How to size shoulder?

M

Machineguntony

New member
How does one size the shoulder on a rifle round?

All these years, I just accepted that I didn’t resize the shoulder. But now I’m trying to do it right and size the shoulder for increased reliability.

I’m having a heck of a time sizing the shoulder of my 308 and 223 rounds.

I using an RCBs xdie. I had originally used a Dillon die, but the Dillon has the same problem.

The case does not go below the first step in the case gauge.

It’s the sizing die that resizes the shoulder correct?

I’ve turned the die down as far as possible in the press. The manual says to turn down the stem 1/8 turn until the shoulder properly sizes, but I’ve turned it down. It still does not help. Actually, too far down and it causes shoulder bulge.

I know it’s possible to size the shoulder because I got lucky and was able to properly size 100 rounds (where the round sat perfectly in the bottom step of the case gauge). But then unscrewed the die, and now I can’t get it back to sizing the shoulder.

Any advice?
 
By resizing the shoulder, are you referring to the case elongating during sizing and then requiring setting the shoulder back in order for the case to chamber? If that is the case, it sounds like the sizing die is overly long and not setting the shoulder back even after contacting the shell holder. If so, there is a cure for that. Give a more detailed explanation of what is happening.
 
I know it’s possible to size the shoulder because I got lucky and was able to properly size 100 rounds (where the round sat perfectly in the bottom step of the case gauge). But then unscrewed the die, and now I can’t get it back to sizing the shoulder.
Click to expand...

Reloaders believe they can move the shoulder of the case back, they believe they can bump the shoulder back, one manufacturer started calling one of their dies a 'bump die' and they named one of their dies a 'body die' and reloaders? They got all giggly, I insisted it was impossible to move the shoulder back on a case with a die that had full case body support, I have since changed that to; "I can not move the shoulder back on a case with a die that has full length body support".

There is something about sizing a reloader can not wrap their minds around, they do not understand they can shorten the case from the shoulder to the case head but they can not accomplish that by moving the shoulder back because; when finished the shoulder they are left with is not the same shoulder they started with, but they insist. There is a difference between moving the shoulder back and shortening the length of the case from the shoulder to the case head.

Back to the beginning; it is possible for the case to whip the press meaning the case can have more resistance to sizing than the press can overcome, that is the reason for the additional 1/4 turn of the die, 1/4 turn of the die is equal to lowering the die .017" or .0714". The additional 1/4 turn down increases the presses ability to over come the cases ability to resist sizing. And then there is that thing about checking and or determining which won, the case or the press. If I adjust my die down an additional 1/4 turn after contact with the shell holder the die should size the case and return it to minimum length/full length size. If the case is not full length sized the die did not make it to the shell holder, for me? not a problem, when that happens I measure the gap between the bottom of the shell holder and bottom of the die, the gap will indicated to me the amount of the case that did not get shoved into the die. I have options, I can screw the die down an additional 1/4 turn meaning I can lower the die an additional .017" to .034"; I could but I am not that hare headed.

It is possible to remove the die with the case before lowering the ram on most presses, for those reloaders that have the skill it is possible to measure the case head protrusion from the shell holder, in the perfect world case head protrusion from the die should be .125", meaning the die made it to the shell holder.

The deck height of the shell holder is .125, if I need to increase the presses ability to overcome the cases ability to resist sizing I add a shim between the deck of the shell holder and case head, I can add a .012" thick shim between the deck of the shell holder and case head on most RCBS shell holders.

The one thing I can not do is move the shoulder back on the case with a full length sizing die. I can shorten the distance from the shoulder of the case to the case head.

And then there is verifying, I am the fan of verifying, I can verify a Wilson case gage, I can verify a full length sizing die with the shell holder. I am the fan of new cases and once fired cases, the more a case is fired the more resistance to sizing it has. reloaders claim they neck size a case 4 times and then start over by full length sizing and I have always asked how is that possible? The case has been fired 5 times! Meaning annealing should be considered when the case whips the press.

F. Guffey
 
Seems to me the shoulder could be moved back a small amount with the brass flowing upward into the neck, even if the body below the shoulder is completely controlled/confined.
 
Seems to me the shoulder could be moved back a small amount with the brass flowing upward into the neck,
Click to expand...

I am the only reloader that can move the shoulder back a lot or a small amount. When I move the shoulder back I find the cases take on an usual appearance. When I move the shoulder back with a die that does not have case body support the case body below the shoulder starts to take on the appearance of having bellows like an accordion.

One day I decided I would sacrifice a few cases, once the first bellow started to form I lowered the handle, I formed 5 bellows.

If the die has case body support the case below the shoulder can not bulge/form bellows but I hear it everyday. reloaders claiming they move the shoulder back and or they bump it back.

F. Guffey
 
What’s going on is that my 308 and 223 rounds are not sitting below that first step in the case gauge. The result is that in my bolt guns, the bolt has lots of resistance closing. When I use new ammo, the bolt just slides close.

Also, on the rounds where I got lucky and the rounds pass the plunk test with the case gauge, the bolt closes easily. No effort at all.

I think the problem is that the shoulder is not properly resizing.

I’ve always shot 308 in my M60 and 240, which have larger chambers. So the improperly sized 308 rounds didn’t have a negative effect. But with my bolt guns, it’s a problem.

I realize that I have no idea how to resize brass properly. All these years, shooting 308 in a belt fed allowed me to hide this fact.

Now I need to learn how to resize brass.
 
I think I understand what Guffey is saying. It is true that if the die supports the shoulder and case entirely, there should be no shoulder bulge. And yes, if I turn down the stem of the sizing die too far, it creates like an accordion in the shoulder. This tells me that the shoulder is not entirely supported. I probably need a new die.

The X die does not resize the entire shoulder.

Can you recommend a die that resizes the entire shoulder?

I’m like 100% certain that my problem is that the shoulder is not being resized.
 
Forget the first step in the case gauge. The only gauge that matters is the chamber. If your sized cases drop into the chamber, you're done. Use a regular FL sizer die and you'll be fine.
"...They got all giggly..." And most are still giggling. Most of the assorted gauges and other useless stuff being sold now is about separating reloaders from their money and nothing else.
The RCBS X-die, for instance, supposedly eliminates the need for repeated trimming after an initial case trim of .020". Take 20 thou off any case and you won't need to trim. Likely be under minimum case length too. For .223, taking 20 thou off a case at max OAL will put the case 10 thou over minimum. The case will crack before it gets too long. .030" is the OAL tolerance.
 
Machineguntony said:
I using an RCBs xdie.
.
.
I’ve turned the die down as far as possible in the press.
Click to expand...

Did you thread the die body into the press until the die touched the shell holder with the press at the top of its stroke and then lower the shell holder and turn the die in another 1/8 to 1/4 turn?

Did you back the mandrel out 1 or 2 turns for the initial resizing of the brass, so the “X” feature was not in play, and then trim the resized brass?

Then did you take one of the initially sized and trimmed cases and load it and fire it and use it to adjust the mandrel for future resizing of that batch of brass?
 
The RCBS X-die, for instance, supposedly eliminates the need for repeated trimming after an initial case trim of .020".
Click to expand...

If he failed to trim the cases .020" in the beginning he could be having problems because the X die is a collet type die but he claimed:

I using an RCBs xdie. I had originally used a Dillon die, but the Dillon has the same problem.
Click to expand...

The first time around.

F. Guffey
 
I am going to try to simplify this.

I have a steel micrometers.

I have a Hornady shoulder comparator gauges and the adapter that goes on the micrometer. .

I take the steel micrometer, but on the Hornady setup (adaptor and the shoulder die) and I adjust my FL size die down until I get a .002 or so shoulder bump shorter than the measured shoulder before I start to do it.

Yes its a bit of fuss, sometimes I go to far, sometimes not far enough.

When the shoulder is bumped back .002 or at least .001, I am happy and I quit.

I don't get bellows. But I use a FL die, I don't have a chamber gauge. I have a rifle chamber and if it fits in that and extracts its the right length (or close enough).

If it fits and does not extract, something has gone wrong, I have knocked the shoulder back a clot further than I thought (aka got mixed up with numbers)
 
Machineguntony:
OK, now we are getting somewhere since you are aware that the sizing die needs to be turned down farther. Here is my solution that I have applied to at least a half dozen sizing dies. However, you may not like the sound of it. Remove the decapping stem from the die and grind or file off some metal at the die mouth opening until proper sizing and shoulder set back can be achieved. The easy and quick way to do that is with a small grinding wheel attached to an electric drill. Lacking that, a file can be used. Now some may say that is ruining the die, but not so in the least.

Others may say to grind down the shell holder but that could weaken it.
 
Sometimes the the thing that you think is causing the problem is not what’s causing the problem.

Took three hours, but I figured it out.

I’m loading on a 1050, turns out that the swage station was over swaging the brass and causing the bulge. I didn’t think that the swage station could be causing the problem, so I wouldn’t gauge the brass until it reached the powder charge station.

Tonight I decided to gauge each case after each station. After the sizing station, the brass fit fine on the bottom step! But after the swage station, it no longer fit the case gauge on the bottom step.

By releasing some swage, the brass fit case gauge again, perfectly.

Now the finished 308 round is passing the gauge and closing on the bolt like butter. And it’s passing the plunk test on an M60 barrel. Usually I have to shake the M60 barrel to get the round to fall out; now it just falls out when I turn it upside down. This will hopefully help with reliability.

Beautiful.

So to go back to the beginning of this issue...All these years, I just assumed having a tight closing bolt was normal for reloads. I was at the range, and I let this older gentleman shoot my silenced 308 rifle, as he had never shot one. As he loaded up a round, he asked, ‘why is your bolt so hard it close?’ Again, I just assumed it was normal for reloads.

He said, that’s not normal, you need to bump the shoulder. This gentleman taught reloading classes and gave me a little lesson on the spot on what to do.

All these years, I’ve been doing it wrong.

I learned something new today.
 
The manual says to turn down the stem 1/8 turn until the shoulder properly sizes, but I’ve turned it down. It still does not help. Actually, too far down and it causes shoulder bulge.
Click to expand...

It is impossible to bulge the case at the shoulder, above the shoulder or below the shoulder when sizing a case with a full length sizing die. The full length sizing dies is designed to return the case to minimum size, length and diameter, that is what It means when the die is a full length sizing die.

And then I have to ask; what were you swaging? If I swage I swage first.

And then there is crimping, now crimping can be a bad habit if you are talking about bottle neck cases but you are using a 1050 with all of those extra stations.

F. Guffey
 
The manual says to turn down the stem 1/8 turn until the shoulder properly sizes,
Click to expand...

Die instructions suggest screwing the die in an additional 1/4 turn, I would not suggest the primer punch/sizer ball assemble be screwed down an additional 1/4 turn on most dies, I have seen many dies with bent primer punch/sizer ball assembles, I have made shop calls in an effort to help a builder/reloader with problems. One had a gap of .037" between the bottom of the die and top of the shell holder with the ram up. The problem was worst than it appeared to be because he was using a cam over press meaning there was an additional .012" that was not registering.

F. Guffey
 
Machineguntommy,

Glad you found it. The swaging ram must have been trying to push up past the radius shoulder. That would not only widen the head, it would tend to push the floor of the primer pocket forward if it went in deeply enough. This is a good heads-up for other 1050 owners that it is a very strong machine that can move brass around pretty easily. For that reason, when you set one up you want to confirm the setup for each stage of operation by doing just what you did, and that is to check what each stage has done, exactly.

I use a Dillon manual swager, which has the same ram profile as the one on the 1050. I observed early on that even when you aren't driving it in too deeply, the perimeter of the primer pocket is expanded enough to raise a shallow crater wall around it. You can see this by placing some sandpaper on a flat surface like a piece of plate glass, and then rubbing the head across it. Before swaging you get relatively even marking of the head by the sandpaper. After swaging you see where it has marked a raised ring around the primer pocket distinctly. That raised area flattens back out against the bolt face upon firing, but in a few cases that has pushed enough brass back in around the pocket that a second swaging was needed for primers to fit smoothly.

You're not going to have that that primer problem with the 1050 because it swages every time you load, but I mention it to point out that the brass will flow such that after the second reloading cycle the swage won't be moving metal anywhere any longer. It'll wipe a little carbon along the sides of the primer pockets, but that's about it.

One other thing for you to check is primer seating depth is seating primers below flush with the head by about 0.004". That's a typical value for proper bridge setting on primers. If you want to get more exact, measure the primer pocket depth on your cases and get an average. Then measure, gently, the height of your new primers from the anvil feet to the bottom of the cup. Subtract the primer height from the pocket depth and add 0.003" to the result. That's how deeply your primers should be below flush with your case heads when the machine is properly set up.

BTW, the best way to measure primer pocket depth is not with a caliper depth probe. It's very hard to keep those square enough to the case an primer pocket bottom. For LR primer pockets, measure the length of your case and the length of a 3/16" pin gauge, then measure the combined pair with the pin inserted into the primer pocket and subtracting that last result from the sum of the first two measurements. That produces more consistent results. A depth micrometer with 3/16" probe will also do a good job on LR primer pockets. A 5/32" gauge or probe is needed for small primer pockets.
 
You must log in or register to reply here.
Back
Top