Calculating the bell

Roland Thunder · February 2, 2012, 01:46 PM

I saw a video yesterday in which the author calculated the bell by using his calipers to measure the circumference of the case mouth before sizing and then repetitively adjusting the flare and measuring the circumference again until the new circumference is .020 greater than the original one.

Anybody use this method or have another one?

FrankenMauser · February 2, 2012, 02:30 PM

Standard expander dies:
Insert case in shellholder.
Run into die.
Adjust die until it looks to be "just enough" to cleanly seat the bullet I'm using.
Done.

Lyman M dies:
Insert case in shellholder.
Run into die.
Adjust die until I feel the top of the second step.
Back off just far enough to accommodate the longest case in the group.
Done.

Roland Thunder · February 2, 2012, 02:38 PM

yep, that's the way I do it too

g.willikers · February 2, 2012, 04:42 PM

Isn't there some differences in case thickness, from the various brass manufacturers, and does it possibly cause a problem with this method?

amathis · February 2, 2012, 05:06 PM

Wow! That seems a bit anal for practice round but I wonder how much it effects accuracy rounds. If it shows a marked improvement, perhaps its worth a try.

I eyeball it. Its not scientific but it works.

Ideal Tool · February 2, 2012, 05:22 PM

Calculate?..measure outside case dia.? Why not just adjust M Die expander plug downward until bullet base just enters case?

BigJimP · February 2, 2012, 05:36 PM

I use a less scientific method....

( if the bullet doesn't tip over easily in station 4 ....when I set the bullet on the case....or when I activate the press arm - its belled enough). If it tends to tip over...I bell it a little more...

serf 'rett · February 2, 2012, 05:44 PM

Adjust as needed for bullet to start.

jepp2 · February 2, 2012, 08:06 PM

Quote:

until the new circumference is .020 greater than the original one.

The standard guidance by Dillon is 0.020" flare, but that it to get the powder measure to operate properly.

That is way more flare than I use. For jacketed rounds using a Dillon measure I flare 0.001 to 0.002" flare. But I run my measure differently than the current set up. I do not use the fail safe rod and I use springs (the way they used to sell them). For lead I flare about 0.003" to avoid shaving.

When I load for 357 Sig I don't flare at all.

To me a flare of 0.020" is going to shorten case life due to splits. But that's just me.

When I use a Lyman M die, I follow the manufacturers recommendation and only let the step enter the case 1/16". That is sufficient to get the bullet to stand up straight for seating.

I do measure the flare because I like to minimize the amount I work the neck. I am not saying that is necessary, but that is just the way I do it.

higgite · February 2, 2012, 08:13 PM

Quote:

I use a less scientific method....

( if the bullet doesn't tip over easily in station 4 ....when I set the bullet on the case....or when I activate the press arm - its belled enough). If it tends to tip over...I bell it a little more...

What he said.

wncchester · February 2, 2012, 09:05 PM

"Adjust as needed for bullet to start. "

There you go, that works fine and no caliper is needed.

dickttx · February 2, 2012, 10:26 PM

Another +1 for BigJimP.
I increased my loading speed considerably on my LCT when I put a little more flare in the case mouth and quit fumbling around with the bullet.
What if it does shorten the case life. I have never worn out or split a 9mm or 45 ACP case, and I always come home with more than I went with.
I load all of mine with the same brand of brass in plastic boxes of 100. However, I don't make any adjustments from one brand to the next. I currently have 100 round boxes of Win, FC, R-P, Starline, PMC, and 1961/1971 mixed GI. They all shoot the same.

1SOW · February 2, 2012, 11:49 PM

BigJimP, exactly.
Don't "over-engineer" a simple process.

You want the "minimum" bell that allows you to set the bullet on the case mouth and stay there until the seater die has done it's job.

Like reloading: Start low and slowly work up until your happy.

FrankenMauser · February 3, 2012, 12:08 AM

Quote:

Isn't there some differences in case thickness, from the various brass manufacturers, and does it possibly cause a problem with this method?

If you're working with a single lot of brass from a single manufacturer, it isn't an issue.

You're not mixing brass are you? The safety Nazis will come get you.

Roland Thunder · February 3, 2012, 11:43 AM

Quote:

Wow! That seems a bit anal for practice round but I wonder how much it effects accuracy rounds. If it shows a marked improvement, perhaps its worth a try.

I eyeball it. Its not scientific but it works.

This is the way I've always done it. I figure the guy that made the video must wear a pocket protector.

amathis · February 3, 2012, 02:08 PM

Quote:

I figure the guy that made the video must wear a pocket protector.

When I was in college I worked in the IT department. (I know nerd alert. . . . .) We had 3-4 guys who always had pocket protectors. I always told them that was the only protection they would ever need. . . . .

I am seriously debating doing an experiment along the lines of seeing how many uses I can get out of a piece of brass belled to 0.002 compared to eyeballing it. I'd also be really curious to see if the accuracy is any different. I'll let you all know if I attempt this and then post back with results if I do.

Crashbox · February 4, 2012, 12:41 PM

I set the belling for minimal bell- since I have used jacketed bullets from day one I don't mind holding the bullet while on the upstroke to seat it. Sometimes the fingers get squeezed but that's life.

I should mention I'm only talking about my .357 Magnum cases; if/when I start to load for my .405 Chestwhipper or 6.5 Roberts I might change my approach.

m&p45acp10+1 · February 4, 2012, 12:51 PM

When using cast bullets I set it where I do not get lead shavings. If I wear cases out faster I am ok with that. I can pick up more at the range. I have never had a .45 acp, or .38 spcl split yet. With .41 mag I have had a few split at the case mouth after more firings than I can count. I got my money's worth out of that brass long ago.

Accuracy has not suffered any that I can tell. POA, and POI match that is all I care about. From handguns they shoot more acurately than I can milk them for anyway.

February 2, 2012, 01:46 PM	#1
Roland Thunder Senior Member Join Date: December 29, 2010 Location: Gwinnett County Georgia Posts: 1,136	Calculating the bell I saw a video yesterday in which the author calculated the bell by using his calipers to measure the circumference of the case mouth before sizing and then repetitively adjusting the flare and measuring the circumference again until the new circumference is .020 greater than the original one. Anybody use this method or have another one? __________________ Do not follow where the path may lead, go, instead where there is no path and leave a trail - Ralph Waldo Emerson

February 2, 2012, 02:30 PM	#2
FrankenMauser Senior Member Join Date: August 25, 2008 Location: In the valley above the plain Posts: 13,424	Standard expander dies: Insert case in shellholder. Run into die. Adjust die until it looks to be "just enough" to cleanly seat the bullet I'm using. Done. Lyman M dies: Insert case in shellholder. Run into die. Adjust die until I feel the top of the second step. Back off just far enough to accommodate the longest case in the group. Done. __________________ Don't even try it. It's even worse than the internet would lead you to believe.

February 2, 2012, 02:38 PM	#3
Roland Thunder Senior Member Join Date: December 29, 2010 Location: Gwinnett County Georgia Posts: 1,136	yep, that's the way I do it too __________________ Do not follow where the path may lead, go, instead where there is no path and leave a trail - Ralph Waldo Emerson

February 2, 2012, 04:42 PM	#4
g.willikers Senior Member Join Date: September 28, 2008 Posts: 10,442	Isn't there some differences in case thickness, from the various brass manufacturers, and does it possibly cause a problem with this method? __________________ Walt Kelly, alias Pogo, sez: “Don't take life so serious, son, it ain't nohow permanent.”

February 2, 2012, 05:44 PM	#8
serf 'rett Senior Member Join Date: June 25, 2009 Location: Stuttgart, AR Posts: 1,569	Adjust as needed for bullet to start. __________________ A lack of planning on your part does not necessarily constitute an emergency on my part.

February 2, 2012, 05:06 PM	#5
amathis Senior Member Join Date: March 20, 2009 Location: Champlain Valley, Vermont Posts: 161	Wow! That seems a bit anal for practice round but I wonder how much it effects accuracy rounds. If it shows a marked improvement, perhaps its worth a try. I eyeball it. Its not scientific but it works.

February 2, 2012, 05:22 PM	#6
Ideal Tool Junior member Join Date: October 6, 2010 Location: Michigan Posts: 1,080	Calculate?..measure outside case dia.? Why not just adjust M Die expander plug downward until bullet base just enters case?

February 2, 2012, 05:36 PM	#7
BigJimP Senior Member Join Date: February 23, 2005 Posts: 13,195	I use a less scientific method.... ( if the bullet doesn't tip over easily in station 4 ....when I set the bullet on the case....or when I activate the press arm - its belled enough). If it tends to tip over...I bell it a little more...

February 2, 2012, 09:05 PM	#11
wncchester Senior Member Join Date: December 1, 2002 Posts: 2,832	"Adjust as needed for bullet to start. " There you go, that works fine and no caliper is needed.

February 2, 2012, 10:26 PM	#12
dickttx Senior Member Join Date: May 29, 2011 Location: Fort Worth Posts: 500	Another +1 for BigJimP. I increased my loading speed considerably on my LCT when I put a little more flare in the case mouth and quit fumbling around with the bullet. What if it does shorten the case life. I have never worn out or split a 9mm or 45 ACP case, and I always come home with more than I went with. I load all of mine with the same brand of brass in plastic boxes of 100. However, I don't make any adjustments from one brand to the next. I currently have 100 round boxes of Win, FC, R-P, Starline, PMC, and 1961/1971 mixed GI. They all shoot the same. __________________ Education teaches you the rules, experience teaches you the exceptions (Plagiarized from Claude Clay)

February 2, 2012, 11:49 PM	#13
1SOW Senior Member Join Date: December 2, 2007 Location: South TX Posts: 269	BigJimP, exactly. Don't "over-engineer" a simple process. You want the "minimum" bell that allows you to set the bullet on the case mouth and stay there until the seater die has done it's job. Like reloading: Start low and slowly work up until your happy.

February 4, 2012, 12:41 PM	#17
Crashbox Senior Member Join Date: November 3, 2009 Location: Lynden, Washington Posts: 199	I set the belling for minimal bell- since I have used jacketed bullets from day one I don't mind holding the bullet while on the upstroke to seat it. Sometimes the fingers get squeezed but that's life. I should mention I'm only talking about my .357 Magnum cases; if/when I start to load for my .405 Chestwhipper or 6.5 Roberts I might change my approach. __________________ Four Rugers, three SIG Sauers, assorted rifles. NRA, GOA and SAF Life Member.

February 4, 2012, 12:51 PM	#18
m&p45acp10+1 Senior Member Join Date: May 3, 2009 Location: Central Texas Posts: 3,930	When using cast bullets I set it where I do not get lead shavings. If I wear cases out faster I am ok with that. I can pick up more at the range. I have never had a .45 acp, or .38 spcl split yet. With .41 mag I have had a few split at the case mouth after more firings than I can count. I got my money's worth out of that brass long ago. Accuracy has not suffered any that I can tell. POA, and POI match that is all I care about. From handguns they shoot more acurately than I can milk them for anyway. __________________ No matter how many times you do it and nothing happens it only takes something going wrong one time to kill you.