dillon 750 (re)setup help plz

[davsco]

So i took all the dies out and cleaned them and am switching from 9mm 124 to a run of rmr fjm 135s (.355).  Redding sizing and bullet seating dies; dillon powder die/expander.

 

The issue is I am getting bulging when seating.  I dropped the powder funnel to further bell the case, but getting the belling further down also gets it pretty wide.  So wide that it seems the case mouth is hitting the seating die.

 

Would appreciate input on if I am belling too much or too little and/or what i need to do at powder and seating stages to get a smoother-looking case.  I am trying for a COAL of 1.125.  As you can see from 3rd pic the belling i have currently gives an OAL of 1.214, so at seating the bullet is still being forced in/down some.  Of course any other input is welcome also.

 

You prob also notice that the seating die is leaving a ring on the bullet, around the nose and down from the tip just a little.  Probably just cosmetic but input welcome on that also.

 

thanks!!

[Edwards30]

You are certainly belling too much.  I don't have an exact measurement for you, but I know Dillon references one on their YT video regarding die setup on Dillon 750.

I would start with watching the video, I went ahead and found it for you: 

 

[davsco]

neat video, thanks!  i will go thru setup start to finish again.

[Farmer]

Yes way too much bell. Also using a flat nose punch on your seating die can help. Your die set should have came with one. If that is the flat punch causing the ring you may be able to polish the punch a bit to get it to fit the bullet better. I’ve had some that need a fair amount removed to fit properly. Some push more on the ogive and not the nose causing alignment problems. 

Edited May 16, 2022 by Farmer

[VortecMAX]

Just a guess, but the bulging could be due to the bullet tipping before being forced into the case.  I agree with the others that say you are belling too much.  Belling that much really works the brass and would shorten the life.  Is your "bulging" more prominent on one side?  If so, that is a bullet misalignment during seating.

 

Mike

 

[VortecMAX]

I see "bulging" in one of your photos, but it looks uniform all around the base of the bullet in the case.  That "wasp waist" look is perfectly normal.  I am not sure if that is the "bulge" you were referring to.

 

Mike

 

[davsco]

51 minutes ago, VortecMAX said:

I see "bulging" in one of your photos, but it looks uniform all around the base of the bullet in the case.  That "wasp waist" look is perfectly normal.  I am not sure if that is the "bulge" you were referring to.

 

yes, bulging but seems uniform.

 

so now that i've gone thru and re-set all the dies and belling, i'm still getting very inconsistent seating.  i'm going for 1.125 but am getting a range from like 1.115 to 1.144.  i can never get that shellplate totally wobble-free without it binding but it's not wobbling enough for that variance.  the redding seating die is leaving a ring just below the top of the bullet.  thinking the ring itself isn't a big problem but perhaps not consistent contact.  i just ordered a dillon seating die that has a flat and conical side and maybe the flat option will seat more consistently.  again, open to suggestions.  i def wasn't getting that large a variance with the 124 fmj's.

[davsco]

2 hours ago, Farmer said:

Yes way too much bell.  

i started off with a 'normal' bell but was getting a lot of bulging.  guessing the increased friction to fully seat the bullet was leading to inconsistent seating depth/OAL issues.  seemed to get better with a deeper albeit wider bell but i can see how that weakens the brass.

[smfort]

I agree with davsco, "way too much bell".  

[ddc]

When belling for RMR jacketed bullets you shouldn't have to go terribly wide.

They are after all jacketed and have enough curvature at the base to help out with insertion/seating.

Depending upon the die you are using perhaps .381 "ish" should work maybe another .001 or so.

But that megaphone is so far over it's not funny.

 

Belling/flaring dies can be a bit of a quandary because what works for one seems to cause problems for others.

I don't think it has to be that complicated but if it wasn't I guess there wouldn't be that many threads on the subject.

 

Something to consider is an aftermarket powder through die such as available from Mr. Bulletfeeder.

There are several options in this area and a number of threads in this forum on the subject.

Highly recommended over the factory Dillon offering.

Edited May 16, 2022 by ddc

[davsco]

58 minutes ago, ddc said:

But that megaphone is so far over it's not funny.

 

Highly recommended over the factory Dillon offering.

i was basically playing around and seeing if a super wide bell and the reduced seating friction would perhaps give lower OAL variances, but it didn't seem to help...

 

I'll look but what are the pro's of the Mr Bulletfeeder?

[Edwards30]

I may have missed this but what is your seating/crimping setup?  Are you doing it all in one station?  

I long ago switched to separate seating and crimping dies to eliminate the issues that come along with that.  

To answer another question you had, the Mr Bulletfeeder powder die has a lip on it that bells the case differently.  It's on my purchase list as I have some bullets tip over on my 750.

[ysrracer]

7 hours ago, smfort said:

I agree with davsco, "way too much bell".  

 

Way, way, way too much bell.

[Farmer]

I don’t know if you have room for a M-type expander die but I find it does a much better job without overworking the brass. Lyman started with them but other companies have followed with the design. The problem with the “funnel” type expander is that the bullet doesn’t sit square in the brass. With an M die it expands with a square bottom so the bullet sits flat and square with the brass. 

Edited May 17, 2022 by Farmer

[boatdoc173]

did you  use the flat tip nose for the seating die?  it is reversible. one side is used to seat round nosed  bullets, the othe r is for flat tipped bullets

 

the slight bulge seen in the last pic seems to  be just how the  case molds to the bullet you are using. nothing abnormal there

[davsco]

8 hours ago, Edwards30 said:

I may have missed this but what is your seating/crimping setup?  Are you doing it all in one station?  
 

yes all in one station as the redding die set didn't come with a crimping die.  i played around with the die depth and seating stem depth to try not to crimp before seating but that's not saying i got it right.  i just ordered a dillon seating die and will try both sides of the stem to see what works best, and also ordered a lee crimp die so that step will be separate now.

[davsco]

6 hours ago, Farmer said:

I don’t know if you have room for a M-type expander die 

i'm using a dillon 750.  first stage is sizing, 2nd is powder, then an unused spot, then seating and then crimp.  not aware of how to expand/bell before the dillon powder stage, doesn't seem that i can shift that one spot clockwise?

[davsco]

1 hour ago, boatdoc173 said:

did you  use the flat tip nose for the seating die?  it is reversible. one side is used to seat round nosed  bullets, the othe r is for flat tipped bullets

 

the slight bulge seen in the last pic seems to  be just how the  case molds to the bullet you are using. nothing abnormal there

the redding i'm using isn't reversible.  just ordered the dillon which is reversible and i will see which side works best (lowest coal variance) for these rmr 135g bullets.

[ddc]

55 minutes ago, davsco said:

i'm using a dillon 750.  first stage is sizing, 2nd is powder, then an unused spot, then seating and then crimp.  not aware of how to expand/bell before the dillon powder stage, doesn't seem that i can shift that one spot clockwise?

 

The only way that I am aware of is you can theoretically move the powder station clockwise one position.

However that makes the factory positive return linkage unusable.

That means that you would have to use the original Dillon "return spring" method of operating the powder measure.

 

I have not done that but have seen references to that modification.

 

But...

 

I don't think that should be necessary in any way, shape or form.

 

The vast majority of loaders use the 650/750 as designed.

 

Tuning the powder measure for the proper bell is just not the most straightforward thing to do for a newer reloader.

 

You will get there.

 

[Edwards30]

2 hours ago, davsco said:

yes all in one station as the redding die set didn't come with a crimping die.  i played around with the die depth and seating stem depth to try not to crimp before seating but that's not saying i got it right.  i just ordered a dillon seating die and will try both sides of the stem to see what works best, and also ordered a lee crimp die so that step will be separate now.

I am just using a cheap RCBS seating/crimp die and I screwed the seating stem all the way down so it is essentially a seating only die as the crimp part doesn't contact.
I am using the Lee FCD in the last station to keep the cases uniform.

[davsco]

ok i will back off the WAAAAAAAAYYYYY too big belling and see if the seating stem profiles on the dillon and lee seating dies work better with the 135's.  crimping in a separate step prob won't hurt either.  thanks for all your input!

[Farmer]

7 hours ago, davsco said:

i'm using a dillon 750.  first stage is sizing, 2nd is powder, then an unused spot, then seating and then crimp.  not aware of how to expand/bell before the dillon powder stage, doesn't seem that i can shift that one spot clockwise?

Yeah that’s a problem. Guess a guy needs to work on a decent expander for the Dillon. I hear a lot on here about the MBF powder funnel but I don’t know how it expands. 

[Farmer]

2 minutes ago, davsco said:

ok i will back off the WAAAAAAAAYYYYY too big belling and see if the seating stem profiles on the dillon and lee seating dies work better with the 135's.  crimping in a separate step prob won't hurt either.  thanks for all your input!

Should be just enough for the bullet to clear the mouth. If your getting bulging on one side it’s more than likely your seating stem giving the problem. 

[VortecMAX]

Do the "bulged" cases fit into a case gauge?  Or do they drop freely into the chamber of your barrel?  If they do, then there really is not an issue.  If they don't, I would now suspect (given new information about seating/crimping in same station), that you are overcrimping, causing the case to buckle as the bullet seats.  I seat and crimp in two separate stations and highly suggest you try doing it that way if you can.

 

Mike

 

[davsco]

the bulging was really all the way around.  they do fit in the hundo case gauge but just didn't look 'right.'  with the single die for seating and crimping i prob don't have it positioned good.  at least for this 135 bullet i will use separate dies for seating and crimping.  i was using the same toolhead & dies that have been working great for 124's but clearly the different bullet profile is calling for something different.  with new dies inbound that hopefully have profiles that better match the 135g, and seating and crimping separately, i'm hopeful this problem (bulging and inconsistent COAL) will go away.