FL Sizer flaring my rifle brass?

[Rmeju]

I've recently moved from neck to FL sizing for my first bolt rifle (7mm RM). I've been trying to take care of the brass. I used my LE Wilson adjustable gauge to adjust the die to get the shoulder pushed exactly 0.002" back from fire-formed, but for some reason my die seems to be flaring the mouth (see below). I've FL sized for three different service rifles and never had seen this, so I'm not sure what's going on.

Brass measured well under max before FL sizing, and just at or a hair under max after. Sizer is RCBS. Obviously, I could just trim the flare off, but I want to try to take care of the brass and avoid unnecessary trimming, plus I'd like to understand what's going on, and what to do to fix it.

Any help would be appreciated!

 

[macgrumpy]

Your expander ball is probably adjusted too low. Look at the image below and notice that if the ball is too low it will try to push the case mouth out until the mouth contacts the shoulder diameter of the die. You need to balance the location of the expander ball and the depth of the decapper pin. As you raise the ball the pin will also rise and you may not pop the primer out.

 

[Wildfire]

A lot not said.

There is too much not being said. I cannot see an expander ball flaring a case mouth. The only way that could happen would be if it was too high.
If that were the case it would not be sizing the case neck right. What dia. is the case neck? If way under sized, the expander ball is too high. The die should not be able to flare the case at all. The expander ball does go all the way through the case mouth. Or you have a very long de-capper pin.

When the case is pulled back out of the die it should smooth any flare out if there were one.
Shell holder right?
I would start by measuring some things.

 

[PCCUSNRET]

The only time I have experienced something like this is when making 25.06 from 30.06 brass. Once I trim the brass and resize the brass in RCBS FL die it goes away. Wish I could be more help.

 

[fguffey]

A lot not said.

There is too much not being said.

When the case is pulled back out of the die it should smooth any flare out if there were one.
Shell holder right?

No.

The neck mouth was folded when the neck went into the die when being sized. When the sizing plug was pulled through the neck the fold became a flare. When the reloader chamfers and bevels the neck it will be like it never happened.

Shell Holder?

F. Guffey

 

[Wildfire]

OK

I have never seen a case with a flared case mouth after leaving a sizing die.
The expander ball cannot flare a case. It sizes the case neck inside. The die sizes the outside of the case and neck.
Guess this is a new one me.
I always size, then trim and clean or debur. I have never seen this happen with any of my rifle dies in over 35 years of loading.

 

[rcmodel]

I think what Mr. Guffy was saying is that there was a remnant rolled crimp in the case mouth folded inward.

Sizing didn't iron it out because it didn't touch the die.
In fact, it probably got more pronounced as the neck sized down.

But as the neck became smaller after sizing, the expander pushed the mouth crimp out coming back out.

Chamfering and deburring before sizing will likely cure it.

rc

 

[Wildfire]

Sounds more like it.

I load very little new brass.
I use a lathe to prep most of it. It is faster and easy.
The last batch of .300 win mag brass was new. But, it was debured before sizing and then trimmed.
I know we all do things different.
I just could not see how a die would create this flare issue.
I also know some mix and match tools to get different results. Nothing is perfect these days.

 

[243winxb]

Think of a die, with a donut, where the neck connects to the base of the shoulder. Defective die. I run a fired 308 case into my Redding 243 type S FL bushing die, without a bushing. No Expander was used.. The result were the same, a flared case mouth. Thats my guess.

 

[fguffey]

That’s my guess.

Think of a die, with a donut, where the neck connects to the base of the shoulder.

If that was your guess you would be wrong. Try to think of it this way; the mouth of the case is thin and is the first part of the case that gets sized. When the diameter of the neck is reduced the thin edge of the case mouth turns in when the neck starts to be sized. When the ram is lowered the size plug expands the neck and creates a flare at the case mouth.

This can not be fixed because reloader refuses to trim first then size, and then there is the trim to length. There are reloaders that do not have a clue and never experience this problem because they use Lee cullet dies and or RCBS ‘X’ dies.

F. Guffey

 

[Wildfire]

This makes more sense. I always trim and clean case mouths and then size and trim to where I want them. Likely why I never saw this happen.

 

[farmerboy78]

The only time I have seen this is when I reform .308 win brass to 6.5 Creedmoor. Once ran through the Creedmoor die without the spindle, the neck is too long and flared out. After I trimmed to length, I haven't had any problems since. I'd remeasure the case for an oal.

 

[Rmeju]

I trimmed chamfered and deburred prior to sizing, per the above suggestion. That definitely made the flare less pronounced, but it is still occurring.

I'll see what RCBS has to say and report back.