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Hornaday LnL-AP Primer System Troubleshooting

Filed in Articles, Hornady LnL AP, Hornady LnL-AP Setup, Reloading Presses, Uncategorized by on January 27, 2013 1 Comment • views: 5468

Since the cost of commercial ammo has gone through the roof and availability has gone through the floor, perhaps you are thinking about getting into reloading. If so, you are probably researching everything you can about the Big Three (Dillon, Hornady, RCBS) reloading press manufacturers.

You generally won’t find many complaints about the Hornady LnL-AP press except for a few regarding its priming system.  I’ve reloaded about 20,000 rounds on mine, mostly a mixture of .223 and .45acp, and I can tell you that any such complaints are due to not understanding Hornady’s very simple priming system.

This article describes the Hornady LnL-AP priming system, the minor problems you may encounter, and how to address them. If you are having Hornady Priming System problems hopefully you’ll find this article helpful.

Acknowledgement: There is a great forum called The High Road, and on it, a member named NoFishBob created a thread describing many of these issues. My intent here is to build upon NoFishBob’s post. Many of the photos in this article are his.

Priming System Description

Hornady Priming System Problems and Solutions

Figure 1

Figure 1 illustrates the priming system when the ram is down. The primer slide (most of which is hidden from view, unfortunately) slides back and forth in a track. Attached to the side of the Primer Slide is the Follower, shaped like a pulley. The Z-Wire rides in the Follower’s groove (The official Hornady parts list calls the Z-Wire the Primer Feed Cam). As the ram is raised, the the Primer Slide is forced to travel rearward by the Z-Wire.


Hornady Priming System Problems and Solutions

Figure 2

Figure 2 illustrates the priming system when the Ram is all the way up. (The Feed Tube has been removed for clarity.)

When the Ram is all the way up, the Z-Wire causes the primer slide to move rearward. The hole in the primer slide then lines up with the Feed Tube and a primer drops into the primer slide.

When the Ram is all the way down, the primer slide moves forward in its groove, placing a primer in the correct position to be pushed up into the waiting cartridge case.

It’s that simple.

There really are only three simple things that can go wrong:

Debris in the Primer Slide Groove.

The Primer Slide moves in a groove machined into the baseplate. (The baseplate is the thing mounted on top of the Ram and accepts a shellplate.) Any debris in this groove gets pushed forward by the Primer Slide and prevents the slide from moving all the way forward. The result is that you cannot seat a primer because the primer is off-center from the cartridge case’s primer pocket.

You must be fastidious about keeping this area clean. Any time you have a powder spill the powder will work its way into the groove.  I used to use a vibratory cleaner and finely-ground corn cob to clean my cases.  A few grains of corn cob would occasionally stick to a case and end up in the primer slide groove, causing a problem.

Misalignment of Primer Slide At Top of Travel

When the Ram is at the top, the hole in the Primer Side must be perfectly aligned with the Priner Feed Tube. This is a photo looking straight down through the Primer Feed Tube and you can see the whole in the Primer Slide is exactly centered on the Feed Tube.

Misalignment will cause either a primer to not feed or for the primer to tip up on edge as it enters the hole causing the Ram to jam (because the primer is sitting there on its side).

Debris in the Primer Punch

The punch has a spring that forces the center plunger back down. If you have debris in the Primer Slide Groove, some of it may fall into the punch’s spring. As a result the plunger that pushed the primer into the case does not retract all the way. When the primer slide tries to move back it gets caught on the protruding plunger. The symptom is that the Ram cannot be raised more than about two inches before it jams.

When this happens, the way to clear the jam is to reach around under the baseplate and push-and-release the plunger a few times.  That will clear the jam. You’ve probably still got the bit of debris inside the punch though so it would be a good idea to stop, remove the punch, and blow it out with some compressed air.


That’s it.  That’s all there is to keeping the Hornady LnL-AP priming system running smoothly. With this little bit of knowledge you shopuld have years of trouble-free use of your Harnady LnL-AP reloading press.

Buy the Hornady Lock-N-Load Auto Progressive Press at Brownells

Hornady Lock-N-Load Auto Progressive Press

Comments (1)

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  1. Finally someone put the troubleshooting on the most precise way. I encountered troubles about my Hornady priming systems and this blog would help a lot of reloading fans.

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