Inconsistent 9mm seating pressure

[Drvred]

I am loading 9mm on a RCBS turret press with Lee dies.
The pressure it takes to seat and to crimp bullets is all over the place, from non existent, to a fair amount.
Most of the brass has been run through my pistol, (a Tisas Stingray) but some are range pickups.
What am I doing wrong, and how do I fix it? I don't notice it in my 45 brass.

 

[Catfish]

With mixed brass you can expect some inconsistencies. Have you checked for neck tension issues in the ones that felt looser? That will tell you if you have a problem or not.

 

[Timfoilhat]

This is why I sort my headstamps.

 

[Toprudder]

I ran into that problem with 10mm range pickup brass. The PPU brass had thinner walls than the other brass I have tried.

The 9mm brass with the internal steps can be a real pain when resizing. I inspect for those and toss them now, not worth messing with.

 

[GymB]

The inside diameter of thicker brass is smaller once resized, that might account for the seating pressure. Can’t imagine the problem with a standard taper crimp die, maybe you got sucked into the cult of the lee factory crimp die?

 

[Drvred]

The inside diameter of thicker brass is smaller once resized, that might account for the seating pressure. Can’t imagine the problem with a standard taper crimp die, maybe you got sucked into the cult of the lee factory crimp die?

I have the 4 die carbide set, same as my 45 dies which don't seem to have the same issue.
I will start sorting by headstamp.

 

[Catfish]

Again, what issue are you having? ‘Feels different’ isn’t an issue by itself.

I been doing this for a while now, and if I had to sort 9mm by headstamp I’d trash the whole setup. That sounds… miserable.

 

[Drvred]

Again, what issue are you having? ‘Feels different’ isn’t an issue by itself.

I been doing this for a while now, and if I had to sort 9mm by headstamp I’d trash the whole setup. That sounds… miserable.

Some cases have no resistance while seating and crimping bullets.

 

[71Ragtop]

I sort everything by head stamp as the first step in brass prep. My Six Sigma self sees it as eliminating an opportunity for error. Yes, I have buckets of mixed 'stuff' that someday I will get bored enough to sort but that won't be anytime soon.
Plus I shoot my reloads at my range so I really only have to sort once. None if I really pay attention shooting factory ammo but being cheap that doesn't happen much.

 

[GymB]

Some cases have no resistance while seating and crimping bullets.

No resistance when seating implies no neck tension, bad thing. Before crimping one of those remove it from the press after seated and see if you can pull or twist the bullet by hand compare the cartridge to one that had resistance and see of they are both similarly wasp-waisted. Also worth checking to see if the bullets are the same diameter.

 

[beamernc]

Check your bullets. I seen some that were in spec just at the base, but undersized just above the base.

What type bullets? Are they by chance Armscor 124 gr FMJ?

 

[Drvred]

No these are 115 XTPs.

 

[GymB]

No these are 115 XTPs.

I’ve had no issues with those.

I guess get 50 pieces of brass, all the same headstamp, and see if that solves the problem.

 

[Snoopz]

Which headstamps are causing the issues? (the same ones?) Sort them out (yeah I know a pain)
Stepped internal case (or what they call a shelf)? (generally scrap pile)
Is this happening to the brass fired out of your pistol? or just the range brass? or both?
Take the ones that are an issue look to see the thickness of the brass in the mouth is thinner than others
if you have calipers do some quick measurements, case mouth inside diameter, case length, etc.
Are the range pickups fired too many times, (this you probably wouldn't know) most times it's left for a reason.

next up would be die adjustments, move the sizer to a different spot in the turret. if the bullet tension is all over the
the place with different brass, could be die adjustment or flex of the press / turret.
Out of spec sizer..(it does happen)... taper crimp (not adjusted properly) dies not "locked down"
just tossing things out there, firearm really shouldn't matter

Now here I sort all my brass, at this point I have to a ton of Mil "crimped brass", it's a pain but one and done, then the
odd ball headstamps, those are pretty much the shoot n loose pile, if I leave brass behind and you find it, you better
"scrap it" There is some brass around here Mixed headstamp (fired once) I just do a quick inspection, load and go.
As far as dies it's RCBS Carbide set, Mighty Armory (use the most, try a set and you'll see) use the MA Gold Match Sizer,
Expander / Flare, and seater, taper, not one issue (they ain't cheap but work), then it's my ole standby's Lyman "M" die
for cast, "plated" bullets, CH Tool & Die (CH4D now) Taper crimp. MiHec brass molds for casting.

Bullet wise.. I stay clear of Armscor, some of the early Berry Plated pistol bullets, and some "lesser known" Makers, way to
much deviations in diameter, Hornady should be okay, while not a fan of their brass or bullets, years ago maybe.

Firearms wise... it's a range ... a laundry list....

-Snoopz

 

[Toprudder]

The inside diameter of thicker brass is smaller once resized, that might account for the seating pressure.

The inside diameter should end up being the same after the expander, at least at the case mouth. But, many times the bullet ends up being seated deeper into the case than the expander (particularly with heavier/longer bullets).

 

[GymB]

The inside diameter should end up being the same after the expander, at least at the case mouth. But, many times the bullet ends up being seated deeper into the case than the expander (particularly with heavier/longer bullets).

Lee dies, relatively shallow expander.