9X25 Headspacing

[pop_a_cap]

Guys,
First post so go easy..

I am tired of searching and going to make an assumption the Dillon headspaces off the shoulder and not the case mouth?

Someone set me straight.

thanks

pop a cap

[sqlbullet]

99% certain it is the shoulder.

[pop_a_cap]

I was too and finally found one post last night where I guy said shoulder.

thanks for the reply.

[The_Shadow]

Pop_a_cap, welcome to the forum.

Here is what I do with mine, I size the casing for the chamber.  The Dillon dies can oversized and set the shoulder back too far and that can lead to case splits and neck separations.

I try to get the brass to be FLUSH to the barrel hood as possible 0.000" flush, but no more than 0.002" below the barrel hood.
This provides the proper spacing and helps keep the case neck splits to a minimum!

Understand the working the brass through the sizer induces work hardening (make brass brittle) therefore you will still see an occasional split or a casing that will not hold the bullets tight.

Using bullets designed for the 357Sig or bullets with straight sides will also help prevent setback issues.  Some of the regular 9mm 0.354"- 0.355" bullets can be a loose fit or their radius noses extend too low on the bullet at their base to provide the best fit, seal and accuracy.  I have used some Jacketed bullets sized at 0.356" from Zero Brand bullets that were sold for the 38Super with good results.  I even tested a few jacketed bullets at 0.357" without issues.

I also have used my own cast alloy bullets sized to 0.3565" that have worked well.

I hope this helps, if you need more help or have questions feel free to respond.   

[pop_a_cap]

The_Shadow,
Thank you for the good info.. I've been shooting and reloading the 9X25 for almost two years however I have mainly used XTP bullets.
it was yesterday that I experienced my first bullet setback and a few ftf's due to headspacing.  The setbacks occurred with Zero 115gr fmjs.

Looks like the ogive extends a bit farther than most which is killing my neck tension.

Unfortunately I have several hundred of these loaded up so I hate to pull them.  They are currently seated to 1.259 and I'm going to use my kinetic puller to get them out to 1.262 then try a bit more taper crimp.. I'll do this on a few then shoot them. If setback occurs again I'm pulling the entire lot.

I'm waiting on a knurling tool to arrive and may try that if load these bullets again or just stick with XTP's.

What bullet(s) do you have the best luck with in your Dillon? 

[The_Shadow]

Yes, it was me on the 10mmfirearm forum.
The bullet choices can plague the neck tension and where the crimp will hold.  What neck expander are you using?  I'm using my RCBS 9mm expander for this process which had left a good neck tension in the case neck.  Using it I have not had any issues with cases crushing, the necks stay very straight even with the cast bullets.

The only thing about seating long is introducing failures to feed or even having the bullet pop out the casing during cycling, if it comes loose with the lack of fit.

Looking for bullets with straighter sides or diameters of 0.356", can help maintaining a snug fit and neck tension.  As I mentioned on the other forum I have even used some Jacketed 0.357" bullets with success.

The bullets designed for the 357Sig are better suited for the neck tension overall by design.  Most 9mm bullets will frag really badly at the speeds of the 9x25.

[FLYDAD]

So I now have 400 Starline cases and that I have formed, loaded and shot. It's time to reload them. I am using a Dillon 550 and the 9 x 25 die set, with a Lyman M die which worked great for the first loading's. Any pitfalls to be aware of with these as I reload them? 

[The_Shadow]

FlyDad, If this is the first time you are using the Dillon Sizer die, check the sized cases for headspacing.  Do not over size the casing where you set the shoulder back too far.

This is crucial to your brass longevity by avoiding overworking the brass when shooting and sizing.  You will want the case head as close to flush with the barrel hood @ 0.000" but no more than 0.002" below.  Even doing everything right you will still likely see a few split or even separate the neck.

Not all bullets are suitable for the short neck of the 9x25 as previously mention due to the ogive of some bullets...