Why we plunk rounds.

[newageroman]

Explanation of why I plunk rounds on Rumble. Run the same ammo in all barrels, but you gotta check! this is why...
https://rumble.com/vuylzb-reloading-9mm-why-we-plunk-rounds-124precision-deltas-and-naas3-cases.html

[Wobbly]

A full explanation already existed on... you guessed it... The Original CZ Forum !!

[newageroman]

Well yeah, but I didn't see any on Rumble specifically so now there is one there too.
Tricks I learned here.

[IDescribe]

Point of interest:

9mm brass almost never meet spec on length.  Unless you are using brand new Starline, your brass are likely headspacing on the extractor instead of the case mouth. 

[newageroman]

excellent point! I would think that would keep your ogive farther away from the rifiling?

[Clint007]

Does typically used pistol brass ever stretch too long?

[SoCal]

Almost never...I just cannot say NEVER EVER EVER.

[tdogg]

What I've found through roll sizing is that the brass shortens due to the base expanding (just above the extractor groove).  Typical 9mm cases generally are in the sub 0.740 inch length range post firing.  When you full length resize them they may grow back a little to sub ~0.745 inch or so.  When you roll size them, they grow back to ~0.750 inch.  Conservation of mass rings true, if you stretch the base the brass has to come from somewhere.

The folks at Rollsizer.com don't recommend using a undersize die along with rollsized brass.  I think you could potentially run into cases that are too long.  I haven't yet but it's possible.

Pistol cases don't stretch rearward when fired like a bottle neck rifle cartridge.  They just fill the chamber radially and hence they shorten over time depending on how sloppy the chamber is that is firing them.

Cheers,
Toby

[Wobbly]

What I've found through roll sizing is that the brass shortens due to the base expanding (just above the extractor groove).  Typical 9mm cases generally are in the sub 0.740 inch length range post firing.  When you full length resize them they may grow back a little to sub ~0.745 inch or so.  When you roll size them, they grow back to ~0.750 inch.  Conservation of mass rings true, if you stretch the base the brass has to come from somewhere.

The folks at Rollsizer.com don't recommend using a undersize die along with rollsized brass.  I think you could potentially run into cases that are too long.  I haven't yet but it's possible.

Pistol cases don't stretch rearward when fired like a bottle neck rifle cartridge.  They just fill the chamber radially and hence they shorten over time depending on how sloppy the chamber is that is firing them.

Cheers,
Toby

Hold on. I'm still looking for the "Like" button.