How much "Bell" on case mouth?

[Charlie Horse]

No stupid questions, right? Have you ever measured the amount of bell you put on the case mouth when you are setting up your die? I try to shoot for about .006", but sometimes go around .010" just because the dies are so touchy.
For example, with 9mm, the OD at the end of a loaded case is .380". I try to bell my cases between .386" and .390".
Or do you just do it by sight/touch/feel?

[Winger Ed.]

I've never measured it, but I flare until a boolit will just stand straight up in the case,
and go into the seater die without shaving Lead.

If you have issues with different case lengths, the Lee 'powder through the expand' die might be a good option for ya.

[Mk42gunner]

I'm fairly sure I have measured once or twice, but I can't remember for sure.

What I tend to do is adjust the expander with the projectile nearby and go until the base sits down in the neck about half the thickness of a dime. No chance then of shaving lead.

Robert

[jonp]

What Winger Ed said. Never measured.

[RickinTN]

Only minimum. Enough to get the gas check or base of a plain based bullet about halfway in before meeting resistance. I visited a friend once while he was loading 38 specials. His Dillon loader was set up to flare the cases so much it looked like a cigar that had a load go off. I asked him why so much and he stated he wanted to make sure he had enough flare. I assured him he did. I asked about his case life and he said brass cases split after about three loadings and he told me nickel cases are no good, they split the first loading.
Rick

[Char-Gar]

I've never measured it, but I flare until a boolit will just stand straight up in the case
and go into the seater die without shaving Lead.

This is how I do it as well.

[georgerkahn]

I've never measured it, but I flare until a boolit will just stand straight up in the case,
and go into the seater die without shaving Lead.

If you have issues with different case lengths, the Lee 'powder through the expand' die might be a good option for ya.

I am ever in concert with this post! PLUS, added, my belling is the barest minimal amount necessary to enable its going " into the seater die without shaving Lead"

[NSB]

I’ve been loading for over fifty years, and I shoot a lot. I’ve NEVER measured it and I flair to the barest minimum amount possible. I actually hold the bullet until the case goes into the die. Probably why I’m still shooting nickel cases I bought decades ago ( I buy in large bulk quantities so I have no idea how many loads I’ve gotten, but it’s a lot).

[405grain]

I flare the case mouths until half the gas check will enter the case. On every cast loading, pistol or rifle, I make seating and crimping two separate operations.

[megasupermagnum]

In handguns, most of the time I just flare as much as I can, and still fit it into the seating die.

[Charlie Horse]

I flare the case mouths until half the gas check will enter the case. On every cast loading, pistol or rifle, I make seating and crimping two separate operations.

This is about what I do.

Calipers are probably my most used tool. I habitually measure everything that comes across my loading bench. Seems .006" over loaded neck outside diameter is a good amount of flair for all my lead boolit loads. I was just wondering what other people do. .006 will allow about half of a gas check height to seat in the case mouth.
I'm processing about 1000 9mm cases. They've been washed, dried, and sized. (I don't tumble.) Now I'm flaring. All on a single-stage press.
When I'm ready to go shooting I'll assemble a box the night before. I'll do two boxes if I'm going to a plate shoot. I never load a bunch of ammo in advance. Never have. But I do process cases.

[BK7saum]

I don't flare the case mouth. I use M-dies or NOE expanders. The step is about 0.001-0.002" over bullet diameter to a depth of about ½ of the gas check.

I never cared for the varying flare depending on the varying case length. I always tried for minmal flare to prolong case life and invariably would end up shaving lead from a short, unflared case.

[uscra112]

i don't flare the case mouth. I use m-dies or noe expanders. The step is about 0.001-0.002" over bullet diameter to a depth of about ½ of the gas check.

I never cared for the varying flare depending on the varying case length. I always tried for minmal flare to prolong case life and invariably would end up shaving lead from a short, unflared case.

^^^^^this^^^^^

[megasupermagnum]

I don't flare the case mouth. I use M-dies or NOE expanders. The step is about 0.001-0.002" over bullet diameter to a depth of about ½ of the gas check.

I never cared for the varying flare depending on the varying case length. I always tried for minmal flare to prolong case life and invariably would end up shaving lead from a short, unflared case.

I use a lot of NOE plugs. .001" over shaves a bullet every single time unless you chamfer the case mouth. .002" isn't much better. Any bigger, and you have no neck tension. I now always follow with the Lee expander after I use NOE plugs. It's the only way to be sure you aren't shaving lead.

[dverna]

Another guy who does not measure. Enough to get the bullet started without issues.

[BK7saum]

I use a lot of NOE plugs. .001" over shaves a bullet every single time unless you chamfer the case mouth. .002" isn't much better. Any bigger, and you have no neck tension. I now always follow with the Lee expander after I use NOE plugs. It's the only way to be sure you aren't shaving lead.

My mistake for not taking rhe time to be more clear. I did not mean to say the flare step was 0.001-0.002 over bullet diameter. What I meant was the ID of the case mouth was 0.001-0.002 over bullet diameter. I usually use an expander bullet diameter or about a half thousandth under, which puts the actual ID about 0.001-0.002" over bullet diameter. The flare step is actually 0.003-0.004 over bullet diameter, but with springback allows bullet to seat without shaving.

I have never had a problem with not enough neck tension.

[GregLaROCHE]

I’ve only had good results with the NOE plug system. Are you sure you are using the right size plug and not pushing it too far in? It’s supposed give two expansions. One that gives the right tension and a second slightly larger, just at the top of the neck to help get the boolit started.

[pworley1]

I do it Winger Ed's way.

[243winxb]

.005" larger then case body. Just buy good dies. RCBS 9MM- "M" Die Expander. https://www.thehighroad.org/index.php?media/rcbs-expander-m-type-9mm-strange-black-coating.3604/full

[Rapier]

I use taper crimp dies, so bell to just set a bullet base inside the case, then seat, then taper crimp until the case is straight only.

[45DUDE]

I've never measured it, but I flare until a boolit will just stand straight up in the case,
and go into the seater die without shaving Lead.

If you have issues with different case lengths, the Lee 'powder through the expand' die might be a good option for ya. I am with you. My cases last a very long time. 45acp and 38 special maybe 40 or more reloads. I just do it enough not to shave lead and a tweak more since the 80's.

[Bazoo]

In handguns, most of the time I just flare as much as I can, and still fit it into the seating die.

I pretty much do this. I flare until it scrapes the inside of the seat die a bit, then back it off just enough that it doesn’t. That is, if I’m using a flare/belling die and not an M style.

[John Boy]

Rule of Thumb … width of case mouth so 1/2 of the bullet base can be seated in the case

[uscra112]

Cast bullets do not need much if any "neck tension". Loading 'em like J-words just distorts 'em. If you need retention against revolver recoil, that's what a firm roll crimp is for. That's tough enough on your brass without flaring it every time.

[Bazoo]

In 44 special have found I can use .002 neck tension with both 50/50 ww/PB and straight WW alloy, but if I try .003, I get base swaging. So for atleast with those alloys, .002 is the max. I haven’t tried harder alloys.

[megasupermagnum]

My mistake for not taking rhe time to be more clear. I did not mean to say the flare step was 0.001-0.002 over bullet diameter. What I meant was the ID of the case mouth was 0.001-0.002 over bullet diameter. I usually use an expander bullet diameter or about a half thousandth under, which puts the actual ID about 0.001-0.002" over bullet diameter. The flare step is actually 0.003-0.004 over bullet diameter, but with springback allows bullet to seat without shaving.

I have never had a problem with not enough neck tension.

Ok, that makes a lot more sense. There are a number of problems with the NOE plugs, and yes, I do have a lot of experience with them. I modify them on a lathe to make them more useable, but they aren't perfect. I personally feel the step NOE just isn't good. It could be acceptable if it were bigger. In your case, you are getting adequate expansion. In most instances, having that step only .004" over the body diameter is far from enough. Anyone who claims to use one that is .001" or .002" under bullet dimeter (meaning the step is .003" or .002" over bullet diameter), and not shaving lead, is not paying attention. They are definitely shaving lead unless they are chamfering the case mouth. I don't want to chamfer my case mouths when a flare works without it. .010" over would be more realistic. I personally don't see any reason to use anything except a flare. The pictured below "modified" is how the NOE plugs should come if they really wanted to make a superior product. There's no reason to have so much surface on them, and there's no reason not to flare. The surface issue especially sucks. I've been reloading for quite a while, and never stuck a case in a FL sizing die. In the few years I've used the NOE plugs, I've ripped the rim off a number of cases. There's no reason not to have them drilled for powder through either. I'm sure they work for you, which is great, but for a lot of us, they aren't perfect. I use them when I have to, but they are just another tool. If they were modified, they could become the perfect solution.

https://i.ibb.co/X5yTf13/noeplug.jpg (https://ibb.co/X5yTf13)

[Glwenzl]

I use NOE expanders… Tonight I was seating some light load 38 Special using mixed brass and old Herters WCs that are like half jacketed (a first for me). Oddly the bullets set into the expanded step for the bullet, then after seating the bullet (no lead shaving) I decided to check them in the cylinder of my GP100. To my surprise, all dropped in except for two that went most of the way in. I gave them both a little pressure and think they may have went in but decided to check them tomorrow to see if they just need a little more crimp.

At any rate, the old flare will get the job done but the NOE sure does a fine job at providing Buck tension and expanding for the bullet.

[Glwenzl]

My main actually only issue with NOE is that on one instance, the .316” plug was catching the mouth lip on the 7.62x54R brass folding it over. I had to go slow on those to ensure the brass was centered in the plug. While that is a pretty over sized bullet I’m seating, I think a little more taper on the bottom of the plug would be beneficial

[Bazoo]

I’ve used the NOE 454x450 with .452 bullets in 45 auto, and I’ve not experienced lead shavings. I load carefully though to avoid it. No chamfer of the case mouth.

I have used the same .002 difference in 44 special with no shaving, but with chamfering. However the length isn’t sufficient for my bullets, barely expanding the length of the driving bands with none to spare.

[uscra112]

Anyone who claims to use one that is .001" or .002" under bullet dimeter (meaning the step is .003" or .002" over bullet diameter), and not shaving lead, is not paying attention.


If my seater die were shaving lead when the case mouth has those dimensions, I'd ask myself whether my seater stem was not concentric or didn't fit the bullet nose correctly.

And how in blazes can the expander have anything to do with sticking cases in the sizer die? It gets used after the case has gone through the sizing operation.

[popper]

sight/touch/feel. I don't trim cases so they are all different. Using the Lee flare tool in the SS press, I set it to touch the mouth, then give it a hard tap (estimate how far the handle needs to move). And keep it handy in the Lee hand press when seating so if there is one a bit small, pop it again. If it doesn't set 1/2 GC depth, enlarge (estimate for PB). For thin necks like 30/30 I use a single twist of needle nose pliers. If not right, another twist does the job. I don't have a progressive press so no problem.

[John Boy]

Take this to the bank, you’ll learn quick enough when you over bell a case when you put them in the FL sizing die and the die won’t close … one recycle scrap case

[atr]

just enough to accept the gas check

[uscra112]

Consider the case of the .38 Special. The case mouth gets flared, then crimped, then flared, then crimped, over and over again. Now think about a narrow band of metal, say, .010 wide, right at the mouth. It gets work-hardened twice in each cycle, leading to cracking. If you don't flare, that band gets worked less. The conclusion is obvious.