Reloading 45 ACP with the Dillon 550B

The Dillon 550B (and newer RL-550B) are well-known for being solid performers that are simple to setup, and relatively affordable to setup and run. This press may not be loaded with all of the latest features (from what I know it was introduced well over 30 years ago), but it does have a “tried and true” reputation. In this post, I’ll walk you though an overview of the press, and then load some 45 ACP with it. This isn’t a typical “stock setup” – this 550B has been upgraded with quite a few Inline Fabrication upgrades (see the end of the post for a list).

Let’s get straight to it, here’s the video:

In the video I walk through the stations, here’s a bit more detail on the setup:


These stations are setup as follows:

  • Station 1: LEE 45 ACP sizer/de-primer (top), priming (bottom)
  • Station 2: Dillon powder measure with integral expander
  • Station 3: Hornady Seating die (with sliding collar, a great design)
  • Station 4: Hornady taper crimp die

This setup has been working great for me, and I like the ability to adjust seating depth and crimp separately. That’s the way I setup every press for pistol cartridges when I have the option to do so. A couple things to note here for this this press and setup:

  • You don’t have a station for powder check unless you combine seating and crimping
  • Because this press doesn’t have auto-index you have to be especially diligent to check powder levels and *advance the shellplate every time without any mistakes*

I grouped these two concerns together here because they “compound each other”. Having said that, I know people that swear by the 550B/RL-550B, and haven’t had issues with double charges.

Like any other press, how you setup and organize your gear will have a big impact on both you efficiency, and your enjoyment of the reloading process. This Dillon 550B setup features the following Inline Fabrication upgrades:

Here’s a close-up of the dual output and empty case bin setup which includes the bin barriers (improves working capacity of bins greatly):


I’ve experienced stiff and chunky priming on a couple 550’s now- if anyone has tips/tricks on smooth priming for this press, please leave a comment! I think it’s time to take my 1911 out to the range!



9 thoughts on “Reloading 45 ACP with the Dillon 550B”

  1. Hey Gavin, Love the blog and your youtube channel. Have a question for you; I really like your work bench setup and have started to make my own, just wanted to ask you how far apart are the T-Tracks and what sizes are the mounting plates that you have made out of plywood? Any info would be very much appreciated, thanks in advance and keep up the great work.

  2. Thanks for posting something on the 550B. I glad to see you’re using an assortment of dies and lock rings on this press. I never understood or felt the need for the ultramount type systems. I know they are popular but my 550B is comfortable to operate and work very well just mounted on one of my benches. I made my own bin barriers with some duct tape. I guess my methods aren’t the ultimate in expense but very functional.
    The new Lee Auto Drum and powder thru dies are replacing most of the Dillon PM for most of my tool heads.

  3. I also suffered from chunky primer seating until I tweaked the screws holding the primer bar assembly. The screw that adjusts the depth of travel is self-explanatory in use; slowly tighten or release it until the primer cup slides into the shell plate without binding. The primer bar assy is a little more complicated but works on the same principle. Loosen the screws a bit and try different positions until the primer cup doesn’t touch the shell plate – then tighten them up good. I found my break-through occurred when I realized the biggest improvement came from transverse adjustment – moving the primer bar in and out laterally, not left-right. Since I did this I’ve had butter-smooth primer seatings…

  4. Awesome old warhorse of a Dillon 550 used in your video! It would be great to know the number of rounds this machine has loaded over the years. I have a newer 550 and it’s interesting to see the improvements Dillon has made in the powder system while other components remain pretty much simple “state of the art”, much like a flat head screw driver or hammer. Manual indexing is just fine . . . as long as you have NO auto case feeder . . . auto indexing without a case feeder only increases complexity and reduces control with no increase in speed. Three things I noticed in your excellent video; 1) Wash and lube this thing! It would likely smooth out with a good scrubbing and full lube, Dillon has an excellent video on their website showing the steps. 2) It’s loose on the bench. It would definitely smooth out by being fully secured. The rocking motion I noticed while you cycled through the rounds made me cringe knowing you’d have a better experience with the press and it would work better by being fully secured to the bench. 3) The Dillon components appear to fit and handle much better with the Dillon press . . . bullet tray, strong mount, case and completed cartridge bins, even dies, etc . . . doing otherwise is kind of like trying to put Windows programs on a Mac. The only non Dillon component I’ve added is an LED light in the toolhead center hole from InLine greatly improving vision.

  5. I noticed you press rocks quite a bit when your loading. It shouldn’t be doing that. I have the RL 550B mounted on the Dillon strong mount and it is rock solid.

  6. Hey Gavin

    Long time no talk. Good video on the venerable 550B. I have experienced some clunky primer seating as well on mine. It usually starts to occur when primer components start getting a little dirty. I also load black powder 45C on mine so it gets dirty pretty quickly. I clean it regularly and make sure the primer slide mechanism is as smooth as possible. I too use the Uniquetech bearing which seems to help. The most important thing is to wait to tighter the primer assy until the primer cup is in the seated/centered position protruding through the shell plate. Doing this helps to ensure the primer cup is centered and will not snag the shell plate.

    Keep up the good work on the videos.

    Bob (in Woodinville)

  7. I love my old 550B. One thing that that I have found that keeps my priming system happy is getting a primer alignment tool from Dillon and checking the alignment occainonaly to make sure everything is in alignment and the another major fix for my priming system is upgrade I think it is on Amazon as well too.
    It really smooths up the priming system by using the bearing to counteract side support from the Op-rod pressure. I think since the plate is longer, it doesn’t allow all the priming dust and trash to get under the primer arm that moves back and forth. I can load a lot more rounds before I have to tear it apart and clean it. I use canned air to keep everything sort of clean and l add a bit of powdered graphite now and then to help keep the priming system happy. love your videos, I am a fan

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