FL Die barely sizes neck, can crimp suffice?

[PinesAndProjectiles]

I’ve been messing with the 6x6.8SPC. The rifle is a home built AR with a BHW barrel from Rich’s Precision Guns.

I’ve noticed on this new batch of brass, after FL sizing, I’ve only got about .001” of neck tension.

I am NOT using an expander ball or removing primers with the FL die.

I purchased a seating/crimp die.

If I am able to crimp, then the neck tension will not matter as much, correct?

I realize that seating a .243 bullet in a neck that’s .243 or larger wouldn’t keep the bullet straight in the neck.

But some neck tension and a crimp would suffice, correct?

 

[ShtrRdy]

What kind of resizing die are you using? Does it use a neck bushing?

 

[918v]

Seat the bullet and see if it feels good when seating. You should know what a bullet should feel like when seating based on other rounds.

 

[PinesAndProjectiles]

The die is made by CH4D. It does not use a bushing.

There seems to be very little resistance when seating a bullet.

 

[918v]

Is there bullet setback when cycling the weapon?

 

[918v]

If I am able to crimp, then the neck tension will not matter as much, correct?

I have never seen crimp improve bullet hold other than a roll crimp on a revolver cartridge.

I think your die is meant to be used with necked down brass, and you’ll need a different die for new brass.

 

[supercorndogs]

The problem as I see it with crimping vs interference fit is the fact that you have have to squeeze the bullet to when you crimp. I had to get a smaller bushing for my 20 practical because of the same problem. I do use an expander but I could barely feel it drag on the way out. It set bullets back into the case feeding. I wouldn't trust it. I would get a diffrent die or thicker brass.

 

[Rocketvapor]

Neck O.D. after sizing?
Neck O.D. after seating?

 

[Mike Casselton]

Is your sizing die a 6.8 or 6-6.8?

Can't tell from what you wrote.

 

[PinesAndProjectiles]

The CH4D die set is, as far as I know, intended to neck down 6.8 brass to a ready to load condition in one stroke of the press handle. It is specifically a 6x6.8 die set.

As for bullet setback, I’m not sure. I’ll have to get back to you.

A sized case is .267. A loaded round is .2675-.268. So only a thou of neck tension.

 

[Mike Casselton]

Just to clarify a bit more.

You say your set is for forming down from 6.8 to 6mm neck.

Is one of your dies marked FL or Full Length?

Sometimes, forming die sets aren't designed to completely size brass to a loadable condition.
Some sets require an actual FL die to complete the process.



In actuality, going from 6.8 to 6mm shouldn't require anything other than a straight neck down in the FL die.

An intermediate step would be like using your seater die for the first pass. Gets it close, but not all the way down.



Does any of that help or make sense?

 

[Mike Casselton]

An example would be 221 Fireball to 17 Mach IV.

A form die set first pass takes the neck to 20 caliber.
2nd pass to .18 and final pass is with the FL die.

3 steps total.



A simple way around the form die set is to polish the seater die with the guts removed.
A pass through the die takes the neck to .18 caliber. It essentially bypasses the 1st step die.

Then through the FL die.

2 steps to a finished piece of brass.



Necking down less than 1mm can usually be done in a single pass with the FL die. No forming die needed.

Think 6.5 Grendel to 6 ARC, or 6.5 CM to 25 CM or 6 CM. Single pass and you're done.

 

[PinesAndProjectiles]

Just to clarify a bit more.

You say your set is for forming down from 6.8 to 6mm neck.

Is one of your dies marked FL or Full Length?

Sometimes, forming die sets aren't designed to completely size brass to a loadable condition.
Some sets require an actual FL die to complete the process.



In actuality, going from 6.8 to 6mm shouldn't require anything other than a straight neck down in the FL die.

An intermediate step would be like using your seater die for the first pass. Gets it close, but not all the way down.



Does any of that help or make sense?

That does make sense. The die is marked “FL” and everything I’ve read about it says that it sizes 6.8 brass to 6x6.8 without any other steps.

 

[Mike Casselton]

Your new brass must have pretty thin necks.
That is most likely the answer.
Do you have any other brass to compare it against?

 

[PinesAndProjectiles]

I do but I’m headed out of town so comparing them will have to wait.

Thanks for the help, Mike! Much appreciated!

 

[Rocketvapor]

Have a nice trip.

From your loaded measurements 0.2675" - 0.268" your neck thickness is 0.01225" to 0.01250"
I have some Hornady 6mm Hagar brass that measures 0.2675" loaded,
and some Winchester 243 Win brass that measures 0.2705" loaded.
That's a neck thickness range of 0.01225" to 0.01375".

A die that would size the 6mm Hagar brass for 2 thou "tension" would give 5 thou to the 243 Win,
The reverse of that would be 2 thou "tension" on the .243 Win brass and a easy slip fit on the Hornady brass.
One size does NOT fit all.

I think your brass is thin necked, like my 6mm Hagar brass.
0.272" is the SAMMI MAX cartridge for 6X45,
and 0.273" the MAX cartridge for 6GT,
and 0.274" the MAX cartridge for 6 ARC,
and 0.276" MAX for the 6mm Rem, 6mm CM and 243 Rem,
and
0.269" MAX for the 24 Nosler.

 

[PinesAndProjectiles]

Have a nice trip.

From your loaded measurements 0.2675" - 0.268" your neck thickness is 0.01225" to 0.01250"
I have some Hornady 6mm Hagar brass that measures 0.2675" loaded,
and some Winchester 243 Win brass that measures 0.2705" loaded.
That's a neck thickness range of 0.01225" to 0.01375".

A die that would size the 6mm Hagar brass for 2 thou "tension" would give 5 thou to the 243 Win,
The reverse of that would be 2 thou "tension" on the .243 Win brass and a easy slip fit on the Hornady brass.
One size does NOT fit all.

I think your brass is thin necked, like my 6mm Hagar brass.
0.272" is the SAMMI MAX cartridge for 6X45,
and 0.273" the MAX cartridge for 6GT,
and 0.274" the MAX cartridge for 6 ARC,
and 0.276" MAX for the 6mm Rem, 6mm CM and 243 Rem,
and
0.269" MAX for the 24 Nosler.

I understand this portion of it, but being it’s already a specialty die, can I crimp as a means of holding the bullet in the neck of the case?