Neck Straitening Before Turning

[Silo1616]

There was a discussion here (in the last year) regarding case neck concentricity and/or straitening after expanding and before turning. Part of it delt with techniques during expansion and another about straitening methods.

I’m turning brass for next season and seem to be getting an unusually uneven cut when I touch the shoulder.

I can’t seem to find the thread using search, does anybody remember the thread name? Have it bookmarked?

 

[Straightshooter1]

There was a discussion here (in the last year) regarding case neck concentricity and/or straitening after expanding and before turning. Part of it delt with techniques during expansion and another about straitening methods.

I’m turning brass for next season and seem to be getting an unusually uneven cut when I touch the shoulder.

I can’t seem to find the thread using search, does anybody remember the thread name? Have it bookmarked?

Are you fire forming the brass first? Fire forming tends to straighten things out nicely. The other issue involved is how consistent the thickness of the brass is. If you're using brass that has substantial thickness variation, that can show up as an uneven cut when touching the shoulder when turning them.

 

[Webster]

There was a discussion here (in the last year) regarding case neck concentricity and/or straitening after expanding and before turning. Part of it delt with techniques during expansion and another about straitening methods.

I’m turning brass for next season and seem to be getting an unusually uneven cut when I touch the shoulder.

I can’t seem to find the thread using search, does anybody remember the thread name? Have it bookmarked?

Like above FF first. As far as case thickness uniformity think of how the brass is formed by extruding like spaghetti in at least four dies to make a case. They are not made by machining. They start out as a disc like a coin. I think the only machined part is the rim diameter, the extractor grove and over all length. You should barely touch the shoulder.

Nice article on how brass is extruded. I would expect uneven thickness on a case.

You are being redirected...

 

[Silo1616]

Are you fire forming the brass first? Fire forming tends to straighten things out nicely. The other issue involved is how consistent the thickness of the brass is. If you're using brass that has substantial thickness variation, that can show up as an uneven cut when touching the shoulder when turning them.

Fire forming after turning (wont chamber otherwise). Lapua brass.

 

[Straightshooter1]

Fire forming after turning (wont chamber otherwise). Lapua brass.

Then I'd only turn the necks enough that they'll chamber without doing anything on the shoulder. Once they fit, I'd fire form them and turn them to my preference.

 

[TTE]

Fire forming after turning (wont chamber otherwise). Lapua brass.

as others have mentioned .... turn until they j u s t fit, then fire form without a bullet

 

[AlNyhus]

I’m turning brass for next season and seem to be getting an unusually uneven cut when I touch the shoulder.

Are you full length sizing (including all of the neck length) prior to neck turning?

 

[misser]

I have turned necks . to straighten them,?? ya have done that to, after the bullet in seated ,not abit surprised you find you are taking more off one side than the other

 

[rwj]

as others have mentioned .... turn until they j u s t fit, then fire form without a bullet

Curious why recommend without a bullet?

 

[JMayo]

If you have the die run it after expanding. If you don't have the die about the only thing you can do it get your 2-3 by trimming into the shoulder a small amount. And wait for the die.
I use a harrels bushing die, no mandrel

Any I've ever had done by the guys that do brass had a portion that seemed cut into, like a 25% swath area that was cutting into the hump.

(Ps, bullet makes it bigger around)

 

[Silo1616]

Are you full length sizing (including all of the neck length) prior to neck turning?

No, turning after expanding only. I'll try full length sizing then re-expanding and see if that helps. Thanks

 

[rwj]

(Ps, bullet makes it bigger around)

Yes it does… but lack thereof decreases pressure and the likelihood of the case completely expanding to conform with the chamber.

 

[TTE]

Curious why recommend without a bullet?

OP said he had to trim the necks or the brass would not fit.
If he trims so the brass has a small amount of interference, that will hold the brass against the bolt face. FF without a bullet would not create the need for more trimming (for bullet release).

True, after FF this way, he would have to trim the necks again at some point. However it would help with straightening the necks to his chamber also.

Annealing the cases may also help.

 

[jackieschmidt]

The way I make my 30BR cases insures that they are straight before neck turning.
I first fire a full loaded Lapua 6BR case in a special 6 mm barrel that has a .330 neck in it.

What comes out is a perfectly formed no neck turned 30BR case.
I then neck turn them.

 

[bozo699]

OP said he had to trim the necks or the brass would not fit.
If he trims so the brass has a small amount of interference, that will hold the brass against the bolt face. FF without a bullet would not create the need for more trimming (for bullet release).

True, after FF this way, he would have to trim the necks again at some point. However it would help with straightening the necks to his chamber also.

Annealing the cases may also help.

^^^^^^
Wayne

 

[Silo1616]

No, turning after expanding only. I'll try full length sizing then re-expanding and see if that helps. Thanks

Update... Full length sizing and then re-expanding before turning seems to have cured the problem.

Thanks to all for your input.