resized brass variations of +/- .002 normal?

[RickyRodney]

I just got done resizing my .308 federal brass x1 fired and and it been varying .002 smaller and larger. I'm not sure if that is normal or if there is commenting I can do making my brass more consistent. I'm using a standard RCBS FL resizing die. I'm just tightening it down in my lee classic press.

 

[spife7980]

How are you measureing? What are you measuring? The answers to those will inform my next question of how much are you sizing your brass down?

 

[Bradu]

Pull the expander ball out and see what happens with the measurements.

 

[ShtrRdy]

I recently resized some Federal .308 brass. I didn't pay attention to different lengths because all the pieces need to be trimmed.

 

[RickyRodney]

I have donated (to me) brass fired from 2-3 rifles. Some of the brass is at length already and the die is just sizing the neck I believe. But generally .001-.004. I'm measuring with hornady calipers and hornady case gauges and I have the anvil for it too. The gauge indexes I believe on the datum line. I'll see what happens without the expander ball.

 

[RickyRodney]

I'm not measuring OAL.

 

[supercorndogs]

So, are you having .002 variation or .004 variation? .002 I would not worry about between the largest and smallest measurement, .004 I would.

 

[Danattherock]

Ricky, it's to be expected. Varying brass, you dont know which ones are even being sized. Some maybe shorter than your die is setup. After firing, this will likely self correct. At some point, buy brass and use from same lot. Quality brass preferably. Along with Hornady headspace gauge kit, calipers, bumping shoulders 2 thou, etc. Things will be simpler this way. But as said, after fire forming, you will have less head aches also. But for accuracy, you will eventually want to consider some Alpha Munitions or Lapua brass in my opinion. It's just far more consistent.

 

[supercorndogs]

Ricky, it's to be expected. Varying brass, you dont know which ones are even being sized. Some maybe shorter than your die is setup. After firing, this will likely self correct. At some point, buy brass and use from same lot. Quality brass preferably. Along with Hornady headspace gauge kit, calipers, bumping shoulders 2 thou, etc. Things will be simpler this way. But as said, after fire forming, you will have less head aches also. But for accuracy, you will eventually want to consider some Alpha Munitions or Lapua brass in my opinion. It's just far more consistent.

It is not likely any brass remains unsized if he screwing the die all the way down in his press. You don't find many chambers smaller than that.

 

[Milo 2.5]

I have donated (to me) brass fired from 2-3 rifles. Some of the brass is at length already and the die is just sizing the neck I believe. But generally .001-.004. I'm measuring with hornady calipers and hornady case gauges and I have the anvil for it too. The gauge indexes I believe on the datum line. I'll see what happens without the expander ball.

Some general reasoning here, even if you had bought new brass, all the same lot and fired it once in your rifle your measurements may look or be the same. You're trying to uniform brass fired in 3 different rifles, I would shoot for a minimal bump and fire the 2nd time and then measure.
Unless the brass you got free had been sized by someone else, a uniform bump should have been done before you fired it yourself, even if bolt closure may have been tight on a few.
You need to get your brass a uniform size before worrying about anything here, I'm giving you the benefit of the doubt you lubed your cases the same while sizing.

 

[Danattherock]

Agree ^^

Super corndog, my thought was some of his donor brass could have been sized before he got it.

 

[Milo 2.5]

Not trying to bust your balls here, but if you desire accuracy from your rifle, you do not start out with brass fired in 3 different rifles. The Federal brass may be just fine, but the deck is stacked against you. If brass still has service life, you can transfer brass from one chamber to another, if it was controlled by yourself only.

 

[RickyRodney]

Okay so I measured the brass and it has been varying from 1.618-1.622. So I split it into 2 lots. Same powder charge, ogive and bullet.

-Mr. Corndog yes I lubed the brass and yes it has a .004 spread.

I measured my now x2 fired brass out of my DTA (the rifle I'm loading for) and it measures 1.620-1.622. So I assumed some brass that I sized fine and some brass I need to resize but it all chambers so I'm just going to shoot it. And see how it stacks up.


I understand how the brass forms to the chamber and that explains the variations of size pre-resizing, but if I have the die set to smaller than any of the fired brass why is there so much variation? PS when should I anneal? This brass started life as FGMM.

 

[918v]

When you size, is the shell holder touching the bottom of the die? If not, the variance is due to press frame/linkage springing/stretch.

 

[RickyRodney]

yes I believe it was

 

[XLR308]

If I personally was going to conduct sizing with the same situation you previously posted I would do the same as I do with new brass I intend to neck turn.
I would sort them into lots from base to shoulder, you would end up with a majority that are very close depending on the dimensions of the chambers they were fired in with a smaller amount just under or over and size them all to the majority measurement minus whatever headspace you need or want.
The simplest and best answer of course is to start with new brass or brass fired only in your rifle.

 

[918v]

yes I believe it was

You need to be sure. Run an unsized case into the die and look for light between the die and the shell holder.

 

[Danattherock]

After you fireform all this brass in your rifle, things will get simpler. At some point buy some Alpha Munitions or Lapua brass. I anneal every 3rd firing and my SD stays between 3-6 in several calibers. I use Anneal-Eez which is only $275, works great for my needs. Quality dies, like Redding bushing type S full size set with micrometer inline seater, and quality brass, have taken much frustration out of my reloading routine.

 

[Reload10]

Redding competition shell holders will help reduce your variance. Jeff Brozkovich at long range only has a good tutorial on them.

 

[RickyRodney]

When you size, is the shell holder touching the bottom of the die? If not, the variance is due to press frame/linkage springing/stretch.

If the shell holder touches the bottom of the die, do I adjust the shoulder bump? I thought the decapping pin and expander ball had nothing to do with shoulder to case base length?

 

[RickyRodney]

Here’s the die

 

[918v]

If the shell holder touches the bottom of the die, do I adjust the shoulder bump? I thought the decapping pin and expander ball had nothing to do with shoulder to case base length?

We’re not talking about decapping pin and or expander ball. We’re talking about consistent shoulder bump. If your shell holder is not touching the bottom of the die with the case in it then your press frame and handle linkage is stretched. This is the cause of your variance.

Adjust the die (loaded with a case) for hard contact with the shell holder. Measure the shoulder. Compare that reading to your fired case.

 

[RickyRodney]

Rodger that....standby