.223 shoulder bump issue

Brian,
I don't use the Hornady headspace gauge so I can't speak for that process. But I can say based on my years of case forming for wildcats rounds in bolt guns, when you first start sizing a case the "headspace" distance will grow longer before you actually start shoulder bumping and pushing it back. If you put brass inside a steel die and it starts squeezing the diameter down first, that brass has to go somewhere and it grows in length. Keep screwing your die down until you get a true shoulder bump.
Military brass is tougher to do this because of the increased thickness. Plus it sounds like you are already bottomed out with your die into the shellplate. Hard to say without being there looking over your shoulder, but I have taken dies before and put the bottom end (the end that touches the shell holder/plate) on a belt sander before to take off some material. That allows your die to be screwed down a little further. This doesn't have to be an precision "cut". You just need to take some material away from the die so it will screw down further.
If this was a single stage press with a shellholder I would get the precision shell holders or simply take the top of the existing shell holder to the same belt sander and shorten it a little. It has the same effect as shortening up the base of your die. Just easier to modifiy a $4 shellholder than a $25 dollar die in case something gets messed up.

Again, I can't say this is your issue without actually being there. Do you have a single stage press to experiment with sizing on first before going to your progressive with the shellplate?

Steve

Do they chamber freely?
Do you get case separation?
If not, what are you trying to fix?

Sounds like you either need a new shell holder, or you can grind the face of the shell holder back a few thou. I'd place some 200grit sand paper on the bench, put some 3 in 1 oil over the surface of the paper, press the face of the shell holder which contacts the die onto the paper and move it around it a figure of 8 pattern. You could measure the shell holder height with a caliper to determine how much you're removing. Start with 0.005" and see if it makes a difference.

BrianC636 said:

the before and after measurement was longer.

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I Confused


Yours is an AR , so take 3 brass , size and see if bolt will close.

Dont let the bolt slam on the case, it will bump the shoulder back .001" maybe more.

Progressive presses may give a different shoulder set back (bump)at each station. The deck heigth should be close to .125"

There is press platform flex to consider also.

Mixed brass may give different shoulder bumps. So as much as .005" shoulder set back from the length of the chamber is not to much. Imo.

FWIW a Lee fl die does minimal sizing needed. It also will apply plenty of neck tension too. Maybe more than your looking for.

It will do fine for brass shot out of your rifle. Shot from other rifles...well maybe. That is a highly debated topic. Truth is when i was shooting 223 using range pickup brass i had no issues as long as i annealed the brass first and used cam over or fully engaged the die with the holder. Flat base bullets it a whole other story.

Its been highly debated whether a RCBS small base die is necessary too. For most cases it is not for others i cant say it 100% necessary only that it is better at brass forming. Also the small base name is a little misleading. It pushes the shoulder back more than a Lee die.

I have a RCBS small base die set in 300 BLK because it works much better at forming new brass from 223.

As others have noted the fact that your rounds are chambering and firing flawlessly is all that matters. But it doesn't mean the gage is not useful anymore. I run all my 300BLK loads through a Hornady cartridge gage to insure 100% feeding.

BrianC636 said:

I’m going to take the die to work and take about .010 off the base in one of the lathes.

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I would suggest you use a grinder, with that being said I believe grinding the bottom of the die is a bad habit. And then there is that part where you lowered the die 1 full turn; that means you lowered the die .071".

F. Guffey

Walkalong said:

Just need to make real sure the die is the issue.

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Correct , and IMHO it is not . The issue is press deflection and shell plate flex resulting in inconsistent sized cases .

243winxb said:

Mixed brass may give different shoulder bumps. So as much as .005" shoulder set back from the length of the chamber is not to much. Imo.

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Correct again , Good advice in here and I also agree .010 removal of material from the die is way to much . In fact I would not remove any . Yes you learned you had in consistently sized cases but you did not really have an issue . As another poster was suggesting . You are fixing a problem that does not exist . That is unless this is for high precession accuracy in a bolt gun then I'd want my cases sized perfect . Back to altering your die , you now will have a die that is specific to that press and that rifle and will give you trouble any time either of those things change . On the bright side Lee dies are not that expensive to replace .

If only there was a way to determine if the case was sized before lowering the ram. We all know if the bottom of the die does not make it to the top of shell holder when sizing the case has not been returned to minimum length. It helps when the reloader learns understands the die and how it operates.. for years and years I have used feeler gages.

F. Guffey

Just since no one else pointed it out....hit that gauge with some carb cleaner and a q-tip. The tiniest little spec of crud inside the gauge will give false long readings all day long. If I read correctly, you have one gauge saying good and another telling you bad, and you're chasing the gauge telling you it's bad? If you really have a sizing issue and aren't getting the shoulder moved enough.....does you AR even care? Some of mine are fussier than others. but I've seen them absolutely choke on improperly FL sized (not mine thankfully) reloads. Like rod & hammer choked to get the stuck live round out. IF you're feeding just that one rifle, and it isn't fussing, and one gauge is telling you you're good, I'd be real tempted to discount the new gauge. But I have a dozen+ .223's to experiment to see if they all tolerate it.....

I agree with @Walkalong

Before grinding on anything, try backing your decapping / expander rod out in 1/4 turn increments and check headspace again. Every time I have a situation where I’m not getting the shoulder to move where I need it this has always fixed it

Nature Boy said:

Before grinding on anything

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There is no excuse for a reloader not to know how much grinding is necessary, all we need now is someone to tell them how. Same when determining if the case was sized before lowering the ram. It is possible to remove the die with the case before lowering the ram; a reloader that can remove the die with the case installed can measure case head protrusion from the die. In the perfect world the protrusion would be .125". Anything beyond .125" is added to the length of the case from the datum/shoulder to the case head.

F. Guffey

When a case is first squeezed by the die the side was of the case are squeezed in first before the shoulder is ever touched. This causes the shoulder to bulge forward and the Hornady tool can detect the longer shoulder. If you keep pushing the case deeper into the die the die shoulder will eventually contact the case shoulder and start moving it back.

Ireload2 said:

If you keep pushing the case deeper into the die the die shoulder will eventually contact the case shoulder and start moving it back.

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I can shorten the distance from the shoulder of the case to the case head, I can not shorten the case between the shoulder of the case and case head by moving the shoulder back. Ever time I say that I also add the part; "with a die that has full case body support". I have accepted there is something reloaders do not understand about sizing cases.

And I will never understand why they are happy with the answer; 'it is all Semantics'.

F. Guffey

Walkalong said:

Just because you refuse to accept the term "move the shoulder back", doesn't mean it doesn't happen, you just choose to call it something else.

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No, I said it was impossible to move the shoulder back with a die that has case body support and for years and years I have asked someone to explain how they move the shoulder back. I understand how cool it sounds to say "I bump the shoulder back". I also understand I am suppose to know what another reloader meant when he moves the shoulder back and or bumps the shoulder back I also find it impossible to move the shoulder back.

I have moved the shoulder back on cases, in doing so I turned the case into something that looked like an accordion or a case with bellows because the devise I was using did not have case body support.

F. Guffey

Anneal the brass, then you will eliminate the spring back. As brass work hardens it resist changes. Annealing will allow the brass to flow freely. No need to trim a die or shell holder.

Walkalong said:

Then you are simply wrong.

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If it is that simple you should have no trouble explaining how you move the shoulder back. What happens to the case body when the shoulder is moved back? The outside of the can not do move down or out because the outside of the case body is supported by the die and if the case body is moved down the case body has no choice but to get thicker.

F. Guffey