Forster .223 FL die shoulder bump and die marks on brass question.

[Linko]

When the Forster FL die is setup to touch the shell holder the die sets the shoulder to spec. Correct? Does this ensure the shoulder is always correctly set? The reason I ask is being new I read a lot about shoulders being bumped back. I have not progressed to varying dimensions on my reloads yet, and dont want to be adding variables in the process.

Second question. After resizing I see slight surface marks from the resizing along the body. This I would expect from the fact the brass swelled to chamber dimension. The marks stop above the base. Why dont I see the resizing marks all the way to the base? Is that because this section of the brass doesnt swell?

 

[Pres100]

Without actually measuring your fired brass first, and again after sizing, you won't be able to tell how far your shoulder was set back (if any). Your shell holder can affect the amount of sizing depending on the height, which is why you should verify your measurements (as there can be variance in shell holder heights or how the die was cut).

Redding makes a set of shell holders that allow bump manipulation or some do their own modifications. The important thing is to understand what you are doing and measure for verification - although you can set up per die instructions and generally be ok, precision reloading is about control and consistency.

Marks during the process can be a number of things such as dirt in the dies, tooling marks, poor alignment of brass in the holder or even holder vs die alignment. Even though the dies are full length sizers, they don't necessarily work the brass all the way to the rim.

 

[Linko]

Thanks, that is good information. I want to be accurate and have consistantancy in my reloads. I will get to measuring.

I am using a Forster co-ax press with forster dies and shell holders.

See if I have the basics correct.

Once fired brass will reflect the chamber dimensions of my rifle. I record the brass shoulder to base measurement of the fired brass. Then do the same after resizing and adjust shell holder thickness accordingly to have the sized base to shoulder and fired brass dimensions equal. Thats the goal, right?

 

[Linko]

This photo shows the defined line the sizing die leaves on the brass. The left of the photo is scuffed brass and the right (or base) is unscuffed.

 

[bigedp51]

When the Forster FL die is setup to touch the shell holder the die sets the shoulder to spec. Correct? Does this ensure the shoulder is always correctly set? The reason I ask is being new I read a lot about shoulders being bumped back. I have not progressed to varying dimensions on my reloads yet, and dont want to be adding variables in the process.

Linko

We live in a plus and minus manufacturing world and each rifle chamber and die set will be slightly different. As an example I have a Lee full length die set when the die contacts the shell holder it pushes the shoulder back .011. And it also sizes the base of the case smaller in diameter than two small base dies I have. When you follow the dies instructions and the die makes hard contact with the shell holder the resized case should fit in "ANY" rifle chamber. What you need to do is adjust the die up or down until the case just fits in your chamber. Meaning .001 to .002 for a bolt action and .003 to .004 for a semiauto rifle.

Below look at the blue, red and green dotted lines and the words "shoulder setback", you will need to adjust your die for "minimum" shoulder bump or shoulder setback. This will extend your case life and prevent stretching in the base web area and case head separations.

Buy a Hornady cartridge case headspace gauge and measure your fired cases and then only bump the case shoulder back the minimum amount.

 

[chevytruck_83]

All of the above is dead on. You must measure your cases after sizing to make sure your actually sizing them. Its not unheard of for dies to bad. If you do large batches at a time like most you could end up with a hundred or so that wont chamber. As far as the scratches i would spray some rem oil in your dies and a bore mop to clean out your die. I bet its carbon in your die or a worn die

 

[Pres100]

While you are cleaning your die (or polishing lightly), go ahead and make sure your shell holder is clean and your press where the shell holder goes. This will help make sure things aren't offset from dirtor grime.
Also, when placing your case in the holder, don't rush and have it partially in - if you do it will not goings the die aligned and will scuff itself as it tries to self-align in the die.
As Bigedp51 mentioned - we live in a world of tolerances and they can stack up. No need to drive yourself crazy over things, Justdo slow and be aware.

 

[bigedp51]

Second question. After resizing I see slight surface marks from the resizing along the body. This I would expect from the fact the brass swelled to chamber dimension. The marks stop above the base. Why dont I see the resizing marks all the way to the base? Is that because this section of the brass doesnt swell?

Linko

Below are two different make .303 British cases fired in the "SAME" Military Enfield rifle, the Greek HXP case on the right has a smaller base diameter and expanded "MORE" to meet the chamber walls. The Prvi Partizan case on the left has a larger base diameter and is also over .010 thicker in the base area than the HXP case on the right and expanded very little.

Meaning the smaller the base diameter of the cartridge case the more pronounced the base expansion will appear when fired. Therefore your case in your photo is OK and normal and the die will not size down to the extractor groove.

If you have longitudinal scratches on your cases normally it means you have transferred grit from the case to the inside of the die. When this happens just polish the inside of the die with the appropriate size shotgun cleaning mop with J&B bore paste, automotive rubbing compound etc. to remove the grit and polish the die.

If the die is new then follow the cleaning instructions on the dies directions, some of the newer dies have a "dry" protective film coating that requires using what the directions call for to remove this protective film.

 

[Linko]

I will get to both measuring my fired cases begore and after FL sizing and make sure my die is cleaned. I am starting my reloading journey with ammo for my AR and mossberg bolt action before I start to load for my Savage F TR target rifle. Figure I better learn on the less expensive components before I start using my expensive Lapua brass, SMK bullets and Varget power.
Thanks much for all the guidance.
I am using imperial case wax and graphite neck powder. Is this recommended? It seems easy to clean off the brass.

 

[Linko]

When the Forster FL die is setup to touch the shell holder the die sets the shoulder to spec. Correct? Does this ensure the shoulder is always correctly set? The reason I ask is being new I read a lot about shoulders being bumped back. I have not progressed to varying dimensions on my reloads yet, and dont want to be adding variables in the process.

Linko

What you need to do is adjust the die up or down until the case just fits in your chamber. Meaning .001 to .002 for a bolt action and .003 to .004 for a semiauto rifle.


Buy a Hornady cartridge case headspace gauge and measure your fired cases and then only bump the case shoulder back the minimum amount.

When you say .001 to .002 you mean the shoulder should be bumped back .001 to .002 from the fire formed dimension, correct?

 

[bigedp51]

When you say .001 to .002 you mean the shoulder should be bumped back .001 to .002 from the fire formed dimension, correct?

Yes, on a bolt action .001 to .002 and on a AR15 .003 to .004 shoulder bump.

Below a fired unresized .223/5.56 case in my Hornady gauge

Below the same case after full length resizing and .003 shoulder bump.

Below on the right is a RCBS shell holder for the .223 and on the left is a Redding +.004 competition shell holder. With the Redding shell holder when the die makes hard contact (press cam over) bumps the shoulder back .004 "LESS" than the RCBS shell holder. Meaning if I had used the RCBS shell holder adjusted as per the dies instructions the shoulder would have been pushed back .007 and the case would have been over resized.

Below "head clearance" is directly proportional with the amount of shoulder bump and how far the case must stretch when fired to meet the bolt face. It is this stretching that causes the case to thin in the base and leads to case head separations. And when the shoulder bump is held to the minimum the elastic limits of the brass is not exceeded and the case does not stretch and the brass rebounds after firing.

Below a case being fired and stretching to meet the bolt face, and when you resize your cases with the minimum shoulder bump the case does not stretch and you extend or lengthen your case life.

Below a factory loaded once fired Winchester .303 British case and it stretched .009 on its first firing due to excessive head clearance in a military Enfield rifle.

Below a animated example of a commercial .303 British case being fired in the Enfield chamber with its "LONGER" headspace settings and excess head clearance.

 

[Linko]

When you say .001 to .002 you mean the shoulder should be bumped back .001 to .002 from the fire formed dimension, correct?

Yes, on a bolt action .001 to .002 and on a AR15 .003 to .004 shoulder bump.

Below a fired unresized .223/5.56 case in my Hornady gauge

Below the same case after full length resizing and .003 shoulder bump.

Below on the right is a RCBS shell holder for the .223 and on the left is a Redding +.004 competition shell holder. With the Redding shell holder when the die makes hard contact (press cam over) bumps the shoulder back .004 "LESS" than the RCBS shell holder. Meaning if I had used the RCBS shell holder adjusted as per the dies instructions the shoulder would have been pushed back .007 and the case would have been over resized.

Thank you. That is an excellent helpful explanation. Just one point regarding my equipment. I am using a Forster setup. So my press doesn't have shell holders. The press has the sliding plates that grip the case head. I my case it will be all about the die adjustment ring for setting the die depth to acheive the desired shoulder bump, right?

 

['Freak]

“I am using a Forster setup. So my press doesn't have shell holders. The press has the sliding plates that grip the case head. I my case it will be all about the die adjustment ring for setting the die depth to acheive the desired shoulder bump, right?“


Yes, back the die out of the ‘adjustment ring’ a fraction of a turn to reduce the amount of shoulder setback. Working with the die’s one in fourteen thread pitch, if you want to make a ~ .001” change in the amount of shoulder setback you’ll need to turn the die only 5° either further into or backed out of the adjustment ring.

Exactly one full turn will move the die .0714”, or 1/14 = .0714. An eighth of a turn moves the die .0089”, or (1/8) * (1/14) = .0089. Rotating the die 5° will get you that .001” change, or (5/360) * (1/14) = .00099, and so on.

 

[Linko]

Thank you all so much for helping. I really appreciate the very detailed assistance, and you have done it in a way that makes it easy to understand. I hope I can give back to the group soon.

I cant wait to get back to the bench !