Shoulder Bump 1 x fired brass ?

[Chubbs]

Hi Guys

I know fully formed brass does not occur until 3rd firing. but what do I set my die for. On my 1 x fired 6.5 Creedmoor brass using a hornady headspace gauge i get a range from 1.5310" - 1.5350". (The new cases were 1.5300")
Is it best to set for 1.5300" and let the shorter cases catch up. (My mistake should have said 1.533")

 

[JFrank]

I’m mainly looking at radial expansion until it doesn’t chamber freely.

 

[Longtrain]

That’s what a do with my Dasher, if needed. Almost always, the 1x brass will chamber without any problem, I’ll run them through the die just to do the neck, load them and shoot them. But, after a second firing I pretty much have uniform brass.

 

[AlNyhus]

On my 1 x fired 6.5 Creedmoor brass using a hornady headspace gauge i get a range from 1.5310" - 1.5350". (The new cases were 1.5300"). Is it best to set for 1.5300" and let the shorter cases catch up.

That's how I do it, for what it's worth. -Al

 

[Texas10]

I shoot a bolt gun in 6.5CM and prefer to neck size only or FL size but not bump the shoulder back until the brass has fully fireformed to the chamber. I verify this by chambering a fired brass and checking for stiffer than normal bolt drop. Once the brass has reached this point, I measure and record the dimensions of the brass and use that as a starting point for die setup. I make a spiral bound binder for each rifle that includes a drawing of the cartridge with critical dimension for quick reference, as well as all loading records for that action and barrel.

 

[Dusty Stevens]

Youve read it takes 3x to form the brass but theres no set number. Sometimes its more or less. Shoot it til you feel it getting stiff closing the bolt.

 

[SmokinJoe]

And only neck size in the meantime.

 

[Chubbs]

Hi Guys
Thanks for the replies. Trying to look for consistancy and have been neck sizing only up to this point. But thought I would give F/L sizing a go.

 

[David Christian]

I would try sizing the longest piece without bumping the shoulder and see if it chambers. If it does then there is no reason to bump them back .005.

 

[BoydAllen]

Measure your datum to head (with primer removed or reseated deep) of your once fired brass. Set your FL die to duplicate that measurement in a fired case. Try the case in the chamber (after removing the lube). It will probably go in just fine. The next time do the same thing, measure, set die to that measurement (which will probably be a little longer than the first one) , size, and check in chamber. Check all your sized brass and then try the longest one, they will vary.

Another way it to make a tight case from a once fired one: Decap, put scotch tape on head. Trim to open primer pocket and to bevel on outside of head with sharp Exacto knife. This should give you a case that is tight. Do not force the bolt closed. Measre it, and adjust your die from that measurement .001 at a time, wiping off lube and checking in chamber each time. Remember to reapply lube each time before sizing.

For me this is a slick way to do a precise way of setting a once fired case, when I am not loading for that round at the range. If I am loading at the range, I just size the end of the neck enough to hold the bullet and shoot one case until it gets snug and the shoulder to head dimension stabilizes, then I set the die to reduce that measurement by .001 , .002 for hunting ammo.

It is normal for new brass (including factory loaded ammo.) to be quite a bit short at the shoulder. Do not set your die to duplicate that measurement. Do not follow the instructions for setting your die that may have come with your die that say something like turn the die down till it touches the shell holder and then a quarter turn more. Do not do that.

 

[Chubbs]

Just noticed my mistake. I should have said set F/L die to size at 1.533".
But thanks for all the answers guys much appreciated.

 

[B23]

And only neck size in the meantime.

I agree but only if you're using a neck sizing only die.

Where people get themselves in trouble is when they think they can back a FL die off and neck size only with their FL die.

Nearly all of my stuff I neck size only but I only do so with the appropriate type of dies. Trying to neck size only with a FL die will result in you chasing your tail.

 

[Trevor60]

This is my cheat.
I take ONE piece of brass and shoot it 3 times using my preferred charge weight; neck sizing after each firing. Once i am comfortable the brass is fully expanded; I use Alex Wheeler's method of determining headspace.
I set my die based on the required resizing of the 3x case and F/L all other brass each time.
I get better side wall case management and i have a shoulder bump (stop) if any one case manages to reach my bump specs before the 3rd firing.

Cheers
Trevor

 

[Mikemci]

You can find your chamber datum too.
Pop the spent primer out of your 1x fired brass. Seat it back in the pocket, just enough to get it going straight. Load that brass and close the bolt. The bolt will push the brass to the front of the chamber and press the primer in. At that point you can measure with your headspace comparator, from the primer to the shoulder. Now you know how much further you new brass can grow, before you need to start setting the shoulder back.

 

[Uncle Ed]

With Redding competition shell holders they tell you to start with the plus .010 shell holder and work down with the +.008, +.006 until the bolt closes smoothly.

Meaning if you raise the die off the shell holder you can make the case longer than the chamber.

If you do not have the Redding competition shell holders you can use feeler gauges and work smaller until you get the proper shoulder bump.

Bottom line, you do not need to fire the case several times to make it fit the chamber. Just raise the die and squeeze the case shoulder forward and then push it back down by lowering the die for the proper fit.

 

[CA_Shooter]

With Redding competition shell holders they tell you to start with the plus .010 shell holder and work down with the +.008, +.006 until the bolt closes smoothly.

Meaning if you raise the die off the shell holder you can make the case longer than the chamber.

If you do not have the Redding competition shell holders you can use feeler gauges and work smaller until you get the proper shoulder bump.

Bottom line, you do not need to fire the case several times to make it fit the chamber. Just raise the die and squeeze the case shoulder forward and then push it back down by lowering the die for the proper fit.

Does this mean that sizing the case with the FL die will stretch it out without having to fire it?

 

[Uncle Ed]

Does this mean that sizing the case with the FL die will stretch it out without having to fire it?

A case that has not been fired has not expanded to fill the chamber. Meaning it does not become longer when full length resized.

A fired case is larger in diameter and the resizing die squeezes it smaller in diameter. When the case is squeezed and compressed the brass flows upward and moves the shoulder forward. Then during the last of the sizing operation, the shoulder begins to be pushed back down.

So as an example if the die is raised .020 off the shell holder the resized case could end up longer than the chamber. Meaning the case headspace would be longer than the chamber headspace because the case shoulder was squeezed forward.

Look closely at the image below again at the red, blue and green dotted lines, and shoulder movement.

 

[Richard Coody]

Hi Guys
Thanks for the replies. Trying to look for consistancy and have been neck sizing only up to this point. But thought I would give F/L sizing a go.

You can just neck size with a full length die

Just don't turn it down till it hits the shoulder

Back the die off, put a fired case in the shell holder and cycle the press. If you feel resistance stop and back the die off more. Once you cycle the press with no resistance then start turning the die down gradually, cycling the press and watching the neck. When you have the die set where most of the neck is sized but you are not touching the shoulder (when you get to the shoulder you will feel an increase in resistance) that is where you want to be until your brass is fully fireformed. It will become much faster with experience