338 LM ELR Reloading Thread

[BigNate]

12 hours ago, Magwa said:

sorry been out of town in the mountains no cell coverage Ok you are reducing your neck to 3 thou.... but you mandrel only opens it to two thou.. you sizing die should resize the neck on the outside to 338 then you use the mandrel and open it for 2 thou. size.....call me if you are confused or I am confused LOL

Thanks @Magwa Congrats on being off-line! I was in the woods this weekend too (up on the rim - cabin time) - but unfortunately they've put in a new cell tower so I'm no longer totally detached when there.   

I think we're saying the same thing - other than that I'm resizing the neck from the outside down to 0.365 (based on wall thickness this gives me an ID of 0.335) which then gets opened up to 0.336 by the mandrel...  If I shrink the OD to 0.338 it would take the the ID down to 0.308 which would then get opened back up to 0.336 by the mandrel.  My thought is that I want to minimize the amount of movement of the material to reduce the amount that it work-hardens during the sizing process. I do feel minimal resistance when I push the neck over the mandrel - so I believe that it is opening up the neck very slightly - and there is enough neck tension on the seated bullets that I'm not worried about them moving prior to being chambered - and given that I'm single feeding these I'm not worried about them getting jostled around in the magazine etc. 

The variables are as follows: 

• Case Neck Material Thickness - 0.015 (measured at the reloading supply shop on new brass - I wamt to get a vernier ball micrometer so I can do it myself as the brass thins).
• Case Neck OD of once fired brass ~0.369" (I'm guessing at this - but I can drop a bullet into the neck of a fired case and it will slide into the case - so I'm guessing the ID is 0.339ish - plus the 0.030 of the two neck walls)
• Case Neck OD after resizing with the bushing die - 0.365
• Case Neck ID after resizing with the bushing die - 0.335 (0.365 - 2X0.015) 
• Case Neck ID after resizing with the mandrel - 0.336 - giving 0.002 neck tension on a 0.338 bullet

So - the idea is that I'm only shrinking the neck by 0.004" and then expanding it by 0.001" to get it to where I want it to be for the 0.002" neck tension... If I resized down to 0.338 OD - I'd be shrinking it by 0.061" with the resizing die, then opening it back up by 0.028" with the mandrel - moving the material a ton more, increasing work hardening, and reducing brass life (or at least that's what I "THINK" would be happening).   I'm trying to move the material as little as possible - to get as much life out of the brass as possible.   Does that make sense? 

[Magwa]

ok got ya but you are annealing after every firing correct? so in my reloading for this I am decapping old primer then annealing then resizing with no ball or decapping pin in resize die then I use mandrel and it opens case mouth 2 more K are we doing the same thingLOL i just did not understand you saying you used a bushing to size down to 3 K then used a 2 K mandrel which would do nothing ? so I guess I am confused.lol if it is working then get er done...

what does your resizing die size the neck to ? it should resize to sammi spec right? 

[BigNate]

1 hour ago, Magwa said:

ok got ya but you are annealing after every firing correct? so in my reloading for this I am decapping old primer then annealing then resizing with no ball or decapping pin in resize die then I use mandrel and it opens case mouth 2 more K are we doing the same thingLOL i just did not understand you saying you used a bushing to size down to 3 K then used a 2 K mandrel which would do nothing ? so I guess I am confused.lol if it is working then get er done...

what does your resizing die size the neck to ? it should resize to sammi spec right? 

I think we're doing the same thing. 

• Yes I anneal every time.   
• I then resize and bump the shoulder using a match resizing die with a bushing that takes the neck ID to only one thousandth smaller than the mandrel (and with no ball on the decpping pin) - so 0.003 smaller than the bullet diameter. 
• I then push the case over the mandrel opening the neck to where it is 0.002 smaller than the bullet diameter. 

So - I'm just using a bushing die to shrink the neck instead of a standard sizing die - so I suspect that I'm moving the neck material less. 

 

EDIT - I don't have a standard sizing die - but I did some digging and Google tells me: "The outer diameter (OD) of a .338 Lapua Magnum case neck after being sized in a standard full-length die without an expander ball is typically between .324 and .326 inches." If that's true - and the neck wall thickness is 0.015 then the ID of the resized case (before the expander mandrel) would be 0.294 - 0.296" - so pushing it over the mandrel is going to open it up by 0.040.  I'm thinking that as a general rule moving the brass less is better... so unless I see a reason to change - I'll keep using the bushed die (without any expander ball) to shrink the neck... and the mandrel to final size it...  

Edited September 10 by BigNate
more info

[Magwa]

22 hours ago, BigNate said:

I think we're doing the same thing. 

• Yes I anneal every time.   
• I then resize and bump the shoulder using a match resizing die with a bushing that takes the neck ID to only one thousandth smaller than the mandrel (and with no ball on the decpping pin) - so 0.003 smaller than the bullet diameter. 
• I then push the case over the mandrel opening the neck to where it is 0.002 smaller than the bullet diameter. 

So - I'm just using a bushing die to shrink the neck instead of a standard sizing die - so I suspect that I'm moving the neck material less. 

 

EDIT - I don't have a standard sizing die - but I did some digging and Google tells me: "The outer diameter (OD) of a .338 Lapua Magnum case neck after being sized in a standard full-length die without an expander ball is typically between .324 and .326 inches." If that's true - and the neck wall thickness is 0.015 then the ID of the resized case (before the expander mandrel) would be 0.294 - 0.296" - so pushing it over the mandrel is going to open it up by 0.040.  I'm thinking that as a general rule moving the brass less is better... so unless I see a reason to change - I'll keep using the bushed die (without any expander ball) to shrink the neck... and the mandrel to final size it...  

I think we are doing the same thing in different ways but the key thing is we are both achieving consistency and that is what we are after our neck tensions may well be different but by doing it the same every time we get what we want... awesome.