Dillon 550 failsafe powder rod assembly


October 14, 2011, 11:16 PM
When I bought this press (used) the failsafe powder rod was not attached. Is there a reason people don't use it? Pros and cons?

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October 14, 2011, 11:29 PM
The rod has to be removed to exchange the die plate or powder measure. It snaps into place with no tools. More than likely is was simply removed to make shipping easier.

October 14, 2011, 11:33 PM
From what I can tell, there was a time when Dillon used a spring to return the powder bar to home position. Since the press uses the down stroke to seat the primer, the failsafe rod would always pull the powder bar back to home, and if it got stuck for some reason, the operator would hopefully notice something wrong. If the spring failed, it could go unnoticed and squibs would be produced.

October 14, 2011, 11:40 PM
I bought the press from someone who had bought a house and the previous owner was obviously a serious reloader. The press was set up to reload, had powder in the powder measure, and the assembly was not attached. I thought there may be a reason he took it off?

Mike Kerr
October 15, 2011, 01:04 AM
Was the Failsafe rod just laying on the bench - or was it gone - like not available at all ?


Mike Kerr
October 15, 2011, 01:19 AM
I noticed you asked for Pros & Cons on the use of the failsafe rod. My answers are 1. If its available put it on. 2. If it doesn't have one you can get an assembly from Dillon which has everyting you need ( they offer three different options if I remember correctly).

Before they utilized failsafe rods we used springs which work well but can fail you at the darndest times, and you might not even notice it until you have squibs at the range. Then they had rods with an older (simple) style linkage- these work well and are quiet. The newest ones have a double linkage system which is cool but its noisy.

Some older reloaders take or took their failsafe rods off for multiple reasons such as smoothness of return, believed quicker operation, overall brain fades etc.

As to why the previous owner took it off - (if they did at all) Who Knows - what matters is - its a safety feaure I hope you add to your press.


October 15, 2011, 01:29 AM
As stated, the fail-safe rod is a later Dillon design, replacing the spring-loaded return.

Without it, the powder bar may not return completely as the powder-thru die runs the slotted bellcrank.

If it is installed and adjusted correctly, it "helps" the powder bar to its normal position before the next operation of the handle. It does this during the primer seat stroke. (When the operating handle is pushed to the rear.)

I'm not sure you would get a squib if it wasn't installed, as the powder bar motion isn't defeated. But the powder bar travel may not be uniform without it, so the charges would not be uniform. (Less travel = undercharge)

I believe the operation of the fail-safe rod is important even if you skip Station 1 when reloading bottleneck cartridges with "prepped" brass. That is, you need to perform the primer seat stroke even though there isn't anything present in Station 1, so that the fail-safe rod fully returns the powder bar.

October 15, 2011, 10:13 AM
The failsafe rod was among the spare parts. I am fairly certain the press was used without the rod because the piece that fits under the shell plate for the bottom of the linkage was not attached either. Or as certain as I can be without watching the previous owner load.

This must be the older design rod as it doesn't look the same as the picture in the down loaded owners manual.

Thanks for the help guys...

October 15, 2011, 10:31 AM
I run two Dillon 550's and now own a 650 that will be dedicated to 45 ACP's. My 550's were pre 550B models and didn't have the ''fail safe'' mechanism when purchased. As soon as Dillon had them available I purchased two of them ever since. My powder measures were the old spring type and the 'fail safe'' saved my bacon numerous times when the powder slide got dirty and stuck in the open position. If you have the older powder measure with the coiled return spring, consider the ''fail safe'' your presses's seat belt! This item is also a safety factor on the newer powder measure's alos...otherwise why would Dillon supply it with new 550B's and XL650's. Safe loading Guys.

October 15, 2011, 10:33 AM
I'll often remove the rod when I'm adjusting a die and DON'T want the powder measure to drop powder. I'll manually cycle the bar, catching the powder in a case, then just leave it in the forward position.

I'd install the rod and check the operation of the press. If all is OK, don't try to figure out why the previous owner removed it.

October 15, 2011, 11:35 AM
Now I have a clearer picture. The spring for the return is above the powder measure bar, the po had 2 springs. I guess 2nd was for back up. I am hoping this is why it was throwing loads +/- 2/10 grain.

The rod I have has one 90 degree bend at top, whereas the picture in the down loaded owners manual has (2) 90 degree bends at the top.

This press must be pretty old. It is cleaning up nicely and with a little lubrication is working very smooth.

Thanks again for the help. I am learning this as I go and the advice is much appreciated...

October 15, 2011, 05:36 PM
The one with one 90 degree bend is the old one. The new powder measures from dillon don't have a spring at all they just use the failsafe.

October 15, 2011, 07:05 PM
Will older powder measures work with the new rod or are there other updates?

October 15, 2011, 08:10 PM
there are other updates... I don't know about an old PM working with a new rod, but I do certainly know you cant use the old rod on a new PM. If I were you I would call dillon and talk to them.. they will set you up, and probably won't even accept your money. When I bought my press It had the old PM on it.. I ordered some new PMs not knowing anything changed. I called dillon and they sent me a new failsafe rod fully assembled free. Great customer service..

October 16, 2011, 10:09 AM
Get in touch with Dillon. They offer an upgrade for some of the old measures but there is one that they refer to as a 'transition model' that the upgrade does not work on. I had one of those and since it 'didn't work' (their suggestion) ;) , they replaced it with the new model. Dillon is great like that.

October 16, 2011, 01:37 PM
Get in touch with Dillon.


The first action when you have any questions on a Dillon press is to pick up the phone. There are certainly multiple models of the 550 and its powder measure. I bought an older model PM one time on Ebay, and told them as much. They were happy to send me replacement parts free of charge.

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