Should my expander die be shortening my brass,

[Tikkat1x]

Evening chaps, i recently got a APW expander mandrel and iv noticed its shortening my brass by 0.005"
now it came with no instructions and just a poor video on there website, so i set it till it just sat on the neck then let it do down another 6-8 mm just so it only just expanded the neck, so i think its set up ok, but im guessing it shouldn't be shortening it, im not noticing any over exertion when expanding the necks, I'm 5 reloads into some new Lapua 243 brass that iv not had to trim yet, and I'm still at min brass length,

thanks.

Lee

 

[ColinBr]

Can you back the die off an 1/8th of a turn, and see if it still does the same?

 

[Tikkat1x]

Can you back the die off an 1/8th of a turn, and see if it still does the same?

tried that mate, but it was a good half turn. but still the same,

 

[ColinBr]

Do you possibly have the expander mandrel itself going too deep and it is then pushing the neck down?

I haven't used mine yet, so I'm only guessing here.


Maybe @Ronin could help

 

[Tikkat1x]

Do you possibly have the expander mandrel itself going too deep and it is then pushing the neck down?

I haven't used mine yet, so I'm only guessing here.


Maybe @Ronin could help

possibly, i actually didnt back the die off, just the mandrel, i will try backing the die off when i next use it, no old brass to try at the moment, but the body is not in much anyway

 

[deeangeo]

Sound like you're 'Oversizing' your brass - you should be sizing to 'Fired Case Headspace' dimension

 

[Ronin]

Die shouldn’t contact the case only the mandrel

 

[Tikkat1x]

right chaps, still getting know where, unless i back it off so far that the mandrel isnt even doing its job, i will try a better explanation with pictures,
so the die is just a tube so it cant be crushing on that, the screw in mandrel is the only thing that could come into contact with the brass, iv tried screwing the die body out, no joy, iv tried raising the mandrel, and it only stops when it seems like the mandrel is not going into the neck, so maybe in not the correct order but my pictures show, the press just as it touches the neck, then one ant the end of the stroke, the inside of the die, how far the mandrel is going in when im done, how the whole unit sits in the press and last one shows where my brass sits and how far down the mandrel does down showing (in my eyes) that the brass cant be touching the top of the mandrel, i then thought it might be forcing it down whilst the mandrel went in but iv tried wet lube and dry lube,
im not far off putting the expander ball back in my resizing die

 

[Tikkat1x]

.

 

[Ginc]

Your full-size die reduces the neck to a significant undersize. I recommend using two different-sized mandrels to gradually restore the neck or considering a more tapered mandrel from a different manufacturer.

 

[Ginc]

I size my Lapua .243 Win brass using a Redding body die, followed by a Lee collet neck sizing die. It works perfectly, requiring minimal force at each step.

 

[MarinePMI]

Maybe this is a daft question, but is the shorter .005" case affecting accuracy?

If not, then is it really a problem?

 

[ColinBr]

Maybe this is a daft question, but is the shorter .005" case affecting accuracy?

If not, then is it really a problem?

You are adding more for the case to stretch though in the chamber and then reducing brass life

 

[MarinePMI]

You are adding more for the case to stretch though in the chamber and then reducing brass life

Only if the shoulder is getting pushed back that much (which I seriously doubt). More likely, the neck is getting push down by the mandrel, causing the shoulder to slightly buckle. So long as the majority of the shoulder remains in place, the difference in length will not affect case growth/stretch that much.

To the OP: Are you lubing the inside of the case necks when you expand? By chance, are these freshly wet tumbled brass? (squeaky clean brass can sometimes get sticky with expanders).

 

[Tikkat1x]

Your full-size die reduces the neck to a significant undersize. I recommend using two different-sized mandrels to gradually restore the neck or considering a more tapered mandrel from a different manufacturer.

i used the other size and it did the same,

 

[Tikkat1x]

Maybe this is a daft question, but is the shorter .005" case affecting accuracy?

If not, then is it really a problem?

probably not, but wasnt sure if it should of been doing it or not, and weather it was putting undue strain on my new Lapua brass,

 

[Tikkat1x]

Only if the shoulder is getting pushed back that much (which I seriously doubt). More likely, the neck is getting push down by the mandrel, causing the shoulder to slightly buckle. So long as the majority of the shoulder remains in place, the difference in length will not affect case growth/stretch that much.

To the OP: Are you lubing the inside of the case necks when you expand? By chance, are these freshly wet tumbled brass? (squeaky clean brass can sometimes get sticky with expanders).

its not affecting the shoulder, its the same as it was when i bumped it back in the die, iv tried a carbon dry lube, and iv tried a spray lube, and before they were resized they had been in the ultrasonic cleaner, then annealed,

 

[MarinePMI]

its not affecting the shoulder, its the same as it was when i bumped it back in the die, iv tried a carbon dry lube, and iv tried a spray lube, and before they were resized they had been in the ultrasonic cleaner, then annealed,

Hmmm...so if the shoulder hasn't changed position, brass life shouldn't be affected. I'm wondering if by expanding the neck, the neck itself is shortening (if the neck ID is getting bigger, then the material has to move somewhere, but usually it gets thinner, not shorter). But .005" is a lot of movement (that's almost a quarter to a third of the thickness of the neck itself). How are you measuring the lengths?

 

[Tikkat1x]

Hmmm...so if the shoulder hasn't changed position, brass life shouldn't be affected. I'm wondering if by expanding the neck, the neck itself is shortening (if the neck ID is getting bigger, then the material has to move somewhere, but usually it gets thinner, not shorter). But .005" is a lot of movement (that's almost a quarter to a third of the thickness of the neck itself). How are you measuring the lengths?

M-sure digital callipers,

 

[ColinBr]

So it's not the shoulder that you are measuring?
Your measuring the OAL of the case?