"Belling" 9mm


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OldGunMan
April 4, 2012, 02:16 PM
Is it necessary to "bell" the case mouth on 9mm reloads if:

1. you chamfer the inside of the cases, and -

2. you are reloading jacketed bullets?

Thanks,

Bruce

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788Ham
April 4, 2012, 02:45 PM
Yes, it will keep you from crushing the cases. Bell just enough for the bullet to be accepted into the case mouth, able to lift the case by the bullet, might need to tweak it a tad bit.

rcmodel
April 4, 2012, 02:54 PM
+1
I bell just enough to hand start the bullets in 50 charged cases in a loading block after checking powder levels in all of them.

Want to be able to pick them up at the press to seat them without the charged cases falling off and spilling the powder.

rc

Blue68f100
April 4, 2012, 04:09 PM
It's best to use some but if your jacketed bullets have a radius bottom it may not be needed. I normally use the expander to get a more uniform neck tension. But if your dealing with Rem brass you may not need to since the case wall is thinner.

gamestalker
April 4, 2012, 04:24 PM
No it is not necessary. I haven't belled the mouths on any cartridges in a good 30 years, and I have never crushed a case, or other wise had a problem since. As you stated, as long as you ream and chamfer the mouths, jacketed bullets slide right in without any issues.

If the mouths are lightly prepped with a ream and chamfer the bullets will set up straight on the mouth, start straight, and seat with full neck tension and eliminate the need for crimp to close the belling. And if you consider the decrease in working of the brass, brass life does increase a bit as well.

Fishslayer
April 4, 2012, 04:29 PM
I bell all pistol brass to where the bullet will just sit atop the case. More than that and you are working the brass more than necessary & can shorten case life.

I cringe at the thought of chamfering every one of my 9mm cases...

GLOOB
April 4, 2012, 04:33 PM
prepped with a ream and chamfer
How do you ream the cases? Is this like neck turning from the inside?

GLOOB
April 4, 2012, 04:34 PM
I cringe at the thought of chamfering every one of my 9mm cases...
Chamfering each case might not be so bad if you load on a single stage press. That could eliminate a lot of flaring over the lifetime of the brass. Except 9mm brass is kinda hard to keep track of.

Fishslayer
April 4, 2012, 04:45 PM
Chamfering each case might not be so bad if you load on a single stage press. That could eliminate a lot of flaring over the lifetime of the brass. Except 9mm brass is kinda hard to keep track of.

I cringe at the thought of trying to keep up with my wife's 9mm habit with a single stage press! Even with our 10 round mag limit (I bought her a few extra for her SIG) she really burns through the stuff!:what:

I get quite a bit of "incidental bycatch" when policing my brass so I never really know which is which, how many times reloaded, etc. What (very) few split cases I come across just go in the recycle can.

I'm also just not disciplined enough to keep close track of such things.

beatledog7
April 4, 2012, 05:05 PM
Tiny amount of flare makes starting bullets a breeze.

Seat a set of bullets by first trying one on a sized but unflared case to see if it will balance there without being held. If it will, it will most likely seat without flare. If not, flare that case the tiniest bit and try again. Keep doing this until the bullet will just rest in the case mouth without falling off level.

Whatever that flare is, it's enough. It will vary by bullet and sometimes by brand of brass.

It's quite likely that when you seat the bullet (depth will vary by bullet and your barrel), it will chamber without any intentional taper crimp being applied. The shaft of the bullet being pressed into the case mouth opens the case as much as or more than the flare you applied; the net effect is the flare is gone.

eldon519
April 4, 2012, 06:30 PM
I use mixed range brass 9mm and don't trim it. Some cases consequently are longer than others and the shorter ones sometimes do not get belled enough. On the ones that do not always get belled enough, sometimes they will cut thin slivers off the base edge of jacketed rounds. Consequently, I gave the die a little extra to bell more aggressively for my next batch. It may shorten brass life, but frankly I lose them and do not keep track of how many times straight-walled semiautomatic pistol cases have been loaded anyway.

Walkalong
April 4, 2012, 06:35 PM
9MM headspaces on the case moth. Over chamfering and an aggressive crimp could easily give problems. Many people do not bell when using jacketed bullets, and get away with it. I bell them slightly for jacketed, and more for lead. I would not deburr or chamfer 9MM cases that have not been trimmed (And I am not going to trim one), even if I did not want to bell them.

Your choice, but the expander does two things. It brings the case ID up to a point where seating won't be as hard, which will be more consistent, and it bells slightly to aid seating.

I would bell them slightly, but would not deburr or chamfer them.

engineermike
April 4, 2012, 07:50 PM
Hard to get the same bell on the cases that are not the same length.

gamestalker
April 4, 2012, 07:53 PM
Yes, from the inside. Just a very light touch in the drill at low speed using a Lee stud and shell plate, or do it by hand. Using a Wilson ream and chamfer it only takes a second or two per case doing it by hand. I personally feel this increases neck tension, and more consistent fps.

1SOW
April 5, 2012, 03:04 AM
rcmodel & Walkalong +2

For 9mm pistol, set up for a very small bell on the shorter cases and tapercrimp back to .378-ish". The longest cases might end up .377-ish" . With proper case sizing/neck tension the bullet is held very securely either way.

JMO: Because the seating depth does change a skosh with different case-lengths, chrono results 'may' show a slightly higher SD. For me it's insignificant, and NOT worth trimming 9mm cases. Any group 'flyers' I have is not due to case length variations.

engineermike
April 5, 2012, 10:33 AM
Mine seem to have a larger variance. I am finding 9mm cases from .736 to .753 at my pistol range. My sizing die leaves the case mouth around .372 and have found some of the outside measurements "After 115 g bullet seated" to be .375 and this is with out any crimp. If I were crimping to .375 some would say that I have over crimped the case and should watch out for this would surely increase the pressures and might be dangerous. Although nothing blew up but the cases that have the smaller outside measurement do have more recoil and it did effect the accuracy of the FMJ round nosed bullets I was shooting.

So belling the case mouth to around .378 or .379 and taper crimping the case mouth to around .377 seems to give me a better load. I know this tread is about case trimming but if one were to set his die using the longer case then the shorter case would have less bell and the outside measurement of the case could be smaller than .377. Not saying you need to trim the cases but maybe you may want to load cases that are closer to the same length.

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