1 post
Joined November 2017

RL-550 B Primer system

I am not here to simply jump on or trash the Dillon RL-550, It was designed long ago, and I assume when it was designed it was quite a feat. In my observation in 2017, it needs to be improved.

I am loading .30 Cal. M1 Carbine loads. small rifle primers.

I have had a lot of problems with the primer operation, more than any other part of the machine, The primer system is the weakest mechanically and the least reliable.

I have analyzed this system, and I urge some machine designers who reload and have knowledge on high speed machinery, machine materials, tolerances and such design principals to look this system over as I observe the following.

1. The slide bar, slide opening, is too sloppy. It has to much lateral slop.
2. The materials of this bar may need to be case hardened, or made out of a material that is harder as well as the housing it slides on, not aluminum.
3. The principal of the off set rod, that then depends on both its height setting, but more importantly, the PLASTIC ROLLERS THAT IT RIDES ON, HAVE LATERAL SLOP ON THEIR SHAFTS OF 1/4" or so, and the roller is able to strike and jam against the housing, this should not be.
4.The retract spring, in conjunction with the slide coefficient of the bar and the lateral slop allow it to bind up and sometimes slam , throwing the primer off the cup.
5. The cup height is critical, but the point where it sits under the primer tube is again a hit and miss operation, sometimes dropping no primer, or dropping several rather than just one.

I have removed and cleaned all moving parts, carefully adjusted the rod height and alignment with rollers, and still, it slams, and mis feeds primers.
I replaced the rod, cup and spring, retract spring, and as i said cleaned the slides, and made sure that the allen screws were tight that hold the assembly together, but not too tight so as to cause a bow in the housing or assembly.

I tried lubricating the slide with light oil, then silicon spray, very light application, no permanent solution. It need a redesign, in my opinion, including different materials at several points, and something better than the rod and roller actuator. If you have a fix at Dillon, share it with me please, jerry Dunford
2,820 posts
Joined July 2007

RE: RL-550 B Primer system

For best possible assistance, we suggest you phone us when you can be in front of the loader. Below is a link to suggestions for common primer feed issues.
25 posts
Joined November 2007

RE: RL-550 B Primer system

If your machine has seen a lot of use the lubricating finish may have worn off the primer bar and needs to be replaced. Dillon replaced mine after I used it for years. Runs like a dream now.