Neck turning before fireforming- how far?

[Drolds72]

new 6bra with a 268 neck. I got the diameter set for a 265 loaded round, but how far down should I go? This far enough, or just a bit more to actual junction?

 

[dmoran]

A bit more.... into the actual junction.

 

[Drolds72]

Better?

 

[dmoran]

Yep... that's better..... even a hair more (if it was me)

 

[zipollini]

First make sure that your cutter has the right angle to start cutting into the shoulder area. I use the 21st Century neck turning lathe and a 30 deg. cutter to match the 30 shoulder on my 6XC brass. Cutting into the shoulder area will reduce or eliminate donuts forming.

http://www.xxicsi.com/neck-turning-lathe-complete.html

 

[Drolds72]

First make sure that your cutter has the right angle to start cutting into the shoulder area. I use the 21st Century neck turning lathe and a 30 deg. cutter to match the 30 shoulder on my 6XC brass. Cutting into the shoulder area will reduce or eliminate donuts forming.

http://www.xxicsi.com/neck-turning-lathe-complete.html

Exactly what I am using. 21st century with 30 deg cutter. Then, I am bumping .0015 so I am getting just the slightest crush feel on bolt close with an empty piece of brass. Guess next step is to seat right at the lands and start fire forming.

 

[Drolds72]

Ok. Feeling pretty good about this one!

 

[dmoran]

I like it......

 

[zipollini]

Yeah - Turn into the shoulder until it looks like the picture of Dmoran's. No need to seat a bullet to fire form. Just use the COW (Cream of wheat) method.

 

[David Christian]

@dmoran, I have been curious about this. If you turn before fireforming, do you then need to re-turn your brass after the 3rd or 4th firing as the shoulder has moved into the neck? Is there any logic in fireforming the brass before turning to avoid or dramtically delay a second turning? Thanks

 

[Drolds72]

@dmoran, I have been curious about this. If you turn before fireforming, do you then need to re-turn your brass after the 3rd or 4th firing as the shoulder has moved into the neck? Is there any logic in fireforming the brass before turning to avoid or dramtically delay a second turning? Thanks

Good question, I have not thought that far ahead, but I had to turn to be able to chamber the tight neck...

 

[dmoran]

@David Christian
Typically, by cutting the necks first and to the shoulder junction, eliminates donut/taper issues, because the junction will get fire-formed into the shoulder portion (more so with Improved wildcats, example picture below) of the case. But at the same time, brass does flow forward in all cartridges from repeated cycles, and further clean up passes may be warranted (dependent on the cartridge, chamber clearances, and amount of growth). Myself always perform repeated clean up passes on all cartridges that I neck turn, as they get cycled and the brass flows forward, and see the gains in neck tension consistency by doing so.


An Improved cartridge example (6Dasher)

 

[AJC]

@David Christian
Typically, by cutting the necks first and to the shoulder junction, eliminates donut/taper issues, because the junction will get fire-formed into the shoulder portion (more so with Improved wildcats, example picture below) of the case. But at the same time, brass does flow forward in all cartridges from repeated cycles, and further clean up passes may be warranted (dependent on the cartridge, chamber clearances, and amount of growth). Myself always perform repeated clean up passes on all cartridges that I neck turn, as they get cycled and the brass flows forward, and see the gains in neck tension consistency by doing so.


An Improved cartridge example (6Dasher)
View attachment 1083088

So in the case of pushing the shoulder forward you would be making the neck section thinner right. I see how you could eliminate ever getting donuts because the shoulder is now neck thickness and the case must be garbage before you ever get that much growth/forward flow.

 

[jobhopper66]

Donovan is the man to listen to. His advice is always spot on!
Ray

 

[dmoran]

@AJC
That's the perception, and my own experience. But I cant speak to all cartridges and/or scenario's.

 

[AJC]

@AJC
That's the perception, and my own experience. But I cant speak to all cartridges and/or scenario's.

I dont know enough about case design to know if that is a safe way to operate, but empirical evidence seems to say it prevents a problem and people are not blowing up guns so it must be OK.

 

[Petros284]

@David Christian
Typically, by cutting the necks first and to the shoulder junction, eliminates donut/taper issues, because the junction will get fire-formed into the shoulder portion (more so with Improved wildcats, example picture below) of the case. But at the same time, brass does flow forward in all cartridges from repeated cycles, and further clean up passes may be warranted (dependent on the cartridge, chamber clearances, and amount of growth). Myself always perform repeated clean up passes on all cartridges that I neck turn, as they get cycled and the brass flows forward, and see the gains in neck tension consistency by doing so.


An Improved cartridge example (6Dasher)
View attachment 1083088

As usual Donavan is spot on! I perform a clean up turn of my Dasher brass after firing as well.

Pete Petros
21st Century Shooting

 

[foxguy]

As usual Donavan is spot on! I perform a clean up turn of my Dasher brass after firing as well.

Pete Petros
21st Century Shooting

If you are performing a clean up turn after each firing, does the clean up neck turning effect the number of firings are you getting on a piece of brass?


I'm shooting a 6MM BRA and I'm new to turning necks. (6MM BRA .268 neck - Laupa 6MM BR brass turning to .011.)

Thanks

 

[LCazador]

@David Christian
Typically, by cutting the necks first and to the shoulder junction, eliminates donut/taper issues, because the junction will get fire-formed into the shoulder portion (more so with Improved wildcats, example picture below) of the case. But at the same time, brass does flow forward in all cartridges from repeated cycles, and further clean up passes may be warranted (dependent on the cartridge, chamber clearances, and amount of growth). Myself always perform repeated clean up passes on all cartridges that I neck turn, as they get cycled and the brass flows forward, and see the gains in neck tension consistency by doing so.


An Improved cartridge example (6Dasher)
View attachment 1083088

My personal experience having done the 6 Shehane, 6BR long, 6BRA, 6 Dasher, Whew! If you don't cut into the shoulder enough your brass is garbage! I'll agree with everything "dmoran" say's in doing fireform!

 

[Petros284]

If you are performing a clean up turn after each firing, does the clean up neck turning effect the number of firings are you getting on a piece of brass?


I'm shooting a 6MM BRA and I'm new to turning necks. (6MM BRA .268 neck - Laupa 6MM BR brass turning to .011.)

Thanks

I have seen no difference at all since the clean up cut is removing minimal material. As long as you anneal your brass ( I do so every other firing) and run your loads at a moderate node your brass can last many firings. My Lapua Dasher brass has lasted me at least a dozen firings if not more.