When to neck turn 6BRA?

[samb300]

Hi all,

New to the forum, but not a new shooter. I've been shooting 6.5x47L the past few years and plan to try a 6BRA next year. I have a 21st Century turning lathe and plan to neck turn to a minimum clean up (more for consistency - I have no plan to use a tight neck reamer), but I'm wondering if it's ok to neck turn the virgin 6BR cases before they are fireformed into 6BRA? If so, then I'm good to go, but I wasn't sure if the change in shoulder angle after fire forming means it's better to neck turn afterwards...

Thanks,

Sam

 

[newbieshooter]

Not sure if it's better, but I turn the necks before they are fireformed. I also turn a wee bit into the shoulder to account for the change in shoulder angle. Seems to work for me but YMMV.

Here is an example of a 'wee bit':

 

[Jeff A]

I turn mine before first firing which is Fire-forming. I have the PMA tool with a cutter for a 30 degree shoulder and turn so that the cutter just "kisses" the shoulder, nothing more. Many of my cases don't even show marks on the shoulder all of the way around.

 

[R.Morehouse]

I shoot a 268 neck and do it comin' out of the box & the primer pockets after FF.....

Regards
Rick

 

[johara1]

You had better think, it head spaces off the shoulder neck area the first time to hold the case back against the bolt face and make a perfect case. I shoot .266 and .268 necks and they have to be turned to fire fire formed, so I turn to the shoulder but I don't touch it. After I fire form I turn it again with a 40 degree cutter into the shoulder a little to help with the donuts and I ream the the inside of the neck..... jim

 

[johara1]

Not sure if it's better, but I turn the necks before they are fireformed. I also turn a wee bit into the shoulder to account for the change in shoulder angle. Seems to work for me but YMMV.

Here is an example of a 'wee bit':

View attachment 1072161

You went too far for the first time..... jim

 

[samb300]

So, you have to size that fireformed ID in order for it your fit the turning mandrel snugly. You can't size it with a standard bushing sizing die because the case neck at the shoulder junction will not be sized small enough due to the bushing bevel and/or the effective length of the bushing.

The only way I can see you accomplishing this is with a custom full length/ non-bushing sizing die.
Did you make your own dedicated full length sizing die that creates an ID .001 larger than the OD of your turning mandrel and sizes the ENTIRE neck length? Or is the case neck over-sized with your custom FL die, and then you expand before turning?

Jack

This is a great question. I was thinking about having a custom FL die made, but that turning process would be a bit of chicken or the egg. Get dies made off of once-fired brass, but you wouldn't be able to do the second turning until after the dies were made and you sized the brass, then expanded the necks with a mandrel.

 

[johara1]

So, you have to size that fireformed ID in order for it your fit the turning mandrel snugly. You can't size it with a standard bushing sizing die because the case neck at the shoulder junction will not be sized small enough due to the bushing bevel and/or the effective length of the bushing.

The only way I can see you accomplishing this is with a custom full length/ non-bushing sizing die.
Did you make your own dedicated full length sizing die that creates an ID .001 larger than the OD of your turning mandrel and sizes the ENTIRE neck length? Or is the case neck over-sized with your custom FL die, and then you expand before turning?

Jack

Jack, I run the mandrel in there for the neck turner it has to expand the case neck out of the box, if it didn't I have a fl. die I bored the body out so the only thing it does is size the neck. I use it for after they are turned when the fired neck is too large for the mandrel .... It works great if you dent one, size it down and run the mandrel in ....BTW I have no less than three different brands of neck turners and every mandrel will expand the neck right out of the box.... jim

 

[johara1]

This is a great question. I was thinking about having a custom FL die made, but that turning process would be a bit of chicken or the egg. Get dies made off of once-fired brass, but you wouldn't be able to do the second turning until after the dies were made and you sized the brass, then expanded the necks with a mandrel.

I turn three times, you don't need a custom die.... Forster FL non bushing die works great. all I use the die for is neck turning and use a Harrell's bushing die for loading...... jim

 

[samb300]

If one were to cut too far into the shoulder on initial neck turning, could that be overcome by loading the bullets with a jam into the lands for fire forming?

 

[newbieshooter]

You went too far for the first time..... jim

I still get a crush fit when I close the bolt on these turned cases for FF'ing. True, I no longer get the original .004 crush fit, but if I had to quantify - maybe a .003 crush fit? Correct me if I'm wrong here - but I figured if I still have a crush fit, the cases will FF correctly?

 

[johara1]

How are you measuring it ? jim

 

[bugman]

If one were to cut too far into the shoulder on initial neck turning, could that be overcome by loading the bullets with a jam into the lands for fire forming?

definitely...make sure you have enough neck tension to handle about .015 jam. Some people use the suspenders and belt approach and use crush and jam at the same time

Jack

 

[johara1]

This is confusing. I use forster full length dies whenever I need to re-turn 6BR, Dasher, PPC and 30 BR brass. These dies are cheap and effective. I was not aware that forster offered a 6BRA full length die. I tried using my 6BR die, but the 40 degree shoulder was boogered before I could reach the BRA neck. Please explain.

Jack, read a little closer I bored it and it is shorter and the shoulder is 90 degrees will size anything in 6mm...... jim

 

[johara1]

definitely...make sure you have enough neck tension to handle about .015 jam. Some people use the suspenders and belt approach and use crush and jam at the same time

Jack

Why?? the case holds it back you don't need any reason to seat them long..... jim

 

[Alexander-M]

Did I mess up?

I am just getting started on my 6mmBRA, and trying two approaches to forming the brass.
(1) I sent a batch of cases to DJ’s for hyrdro forming, which I am expecting back any moment now.
(2) I will also by fire-forming some myself, and then decide which method I like best. I have the 30° and 40° cutters to be able to turn either the 6MMBR cases, or the BRA cases.

For the ones I will be fire forming, I already turned the necks of a handful to fit the Ø0.268” chamber. I turned the necks to Ø0.2635, leaving the wall about 0.0112.

Problem?
I set the 21st Century lathe to turn into the shoulder about 0.06”, as I do when turning the 6.5-284 brass for the .284-Win.

After reading this thread, I am afraid I may have cut too far into the shoulder, and won’t do it again.
Would there be any problems in shooting (fire forming) the cases I already turned?


Thanks!
Alex

 

[bugman]

Why?? the case holds it back you don't need any reason to seat them long..... jim

Jim

Read a little closer. samb300 wrote that he turned too far down onto the shoulder, and lost the crush fit

 

[samb300]

Jim

Read a little closer. samb300 wrote that he turned too far down onto the shoulder, and lost the crush fit

I haven't turned any yet, I've been approaching this with some caution since it's my first foray into anything remotely wildcat. Better to ask now and neck turn later!

 

[samb300]

Did I mess up?

I am just getting started on my 6mmBRA, and trying two approaches to forming the brass.
(1) I sent a batch of cases to DJ’s for hyrdro forming, which I am expecting back any moment now.
(2) I will also by fire-forming some myself, and then decide which method I like best. I have the 30° and 40° cutters to be able to turn either the 6MMBR cases, or the BRA cases.

For the ones I will be fire forming, I already turned the necks of a handful to fit the Ø0.268” chamber. I turned the necks to Ø0.2635, leaving the wall about 0.0112.

Problem?
I set the 21st Century lathe to turn into the shoulder about 0.06”, as I do when turning the 6.5-284 brass for the .284-Win.

After reading this thread, I am afraid I may have cut too far into the shoulder, and won’t do it again.
Would there be any problems in shooting (fire forming) the cases I already turned?

View attachment 1072226
Thanks!
Alex

I thought the main benefit of 6BRA vs. the Dasher (or similar) was easy fireforming, i.e. no need for hydroforming. Since I don't have a reamer or barrel in hand yet, I'm curious as to whether or not you drastically affect the crush fit for fireforming with your neck turning depth into the shoulder. I want to prep brass over the winter as I likely won't have a new barrel chambered until spring, but I don't want to screw up all of it either.

 

[johara1]

I haven't turned any yet, I've been approaching this with some caution since it's my first foray into anything remotely wildcat. Better to ask now and neck turn later!

All you need to turn is enough you are below the pressure ring on the bullet don't hit the shoulder the first time. Load them and clean the chamber with non- chlorinated brake cleaner. then the cases on the loaded rounds and you will get a blow length of 1.550+. Take your time and do it right, I do 5 and let the barrel cool and clean the chamber again..... The volume will be very uniform..... jim