When to neck turn 6BRA?

[johara1]

Jim

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

If you want to salvage them make a false shoulder or throw them away... a bullet will not hold them back uniformly plus use a soft primer, I use feds for fireforming. jim

 

[foxguy]

In regards to Fire Forming the 6MM BR to 6MM BRA.

I turned my necks to .011, so I had a Bullet - .243, + 011, + .011 = .265 (for a .268 chamber)


When I tried to check the neck turned brass in the Rifles chamber I learned I couldn't close the bolt.

So at this point I decided I needed to bump the 30 degree shoulder back a little in order to be able to close the bolt on the 6MM BR factory brass. I bumped the shoulder back just enough to close the bolt without the crush fit feel. (I had read crush fits can gall the lugs and action recesses, I didn't want that).

I loaded them up, a 95 gr bullet +.005 into the lands and shot them. It seemed to work.

As I'm still learning about the 6MM BRA, and being new to fireforming, If there's an easier way- I'm all for it.

 

[steve123]

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

If you wanted to go through the effort and spend the money, you could expand the necks to 25 cal with a expanderon and reset a false shoulder by necking back down to 6mm.

Fox, if concerned about galling lugs all you need to do is grease the lugs, and all that's needed is a slight crush fit on the shoulder for fireforming, just go by feel of downward pressure of the bolt, let common sense guide you.

 

[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!

If you need more help PM me and I will be glad to tell you step by step. I like the 6br imp. because how easy it is to make great cases, the Dasher was a lot of work to make them..... jim

 

[JohnMill]

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

Hey,
I too turned b4 FF and had about 1/2 the ledge as your wee bit. I was still uncomfortable with it as I thought it provided a shear point. I used a diamond file ( really just that diamond sandpaper on a handle)to polish the ledge out. No problem. Just time. Was it necessary? Don't know but I have a feeling that 72000psi can make brass do some awful stuff.

 

[JFrank]

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

How well did these fire form ? Just curious as I don’t turn necks very often.

 

[BartsBullets]

How well did these fire form ? Just curious as I don’t turn necks very often.

4 year old post. You maybe waiting a while for an answer.

 

[JFrank]

4 year old post. You maybe waiting a while for an answer.

Yeah I knew it was older, but still curious how they turned out- hopefully Alex is till around.