Brass not sizing to spec

[dreyna14]

Brake cleaner and air hose. A granule of sand can cause problems.

Or just.take the die apart and clean it.

I took apart the die and cleaned it with a bore brush and CLP. No change.

[nedro]

So, what is too big/long?
Length?
Width?
Shoulder?

[dreyna14]

So, what is too big/long?
Length?
Width?
Shoulder?

I compared the new pieces to an old test dummy:

Neck OD, dead nuts
Base OD, perfect
OD at base of shoulder, good
Length to shoulder, +.004.

So that appears to be my issue. I have a surface plate and can remove .004 off the base of the die to bump the shoulder down more but I see no reason there should be any difference from past loadings unless the die wore out? Seems unlikely with ~3k pieces though it but I'm sure crazier things have happened.

[FLIGHT762]

Take the decapping spindle out of the die and size a case without it installed.

On rare occasion, the decapping spindle gets set down too long and the expander button hits the inside of the bottom of the case and won't let the case resize properly.

Your decapping pin shouldn't protrude out of the die more than about .200" max.

[divingin]

Length to shoulder, +.004.

So that appears to be my issue.

Lube a case. Run it into the die, handle fully down. Put a flashlight behind the ram, and see if there's a gap between the die and the shellholder. Alternatively, use feeler gauges to see if there's a gap.

If there is a gap, that's your problem. Two likely causes: insufficient or ineffective lube on the cases, or the die is not screwed down far enough to compensate for the press frame distorting under load.

For the first, try a drop of transmission fluid smeared over the case to test whether it's lube related (I'm not suggesting this as a solution; this is a test. Use a bunch and don't worry too much about shouder dents and the like.) Use the base to datum measurement (or whether or not it drops into your chamber) as a guide to see if it corrects the problem.

For the second, move the die down (with no load) as far as the gap was with the brass run into the die. Add a thou or so to make sure. Size normally, and check it in your chamber.

One other note: Well used brass gets resistant to changes. Most people figure that running the handle down and up as fast as possible is good enough; you may, however, get different results by pausing for a few seconds with the brass fully inserted as this allows the brass to take a set.

Marking up a case with a sharpie and working it in the chamber a few ties should show you where the case is dragging, just in case the base-to-shoulder length doesn't correct it.

[dreyna14]

^^I have adjusted the die to pretty extreme setting with no difference. I tried sizing pieces with no recapping pin with no change. The pause method might be worth a try.

The only other thing I can think of is that the die is sizing correctly, however, the pin is dragging too much and pulling the shoulder out of spec when it sizes the throat. I've made sure everything is properly lubed. If this is happening, I would expect that the shoulder angle would be different. I would have to put two different cases on something like an optical comparator at my work to see if this is happening.

[M1NM]

Only material difference between then and now is the press.

Are you using your old shell holder too? I'd be tempted to set up your old press and see if that fixes your problem. It's the only thing that has varied from your successful reloads. I have well over 10,000 rounds through some of my non carbide dies and they aren't worn out.

[dreyna14]

Are you using your old shell holder too? I'd be tempted to set up your old press and see if that fixes your problem. It's the only thing that has varied from your successful reloads. I have well over 10,000 rounds through some of my non carbide dies and they aren't worn out.

I sold the old press and I'm using the correct Lee shell holder, only one I've had of that number. I also tried a Hornady shell holder and also the shell plate when I tried the die on my progressive press.

I think I may put this thing on my lathe and stone the base down a few thou until they chamber in both of my guns.

[FLIGHT762]

Taking .005"-.006"off of the shell holder will work. It's cheapest way to do it.

This way, you don't change the die. I still think there's something off since you used this die in the past and it bumped the case shoulder fine.

You can skim the base of the die, but the shell holder way will work. Just mark that shell holder. I have one I sanded -.005". I have it marked with red magic marker.

A few months ago, In the 4+ decades of reloading, I had to send back a new die to the manufacturer to have them skim the bottom of the die since it wasn't bumping back.

They skimmed it .008" and sent it back. Die works perfectly now.

[xfer42]

I had a Loadmaster setup and 3 sizing RCBS dies (1 regular, 2 small base) that wouldnt resize right. At least 1 in 10 would lock up and stick in an AR. It was a problem on 2 other ARs and a bolt action, so I pretty much knew that it wasnt resized all the way. I got to the point I was flexing the hell out of that press to try to ram it up in a tad more. I think that exacerbated the problem. I even broke the ram once doing that. I knew either the shell plate was too thick, dies were too long, but I wasnt about to start grinding. It was one of many issues with that setup. The cases would rarely sit flush in a case gauge.

Bought a dillon and the same dies resized the cases below flush on the case gauge. Havent had a resizing problem since. I guess I could have tried replacing the shell plate, but I was done with it.

I had over 1k not so reliable rounds. I thought I could shoot them, but it was too embarrassing. I ended up using one the dies that was slightly damaged, plunged an endmill through the top to open it up for the bullet, and resized the rest of the loaded ammo on the dillon (steel pipe on top of the die as a blast shield).

[divingin]

^^I have adjusted the die to pretty extreme setting with no difference.

Have you looked for the shellplate/die gap? That alone will tell you if the die is too long to size sufficient to your needs. No gap means you're sizing to the limit of the die/shellplate combo, and will need to modify or change parts (I don't like modifying parts unless I have to.)

The only other thing I can think of is that the die is sizing correctly, however, the pin is dragging too much and pulling the shoulder out of spec when it sizes the throat.

Does removing the expander ball and decapping pin yield brass that fits the chamber? If it doesn't, that's not your problem.

In either case, marking up and chambering the brass will tell you if that's where the problem lies. And point you to where it does lie if it's not there.

I've made sure everything is properly lubed.

Do you lube the inside of the neck? That will reduce the expander ball friction as it comes back up through the neck, and minimize drag-induced distortion.

How much and what lube do you use?

As an aside, and IMO, "sufficient lube" can only be ascertained once you get usable brass out of the back end of the process. Until you get the process working, that process is all still suspect.

[dreyna14]

Have you looked for the shellplate/die gap? That alone will tell you if the die is too long to size sufficient to your needs. No gap means you're sizing to the limit of the die/shellplate combo, and will need to modify or change parts (I don't like modifying parts unless I have to.)

I verified that the gap is zero just a the press came over. I cant get things any closer together.

Does removing the expander ball and decapping pin yield brass that fits the chamber? If it doesn't, that's not your problem.

In either case, marking up and chambering the brass will tell you if that's where the problem lies. And point you to where it does lie if it's not there.

I haven't gotten a chance to mark a shell casing and see where the interference(s) are. I have a couple other ideas, too.

Do you lube the inside of the neck? That will reduce the expander ball friction as it comes back up through the neck, and minimize drag-induced distortion.

How much and what lube do you use?

As an aside, and IMO, "sufficient lube" can only be ascertained once you get usable brass out of the back end of the process. Until you get the process working, that process is all still suspect.

I use the Franklin Arsenal spray case lube. Has always worked well on all three rifle calibers I shoot. It feels like the amount is appropriate. I try to get some in the case mouths and I will give a squirt into the bottom of the die every 30-40 pieces in case I have a piece that didnt get any into it. This process has deemed to work. For the testing I've been doing the past few days I've been using One Shot on individual cases because it's easier and less messy.

[ar15barrels]

I compared the new pieces to an old test dummy:

Neck OD, dead nuts
Base OD, perfect
OD at base of shoulder, good
Length to shoulder, +.004.

So that appears to be my issue. I have a surface plate and can remove .004 off the base of the die to bump the shoulder down more but I see no reason there should be any difference from past loadings unless the die wore out? Seems unlikely with ~3k pieces though it but I'm sure crazier things have happened.

Most people don't realize how much a press frame stretches from SIZING and make an assumption that if the die is touching the shellholder WITHOUT a case in the shelholder that the die is STILL touching the shellholder WITH a case in place.
This assumption usually proves to be wrong.

Before you remove ANY metal, put a case in the shellholder and run it up into the die and take a flashlight and check for a gap between the shellholder and the base of the die.

Changing presses will change how much press frame stretch you are getting.
So with the same setting as far as how much the die is touching the shellholder, the press with more stretch will require the die to be touching the shellholder MORE to account for the extra press frame stretch.

The solution is to screw the die down 0.004" more if that's what you have measured the problem to be.

As to know HOW FAR 0.004" is, try this:
Take a piece of masking tape about 3" long.
Lay a mm scale next to it.
Make 1 mm hash marks on the tape.
Now wrap the tape around the THREADS of the die, above the lock ring.
Make a mark on the lock ring that you can see while looking at the 1mm scale on the tape.
As you adjust your lock ring, each 1mm mark that you pass will equate to 0.001" of die adjustment up or down in the press.

[ar15barrels]

I verified that the gap is zero just a the press came over.
I cant get things any closer together.

WITH a case in the die or WITHOUT a case in the die?

[dreyna14]

WITH a case in the die or WITHOUT a case in the die?

Both. There is complete contact between the shell holder and the die.

I ended up just knocking off .005" off the bottom of the die and sized a dozen cases. All chamber without issue. I guess I'll just resize all the prepped cases I have now and then pick up a new dose set when they become available.

Thing is, I want to know why things changed. Bugs the crap out of me.