Inconsistent belling - Dillon 550b

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MoreIsLess

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I seem to be having a problem with the powder die not belling the cases consistently. It seems to be about 1 out of every 5 or 6 are not belled sufficiently and I end of with the OAL being too long. It seems to be dispensing powder correctly even when not belling the case. The die is sufficiently tight on the toolhead and the screws that hold the powder dispenser to the die are tight as well.

Any idea what would cause this?
 
What caliber are you loading?? Pistol, revolver? You may need to check the OAL of the case after you size and before you bell them. They may need to be trimmed?

rcmodel said it better down below..
 
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Inconstant belling should not cause OAL variation, unless you are loading lead bullets and shaving lead when you seat them.

If that is the problem, inconstant case length is the problem.
And only trimming them all to the same length will fix it.

rc
 
I'm loading 45 acp. Same cases I was using with ny Lee Turret press and never had any belling inconsistencies. I've never had to trim 45 cases. I can usually see by looking that the bell is missing after going thru the powder die. When I see this , I set a bullet on there and it almost tips over while the ones where I can see the bell, when I set a bullet on it, it sits perfecetly in the case. So, there definitely is a belling problem. Additionally, when I measure the ones that don't bell properly, the OAL is consistently longer than the ones that do bell OK.
 
It sounds like either some cases are shorter (or longer) than others, which would account for inconsistent belling, or you aren't always pulling the handle all the way down.
 
All instances of inconsistent belling I've encountered have been due to case length differences.

You might also measure several cases after sizing, pick the longest and the shortest then load these to see if the short one isn't getting belled sufficiently.

MAKE SURE THAT YOU DON'T DOUBLE CHARGE A CASE WHILE CHECKING BELLING OPERATION

One other thing you might try -- make sure the shell plate is is not loose. A wobbly shell plate can cause problems.

Remove the shell plate, clean it and the shell plate platform thoroughly (make sure you don't lose the index ball). Make sure all screws on the platform are tight. Install the shell plate and tighten fully, then back off a little at a time until you can turn it thru the entire cycle without binding.
 
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I agree with the others;
Make sure your cases are all about the same length
Make sure the cap screws on the measure are tight
and one more thing: Sometimes I notice if you charge a case, with it being the only case in the shellplate, it doesnt bell quite as much as when you have a full shellplate of cases. I think it is due to a slight rocking of the diehead, due to no other sizing/seating/crimping applying opposing forces to the diehead.
Good luck
 
Having run two Dillon 550B's for many years and not ever having this problem and assuming all your cases have the same OAL, I would also suspect your powder measure is not tightly adjusted and is rotating slightly on each operation. Check it out for tightness and if that's not the case, call Dillon Tech Service. They have seen and solved all manner of problems.
 
I had this problem too. I figured out that my bell was almost right but a tad bit small for a small portion of the range pickups I use. I adjusted the die for a bit more bell and haven't had any more problems.
 
We recommend flaring case to a minimum of .010-.020" larger than the sized, unflared case mouth measures. This ensures sufficient flaring within a typical handgun case length variation.
 
Belling 45acp

We recommend flaring case to a minimum of .010-.020" larger than the sized, unflared case mouth measures. This ensures sufficient flaring within a typical handgun case length variation.
Brass life will be short belling to .020" IMO. My test shows a sized body of .467" to .468 RCBS die. Belling of short brass @ .888" to .4715" = a bell of .0045" When a case that is .898" has the same Dillon expander setting, the bell measures .4765" to .477" or a bell of .010" I have to wonder if a bell of .020" would even enter the seating die? :scrutiny: It enters the seating die. I had to try it.
 
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