stop on Dillon 550x

dahermit · October 8, 2020, 11:21 AM

Question: what on a Dillon 550x press makes the positive stop on the priming stroke. Go to your 550x and push the handle back with no case in the shell plate and tell me what stops the stroke. I think I know, just want concurrence.

**Unclenick** · October 8, 2020, 11:36 AM

Shell plate platform meets the primer slide on my 550B.

dahermit · October 8, 2020, 12:22 PM

Quote:

Originally Posted by Unclenick

Shell plate platform meets the primer slide on my 550B.

How have you determined that...have you used strips of paper to determine the pinch points? Has the point where the shell plate platform stops/touches the primer slide made an indentation mark in the primer slide?

FrankenMauser · October 8, 2020, 08:06 PM

I think it's supposed to be the primer slide. But I had my 550B mounted directly to a bench. The stop was the handle hitting the bench.

Kevin Rohrer · October 8, 2020, 08:40 PM

On mine, it was either when the handle hit the bench top edge, or when the press shaft buttons-out at the top of the stroke.

rodfac · October 9, 2020, 07:11 AM

Quote:

Shell plate platform meets the primer slide on my 550B.

Yep

dahermit · October 9, 2020, 08:28 AM

Quote:

Originally Posted by Kevin Rohrer

On mine, it was either when the handle hit the bench top edge, or when the press shaft buttons-out at the top of the stroke.

If you have ever removed the ram for a cleaning, you will find the when the shell plate platform is removed, the ram will drop down lower than it does normally. So I don't see the linkage as being the positive stop on the priming stroke.

dahermit · October 9, 2020, 08:30 AM

Quote:

Originally Posted by rodfac

Yep

How have you verified that...have you used strips of paper to find the contact point or have observed marks in the Aluminum (soft), of the primer slide?

dahermit · October 9, 2020, 08:33 AM

Quote:

Originally Posted by rodfac

Yep

How have you verified that...have you used strips of paper or some other method or observed a mark in the soft Aluminum primer slide where the hard steel of the shell plate platform contacts the primer slide?

**Unclenick** · October 10, 2020, 03:02 PM

Quote:

Originally Posted by dahermet

How have you determined that...

I simply looked, but the light wasn't great. I went back with a bright flashlight and looked more carefully. What actually happens is the shell plate platform depresses the spring-loaded primer-seating cup that surrounds the primer seating punch, and that cup is what actually makes contact against the primer slide, acting as the go-between for the shell plate platform and the primer slide. And yes, there is a round mark on the slide from that contact.

dahermit · October 10, 2020, 05:41 PM

Quote:

Originally Posted by Unclenick

I simply looked, but the light wasn't great. I went back with a bright flashlight and looked more carefully. What actually happens is the shell plate platform depresses the spring-loaded primer-seating cup that surrounds the primer seating punch, and that cup is what actually makes contact against the primer slide, acting as the go-between for the shell plate platform and the primer slide. And yes, there is a round mark on the slide from that contact.

Using a very bright LED bore light, on my 550b, I can see that the primer cup bottom does not make contact with the primer slide and there is no mark that indicates it does. I can see that it does not (with some difficulty) from both sides. As a matter of fact, I can see one coil of the primer cup spring between the primer slide and the bottom of the primer cup when all the way down.

I have suspected that the actual stop (at least on mine), was therefore (if not the bottom of the primer cup) the primer cup spring, collapsing until the coils make contact with each other and serve as the stop. However, I cut one coil from the spring and stretched it, mounted it and found that there was still something stopping the ram other than the spring. So the mystery continues.

COSteve · October 10, 2020, 05:44 PM

It's the post on which the primer cup sits that acts as a stop.

dahermit · October 10, 2020, 06:25 PM

Quote:

Originally Posted by COSteve

It's the post on which the primer cup sits that acts as a stop.

Examining the primer punch and the primer cup, in order for your (I assume supposition) to be correct, the primer punch would have to contact something to cause it to stop. As I examine my press with no case or primer in the priming station and press the handle back (as if priming), the handle stops. When I examine a primer cup and a primer punch, I see that the priming punch when sitting as it does in the primer cup actually will slide through the primer cup. So, it cannot be causing a positive stopping motion.

**Unclenick** · October 11, 2020, 05:26 PM

On the press there is a casting called the cartridge collection bin bracket. That casting has a clearance recess cast into it with a radiused bottom and the mouth of the recess is open toward the front of the press. At the top of the handle stroke, the handle slips into that clearance recess, but does not touch down in the bottom of it. Rather, it stops about 1/16 of an inch short of reaching that radiused bottom of the clearance recess in normal operation. If the handle went all the way to the back of the recess and touched down, you would soon find a wear mark on the handle where they meet. Mine does not have one.

The above is true with the primer slide group fully assembled. So, I did the following:

1. I took my 3/32" hex wrench and removed the primer punch, primer seating cup, and its spring. Nothing on the bar. I pushed the handle up and it went all the way back into contact with the radiused bottom of the clearance notch.

2. I put only the punch back into the slide. The handle still made it all the way back into contact with the radiused bottom of the clearance notch.

3. I put the spring over the punch. The handle still made it all the way back into contact with the radiused bottom of the clearance notch.

4. I removed the spring and put only the primer seating cup, leaving the punch in place as its guide. Now the handle stopped reaching all the way back into contact with the radiused bottom of the clearance notch, just as was the case with the fully assembled slide.

So, in addition to the circular mark on my primer slide, I have proven the primer seating cup is, indeed, the stop. If I remove it, the handle still stops, but it is about 1/16 of and inch further back because what is stopping it has changed from being the primer seating cup sandwich to being the bottom of the casting's clearance recess.

If your primer seating cup is not what is stopping your press, look at the catch bin bracket casting and look for a wear mark on the handle of your press where it is touching down there. That isn't supposed to be happening, as it shortens the maximum primer punch reach up into a case primer pocket. Only stopping on the primer seating cup produces the correct full reach of the primer punch. You may have screwed the casting to the bench too far foward and need to move it back a little.

dahermit · October 11, 2020, 08:09 PM

Quote:

So, in addition to the circular mark on my primer slide, I have proven the primer seating cup is, indeed, the stop. If I remove it, the handle still stops, but it is about 1/16 of and inch further back because what is stopping it has changed from being the primer seating cup sandwich to being the bottom of the casting's clearance recess.

If your primer seating cup is not what is stopping your press, look at the catch bin bracket casting and look for a wear mark on the handle of your press where it is touching down there. That isn't supposed to be happening, as it shortens the maximum primer punch reach up into a case primer pocket. Only stopping on the primer seating cup produces the correct full reach of the primer punch. You may have screwed the casting to the bench too far foward and need to move it back a little.

Thank you for you efforts in investigating my Dillon/priming concerns.

I should have specified that my center of interest involves only the large primer priming system, not the small. And also note that there may be some minor but significant variations between your press and mine. It is also notable that my press sits atop of a homemade (heavier gauge than a true Dillon), not bolted to the bench. I have also done due diligence in making sure the handle does not touch anything including the catch bin bracket.

Today when swapping back to the small primer set-up I noticed a very small "divot" in the right side of the primer slide (large), adjacent to the primer catcher. I also noticed that on the small primer slide, I had at some point ground a small "v" in that same area. I suspect that at some point in the past, I discovered that there was some interference at that point and dealt with it and possibly successfully. The problem could be that I just cannot remember things that well anymore, being 77 years old with memory problems due to significant White Matter being observed on an MRI. In any event, I have switched back to using small primers and don't know when I can relive (grind a "v") and test the large primer slide.

Again, I am grateful for you investigative efforts on behalf of my query. When I get around to shooing up any large pistol primed cartridges (it could be some time) I will test out the altered large pistol primer slide and report if the problem was indeed that interference...if I can remember.

**Unclenick** · October 12, 2020, 08:40 AM

Sorry to hear about the memory issues. Must be frustrating.

I don't see any divots or other issues with my primer slide, so we must be getting into the differences in our units. Sorry not to be able to be more directly helpful.

**44 AMP** · October 13, 2020, 01:09 PM

I realize this is no help, but a long time ago I had a 450, and if memory serves, it had a threaded screw and lock nut underneath the shellplate platform which allowed you to adjust where the ram "bottomed out" on the down stroke.

Does the 550 NOT have that feature???

dahermit · October 13, 2020, 03:32 PM

Quote:

Originally Posted by 44 AMP

I realize this is no help, but a long time ago I had a 450, and if memory serves, it had a threaded screw and lock nut underneath the shellplate platform which allowed you to adjust where the ram "bottomed out" on the down stroke.

Does the 550 NOT have that feature???

Nope...different animal.

October 8, 2020, 11:21 AM	#1
dahermit Senior Member Join Date: October 28, 2006 Location: South Central Michigan...near Posts: 6,501	stop on Dillon 550x Question: what on a Dillon 550x press makes the positive stop on the priming stroke. Go to your 550x and push the handle back with no case in the shell plate and tell me what stops the stroke. I think I know, just want concurrence.

October 8, 2020, 11:36 AM	#2
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	Shell plate platform meets the primer slide on my 550B. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

October 8, 2020, 08:06 PM	#4
FrankenMauser Senior Member Join Date: August 25, 2008 Location: In the valley above the plain Posts: 13,424	I think it's supposed to be the primer slide. But I had my 550B mounted directly to a bench. The stop was the handle hitting the bench. __________________ Don't even try it. It's even worse than the internet would lead you to believe. Last edited by FrankenMauser; October 8, 2020 at 10:57 PM. Reason: Dumb typo

October 8, 2020, 08:40 PM	#5
Kevin Rohrer Senior Member Join Date: May 19, 2010 Location: Medina, Ohio Posts: 1,049	On mine, it was either when the handle hit the bench top edge, or when the press shaft buttons-out at the top of the stroke. __________________ Member: Orange Gunsite Family, NRA--Life, ARTCA, and American Legion. Caveat Emptor: Cavery Grips/AmericanGripz/Prestige Grips/Stealth Grips from Clayton, NC. He is a scammer

October 11, 2020, 05:26 PM	#14
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	Going the extra mile for Dahermit On the press there is a casting called the cartridge collection bin bracket. That casting has a clearance recess cast into it with a radiused bottom and the mouth of the recess is open toward the front of the press. At the top of the handle stroke, the handle slips into that clearance recess, but does not touch down in the bottom of it. Rather, it stops about 1/16 of an inch short of reaching that radiused bottom of the clearance recess in normal operation. If the handle went all the way to the back of the recess and touched down, you would soon find a wear mark on the handle where they meet. Mine does not have one. The above is true with the primer slide group fully assembled. So, I did the following: 1. I took my 3/32" hex wrench and removed the primer punch, primer seating cup, and its spring. Nothing on the bar. I pushed the handle up and it went all the way back into contact with the radiused bottom of the clearance notch. 2. I put only the punch back into the slide. The handle still made it all the way back into contact with the radiused bottom of the clearance notch. 3. I put the spring over the punch. The handle still made it all the way back into contact with the radiused bottom of the clearance notch. 4. I removed the spring and put only the primer seating cup, leaving the punch in place as its guide. Now the handle stopped reaching all the way back into contact with the radiused bottom of the clearance notch, just as was the case with the fully assembled slide. So, in addition to the circular mark on my primer slide, I have proven the primer seating cup is, indeed, the stop. If I remove it, the handle still stops, but it is about 1/16 of and inch further back because what is stopping it has changed from being the primer seating cup sandwich to being the bottom of the casting's clearance recess. If your primer seating cup is not what is stopping your press, look at the catch bin bracket casting and look for a wear mark on the handle of your press where it is touching down there. That isn't supposed to be happening, as it shortens the maximum primer punch reach up into a case primer pocket. Only stopping on the primer seating cup produces the correct full reach of the primer punch. You may have screwed the casting to the bench too far foward and need to move it back a little. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

October 10, 2020, 05:44 PM	#12
COSteve Senior Member Join Date: September 6, 2009 Posts: 1,344	It's the post on which the primer cup sits that acts as a stop.

October 12, 2020, 08:40 AM	#16
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	Sorry to hear about the memory issues. Must be frustrating. I don't see any divots or other issues with my primer slide, so we must be getting into the differences in our units. Sorry not to be able to be more directly helpful. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

October 13, 2020, 01:09 PM	#17
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 28,833	I realize this is no help, but a long time ago I had a 450, and if memory serves, it had a threaded screw and lock nut underneath the shellplate platform which allowed you to adjust where the ram "bottomed out" on the down stroke. Does the 550 NOT have that feature??? __________________ All else being equal (and it almost never is) bigger bullets tend to work better.