Full length Resizing 9mm?

[Palladan44]

Original dillon 550B manual says to set up the resizing die by raising the shell plate, screwing in the die into the toolhead until the die touches the shell plate, then back off just a bit, say 1/4 turn.

This has always made sense with straight walled cases, but how about 9mm Luger?
I know I'm doing no harm, because they always turn out fine, but I'm wondering if 9mm Luger is supposed to possibly be sized only partial the way down? Say 3/4 the way?
Please let me know your thoughts.

 

[LiveLife]

I am loading on Dillon 550C and Lee ABLP/Pro 4000 and adjust the resizing dies until I don't see daylight between bottom of die and top of shell plate while resizing.

Or you can adjust the resizing die until all the resized brass pass the case gage.

 

[25-20 WCF]

As a tapered case, partial resizing might not reduce the diameter if the case mouth enough to firmly hold a bullet during cycling. It is best to fully resize those cases to insure proper functioning.




.

 

[AJC1]

I have only seen partial or bump sizing on rifle. I size pistol as far as I can. If I could afford a roll sizer I'd do that.

 

[joneb]

I find partially sized cases are sometimes limited to the chamber the case came from.

 

[lordpaxman]

Please let me know your thoughts.

For better or worse, I follow the manufacturers instructions on this one. I’ve always tried to get as much of the 9mm case sized as I can, and have seen no ill effects from it. BTW this is either on a LNL or RL1100. Good luck.

 

[JEBruns]

I size them all the way down. Actually, since my Dillon 1100 has an extra station, I size them twice. Once with a standard RCBS carbide die and next with a Lee "undersized" die. My Shadow 2 Orange is kind of picky. Reloads that just barely fail my Hundo gauge test will fire okay in most of my guns, but not the S2O. The Lee die makes it so virtually all of my reloads pass the Hundo test.

You could, of course, run the Lee die as your only resize die. But since I had the room on my tool head, if figured I'd 2 step it.

 

[WeekendReloader]

I fully size 9mm cases. If the die is not screwed down far enough, sometimes the case won't fit in my case gauge.

 

[jmorris]

I run the die down until it sizes brass to fit the case gauge and stop.

If I go further than that, the tapered 9mm case gets sized more than necessary and when I seat a bullet it looks like an old glass coke bottle, skinny in the middle and fat on both ends. They still shoot fine that way but I prefer my ammunition to look right.

If your final product looks like this,



You are sizing the case more than necessary.

 

[mdi]

There's a lot of talk about sizing 9mm Parabellum cases. Most sizing dies are just sizing the case straight, without the normal taper, about .011" from case mouth dia. (SAAMI .380") to case just in front of extrating groove (.391"). Some may partially size the case to "keep" taper. Some dies include the taper but are either steel or $$$ carbide. In real life, just use the die manufacturer's instruction. You will not notice any problems (I have been reloading 9mm for over 30 years, a lot, for 5, 9mm handguns, one revolver and 4 semi-autos using Lee carbide sizing dies followed by a plunk test. No problems chambering, no feeding problems, and no short case life)...

 

[Palladan44]

I run the die down until it sizes brass to fit the case gauge and stop.

If I go further than that, the tapered 9mm case gets sized more than necessary and when I seat a bullet it looks like an old glass coke bottle, skinny in the middle and fat on both ends. They still shoot fine that way but I prefer my ammunition to look right.

If your final product looks like this,

View attachment 1037346

You are sizing the case more than necessary.

This is basically the reason why it aggravates me is the "hour-glassing" of the finished cases. And a lot of times, although the finished cartridges are well within spec. (Usually tighter than factory ammo actually) sometimes there's an obvious bulge off to one side. A sleeved seater die(redding competition die) does NOT fix the problem. A proper fitting seater stem does NOT fix the problem either. Doesn't matter how I lock down the die, the hour glassing still occurs, and many times it is visually assymetric, meaning the bullet is not sitting in perfect alignment with the case. Again, it still meets spec, but I sure don't like it.

Lastly, it's a safe guess that a lot of my 9mm brass (mostly once fired range brass I buy from a local guy for basically scrap price) has been fired through Glock barrels (or similar weapons with very generous chamber tolerances) which almost always bulge the brass asymettrically down near the case head. This problem becomes worse in 40 s&w and 10mm, both which I also load for...
I have to wonder if the original assymetrical fire-forming has something to do with the assymetrical seating in the case...

 

[gwpercle]

If it isn't broke ... don't fix it .

You followed the directions exactly and everything is working fine ...that's great ... should you disreguard the directions and screw the die all the way down untill it makes contact like you set up a Single Stage Press ...
Sure ...Go for it ...let us know how setup #2 works ...better ?
Gary

 

[LiveLife]

why it aggravates me is the "hour-glassing" of the finished cases

It shouldn't as it indicates good neck tension to minimize/prevent bullet setback. 9mm 115/124 gr FMJ/RN have shorter bullet base and can suffer from neck tension/bullet setback issues and slight undersizing and seating these bullets deeper (Say 1.130"-1.135" vs 1.150") help with bullet setback and in my testing produced smaller groups.

sometimes there's an obvious bulge off to one side.

One-sided bulge could indicate tilted bullet during seating and proper flare that allows bullet base to just set inside the flare helps minimize one-sided bulge around case neck.

a lot of my 9mm brass ... bulge the brass asymettrically down near the case head.

I have to wonder if the original assymetrical fire-forming has something to do with the assymetrical seating in the case...

Not sure if two are related but when I resize brass and feel additional resistance, I suspect overly expanded case base/fired 9mm Major case and will inspect the case and toss for recycling if I detect any concerns. If the resized case won't pass case gage/tightest chamber barrel, I will attempt to resize again but will toss for recycling if it fails the second time.

With USPSA 9mm Major a reality with many match shooters leaving unmarked 9mm Major brass on the ground/range floor, it is a new reality us reloaders must factor into our reloading process for 9mm.

should you disreguard the directions and screw the die all the way down untill it makes contact like you set up a Single Stage Press

Not if you are not experiencing any chambering issues.

But if you are having chambering issues or resized brass not passing case gage issue, it could be from shell plate deflection/tilt and if that's the case and you see daylight between the bottom of die and top of shell plate during resizing, you may need to compensate for the deflection/tilt perhaps from press wear/slop if tightening the press won't eliminate the daylight.

 

[jmorris]

…weapons with very generous chamber tolerances) which almost always bulge the brass asymettrically down near the case head.

Yeah but you don’t have to squish the middle and up of the case too much to put it back to spec. You just roll size the rim, extractor groove and base before you size with a regular die, set correctly.

I have to wonder if the original assymetrical fire-forming has something to do with the assymetrical seating in the case...

If it were a matter of that, us guys that use mixed range brass would have some look wrong too.

That said, some bullets are harder to seat perfect than others and that is also stem dependent. When everything is just right and I am using one of my GSI feeders, I can seat coated bullets perfectly straight, with very little flare.



That case on the left is ready for the bullet to be seated, the one on the right is seated waiting on the “crimp”.

 

[mdi]

No one sees my handloads other than myself. I am much more concerned with functional, accurate handloads than "pretty" ammo. Hourglass, waspwaist, assymeteical (I seat bullets with my RCBSseater die and as long as I seat the pullet straight they go in my M-die flared cases straight.) is of no real concern because all my handload dimentions are passing the plunk test during the initial load work up. I have an old Norinco Tokerev 9mm with "generous" chamber and brass fired in it gets the same treatment as those fired in my "tight" chamber Masada and function quite well in all 5 of my 9mm handguns. Once they are tumbled, sized and flared,mostly in mixed brass lots, they are as I dentical as I can measure...

 

[LiveLife]

No one sees my handloads other than myself. I am much more concerned with functional, accurate handloads than "pretty" ammo. Hourglass, waspwaist, assymeteical ... is of no real concern because all my handload dimentions are passing the plunk test during the initial load work up

Same here.

When I started reloading, I wanted my finished rounds to look like factory with shiny brass and straight case necks without bulges showing.

But shooting USPSA matches, I realized shiny brass and "nice" looking rounds don't necessarily produce accuracy but finished rounds with good neck tension did (Yes, it's the "chambered" OAL that matters and holes on target speak volumes) so I just focused on clean brass with reloading process that minimized/eliminated bullet setback to optimize accuracy.

So when I see "Coke" bottle effect on finished rounds but with even bulging around bullet base on case neck, I see good neck tension that will produce more consistent groups.

 

[wtf808]

Meh just run your press as directed… I used to think the coke bottle effect was only Dillon dies but not anymore. I full stroke it in my 750 and everything that comes out of it shoots just fine in my various guns. Your results will be your own. Good luck!