Fireforming in 6BR?

[marchx]

I shot recently 2 short range benchrest matches using virgin Lapua brass. One of the members here said that he neck sizes only his brass up to 3rd firing. If I am not mistaken he gets different pressure during 2nd and 3rd firing since the brass still expands. Isn't FL sizing (in a no turn chamber) every single time a better way to achieve consistency?

 

[Bill Norris]

According to a video that Erik Cortina has posted it is best to F/L size each time as he points out exactly what you are asking here with a good drawing.

 

[marchx]

According to a video that Erik Cortina has posted it is best to F/L size each time as he points out exactly what you are asking here with a good drawing.

@Bill Norris I saw Erik's video a year ago but in another thread another member referred to his "neck sizing only up to 3rd firing" approach.

 

[rwj]

If you’re planning on buying a custom resizing die, most suppliers want cases that have been fired multiple times without being resized so that the body closely represents the chamber dimensions.

 

[Dusty Stevens]

You can still fl size and not bump the shoulders. Dont let the body get out of hand by neck sizing only- sometimes it wont go back

 

[bozo699]

You can still fl size and not bump the shoulders. Dont let the body get out of hand by neck sizing only- sometimes it wont go back

^^^^^^^^^
Wayne

 

[mikecr]

Is it your competitive plan to shoot matches with virgin brass?
Do you plan to have a fitted die made, or to size with what you have?

 

[marchx]

If you’re planning on buying a custom resizing die, most suppliers want cases that have been fired multiple times without being resized so that the body closely represents the chamber dimensions.

I am not planning to do that. what would the accuracy gain in doing that? Of course, it will help with working my brass less, so it may survive longer, but apart from that?

 

[Dusty Stevens]

I am not planning to do that. what would the accuracy gain in doing that? Of course, it will help with working my brass less, so it may survive longer, but apart from that?

Good dies make your gun run better and faster so less disturbance in the bag= way better accuracy

 

[marchx]

Is it your competitive plan to shoot matches with virgin brass?
Do you plan to have a fitted die made, or to size with what you have?

To some extent it is. I won last 2 matches shooting virgin brass. Brass up to 3rd firing keeps well consistent neck tension.

 

[marchx]

Good dies make your gun run better and faster so less disturbance in the bag= way better accuracy

Pls help me understand your rationale. We have (a) a standard FL die (a Redding or a Whidden- a quality die). We get the same dimensions after FL sizing our brass. So brass keeps the same shoulder bump etc. (b) We have also a custom sizing die- we also get consistent dimensions out of it, the only difference being the body and shoulders are worked to the minimum. Why will I get better accuracy from a custom die?

 

[bozo699]

To some extent it is. I won last 2 matches shooting virgin brass. Brass up to 3rd firing keeps well consistent neck tension.

That’s why they make annealing machines
Wayne

 

[fkimble@charter.net]

'Why will I get better accuracy from a custom die?"

He's not talking better accuracy per se, he's talking better gun handling, more consistant bag riding. The bolt opens and closes smoother without needing to be realigned after each shot"

Frank

 

[marchx]

Virgin brass has plenty of bullet hold, your set up seems to favor that, annealing softens brass so if your set up likes light hold you may see improvement or decline.

I expand the neck of my virgin brass and trimm it to desired length.

 

[marchx]

'Why will I get better accuracy from a custom die?"

He's not talking better accuracy per se, he's talking better gun handling, more consistant bag riding. The bolt opens and closes smoother without needing to be realigned after each shot"

Frank

The same happens if you FL size your brass. You are right., but I m confused re custom dies. I am wondering why Erik Cortina is running standard Redding die instead of a custom one (he publicly admitted to that).

 

[marchx]

That’s why they make annealing machines
Wayne

You are right. I made tests with annealed brass (5x times fired) and non-annealed brass once fired. Consistency in neck tension was better in the latter group.

 

[bozo699]

You are right. I made tests with annealed brass (5x times fired) and non-annealed brass once fired. Consistency in neck tension was better in the latter group.

My findings have been the opposite,…. May more consistent annealed after each firing .
Wayne

 

[LCazador]

@Bill Norris I saw Erik's video a year ago but in another thread another member referred to his "neck sizing only up to 3rd firing" approach.

I full length size with .002" but I recently went with .003" bump. More bump appears to achieve more consistency!! I've been doing this with PPC and 6BR for 40+ years but what works in one caliber isn't going to work for all guns and calibers. Neck sizing introduces too many variables for me.

 

[marchx]

I full length size with .002" but I recently went with .003" bump. More bump appears to achieve more consistency!! I've been doing this with PPC and 6BR for 40+ years but what works in one caliber isn't going to work for all guns and calibers. Neck sizing introduces too many variables for me.

Sir, I recently switched also to 0.003 bump. Thank you for your input.

 

[marchx]

Yes most guys expand/true the necks on virgin brass


What makes a good die in my shop is how it matches the chamber not who’s name is on the box.

I run a standard FL die and have no idea whatsoever how it matches my chamber.