FL sizing die question

[Jbordi]

After FL sizing my rifle case, the shoulder measurement is actually longer then the fire-formed measurement. I am using a Hornady headspace gauge. Any ideas? Would it be a good idea to bump the shoulders back (about .002" from the fire-formed measurement) using the die with the expander ball removed? Same results with FL die is set up to touch the shell holder or with a gap at shell hoder.

I don't plan to use neck sizing dies.

 

[kansasvet]

Give us some details on rifle and caliber, it may help with figuring out the problem. Is it a custom or factory rifle?
Typically when you full length it will push the shoulder out longer until your properly adjusted die comes in contact and puts it back where it belongs.
Will your resized cases go into the chamber?

 

[Jbordi]

270 win. in factory Rem. 700 rifle. Winchester brass-RCBS die. Is it possible for the case to stretch that much after the expander pulls over it? Yes the case does fit in the chamber, but with a stiff bolt.

 

[nhkuehl]

Full length sizing

Forgive me for asking, but do you pre-lube the expander ball and lube the inside of the case necks before sizing? Also, if your press cams over you may want to move the di lower to fully contact the shell holder at the top of the stroke. All shell holders are not created equal either. nhk

 

[Jbordi]

Good question. I do role a brush on the lube pad before inserting the brush in the case mouth before sizing. I don't lube the expander ball? Die is set up to contact shell holder.

Is there a special type of lube to use on expander balls or case necks?

Thanks.

 

[abintx]

Jbordi ...

Would it be a good idea to bump the shoulders back (about .002" from the fire-formed measurement) using the die with the expander ball removed?

A big YES! Put that expander ball in a drawer. They're never used in "B"enchrest. The Full Length bushing die, which adjusts neck tension, can improve accuracy even in a hunting cartridge. It's a tuning tool that incorporates the benefits of both neck sizing and full length sizing. Check it out.

 

[Wayne Shaw]

The expander button could pull the case back out, but I think your die is a little too deep. If you're making contact with the shell holder and still not bumping the shoulder, you need to grind the top of the shell holder. The brass will get longer before getting shorter (bumping the shoulder) while sizing. As said, take the expander out, check if it's still the same. If it is, grind down the shell holder so the case goes in farther.

 

[Boyd Allen]

Wayne is spot on, but I would add one more thing. Often when shooters adjust a die to touch the shell holder, it is without a case being sized, and if you run a lubed, fired case up into the die to the top of the ram stroke, you will see a gap that wasn't there before. This will allow for additional adjustment. Years ago, I measured this gap while sizing .220 Swift FL brass, with a RCBS FL die and it was .006, this after having turned the empty die down till it touched the shell holder in my Rockchucker.

 

[John S]

I assume you have a good reason to be FL resizing?

For hunting and best accuracy, I would fire the brass once and neck size only.

I hate expander balls and love Lee Collet dies.

 

[abintx]

John ...

I assume you have a good reason to be FL resizing? For hunting and best accuracy, I would fire the brass once and neck size only.

FL sizing from day one maintains the original shape and concentricity of the cartridge and extends the life of the brass. Neck sizing only ... allows the body of the case to continue to expand to a point where eventually you have a tough time chambering it and a tough time extracting it. By that time the brass has taken on a new shape of it's own and time for retirement. Trying to FL size at this time ... to return it to it's original shape after only neck sizing ... is an exercise in futility.

 

[nhkuehl]

Expander ball

I do role a brush on the lube pad before inserting the brush in the case mouth before sizing. I don't lube the expander ball? Die is set up to contact shell holder. Is there a special type of lube to use on expander balls or case necks?
Thanks.

It takes a few passes to get enough lube on the expander ball so I usually put a light coat of lube (nothing special) on it before I start and then brush the inside of the case necks also. Having said that, like the others, I don't full length size or use an expander ball very often. I clean the di and expander ball between uses so that lube doesn't build up in the di and cause shoulder dents. The other posts covered shell holder thickness and the gap under pressure.

I've found about a 1% difference in case capacity between full length sized and necksized brass (SAAMI chambers) and that does influence your load. nhk

 

[kansasvet]

Boyd Allen was correct about the spring in a press when actually sizing a case. If you adjust your die against the shellholder as RCBS recommends, you will have a gap when you size a case.
You can address the problem two ways. Get a shorter shellholder by grinding the top of the shellholder, I use sandpaper on a flat surface and do it by hand, it usually doesn't take much. Or, adjust the die so the ram snaps over slightly on the bottom of the die.
When adjusting the FL die, size a case and try it in the rifle if it does not fit get a different case adjust the die down slightly and try again.
Bad experience is a good teacher, I used the same case over and over till it fit the rifle, proceeded to size all my cases with that adjustment and the rest of the cases would not chamber. My theory is that the spring of the press was less on the previously mostly sized case so that when I started sizing fired cases again they were springing the press more and were therefore longer.

 

[alinwa]

This reply is to the original post only. I'm making no comment on any of the replies.

jbordi,

A couple observations from my own experience.

#1, I NEVER just set the die to touch the shellholder. Instead I put a stack of Skips Die shims under the lockring, a stack totaling around .008-.010 and then screw down to gently touch the shellholder. Now reset the shims to add maybe .003 to the stack which should result in a GAP of around .003 at the shellholder....... now you've set up to play within a range, + and - where you need to be. Use this range to establish your use.

#2, I assume nothing re the length, taper nor size of the die as related to my chamber.... except that they DO NOT MATCH. My presumption is that they do not match but sometimes after measuring up I'm pleasantly surprised when they do.

#3, I feel it's important to have a way to actually measure the affected areas.

#4, I feel it's absolutely imperative that you write everything down. What I do is sketch a couple-three cases in my notebook, and a chamber drawing. I said SKETCH.... I use lined notebook paper and it's pretty easy to sketch a case by starting 4 lines wide and "necking down" to 2 lines at the neck.

I write down fired case dimensions of once-fired, fired until tight as well as resized dimensions......

I guesstimate my chamber to be same LENGTH as tight fired case and .0005 larger in diameter. This has proven to be accurate enough to order reamers/dies from.


One thing you'll notice, and this may be pertinent to your situation, is that while adjusting your die, as you get close to touching the shoulder the cases will GROW in length at the shoulder. This is because you've squeezed the case but not contained the shoulder with the die. It MUST bulge forward. Squeeze a balloon to see it bulge out of your grip. You must gently creep the die downward until it resets the bulged shoulder. You do this by shuffling he Skips Die Shims.

A properly set die will be set to just "bump" or reset the shoulder, LESS THAN .001.... Anything more than .001 of shoulder setback and you're risking head separation.


opinionsby





al

 

[Jbordi]

Thanks everyone!


Al,

This is exactly what I think may be happening. I will try this. Thanks!

One thing you'll notice, and this may be pertinent to your situation, is that while adjusting your die, as you get close to touching the shoulder the cases will GROW in length at the shoulder. This is because you've squeezed the case but not contained the shoulder with the die. It MUST bulge forward. Squeeze a balloon to see it bulge out of your grip. You must gently creep the die downward until it resets the bulged shoulder. You do this by shuffling he Skips Die Shims.

 

[abintx]

If you don't have shims, Bud Mundy has them as a [7/8-14] set for $7 plus $1 for shipping. You can reach Bud at 314-805-1313. I just bought some.