we were looking for.

 

[MagnumManiac]

BoydAllen.
That doesn’t explain diddly squat as to how you sized the brass.
Anyway, never mind, I have no interest in what you to have to say.
Ever heard of a short chamber and a long die?
Doesn’t matter, ignore list you go.

 

[INTJ]

Why wouldn't just pushing on the handle creating the force to start the case ito the die remove all of the clearance in the lnkage? Beyond that it seems you are bending something. The clearances are air gaps! No force required.

Most reloading presses do seem to have some deflection and inconsistency in them. I measure after sizing each case for my LR BR rifles. That said, I know of two presses that have virtually no deflection. That is the Prazipress and the Zeropress.

I still get a little variation in shoulder set back with my Prazipress, but it is much less than with the Co-Ax and RCBS presses I have, and most likely caused by inconsistency in lubing the cases.