How to tune the Hornady Lock-N-Load AP progressive press

[Tzed250]

I received a Hornady LNL AP for my birthday. I have read a great deal about the care and feeding of these machines, and the trials and tribulations that some experienced. My press ran well for me after the initial setup, but there was one issue that bothered me. At index on the downstroke of the ram(handle moving up), the shellplate would jump the last few degrees as the balls went home into the detents. No amount of tuning with the pawls would cure the abnormal movement. Closer examination showed that the shell plate was riding slightly above the sub-plate until the balls started to ramp into the detents. As the balls tried to go home the shellplate would leap forward and then sit down onto the sub-plate. This was not so bad except for the fact that I was loading .40S&W and the flake powder would occasionally hop out of the cases. I went looking for a solution. I took the shellplate off and then removed the sub-plate, exposing the drive hub and drive shaft. Seeing the relationship of the parts showed that the height of the drive hub and the height of the sub-plate set the clearance for the shellplate against the sub-plate. I called Hornady CS and described my problem. They sent a new drive hub but it was identical to the one in the press.

What follows is my solution to this problem.

I started by measuring the height of the drive hub and the height of the sub-plate. I found that the drive hub was .014" taller than the sub-plate. This difference is what allowed the shellplate to float above the sub-plate during indexing. I am a machinist and I knew the issue could be solved on a milling machine, but I wanted to come up with a no-cut solution. The drive hub is 1" in diameter and the ram area that it sits in has a 1.562" bore. I began to search for a shim set that would work and found one without to much trouble or cost.

Now to the good part.

This is the shim assortment, with sizes from .001 to .125". 1"ID and 1.5"OD. $7.90 to my door from eBay.


Untitled by zweitakt250, on Flickr


Here you can see the drive hub sitting on the drive shaft.


Untitled by zweitakt250, on Flickr

Measuring the drive hub from shoulder to face shows that its critical dimension is .942"


Untitled by zweitakt250, on Flickr

Measuring the sub plate shows a height of .928"


Untitled by zweitakt250, on Flickr

This results in a .014" clearance. I knew it needed to be less. I decided to try a .004" clearance. Using the .01" shim showed great improvement, but I thought the clearance could go to .003". No .011" shim is provided so I made a stack out of a .005 and .006" shims.

Checking the stack.


Untitled by zweitakt250, on Flickr

The shims in place on the drive hub.


Untitled by zweitakt250, on Flickr

Now when the shell plate is tightened the drive hub will be pulled barely above flush, keeping the shellplate in contact with the sub-plate and making the indexing of the press ultra smooth.


Untitled by zweitakt250, on Flickr

If you read much at all about the AP you will find many that complain about the lack of ability to seat primers below flush. My first run of 100 rounds resulted in two high primers, the rest just flush. I determined that this was also a result of the shellplate rising from the sub-plate. Pushing harder on the handle only resulted in the primer punch housing bottoming against the frame. Now with the clearance set the press will seat primers below flush with ease.

I hope that this thread will help those with a Hornady AP to create better ammo and be able to enjoy their press even more. Thanks for looking!

[Quick Draw]

Great info!

I have a different problem with my Hornady AP. No matter how I adjust the pawls and lubricate the detent balls my press does not index quite all the way to line up primer sweater with primer pocket. CS said to adjust pawls more.
My current solution is to operate handle then take a slight partial stroke to complete indexing shell plate to detent position then continue normally. Of course this is very slow.

Any theories on a solution?

[Tzed250]

Great info!

I have a different problem with my Hornady AP. No matter how I adjust the pawls and lubricate the detent balls my press does not index quite all the way to line up primer sweater with primer pocket. CS said to adjust pawls more.
My current solution is to operate handle then take a slight partial stroke to complete indexing shell plate to detent position then continue normally. Of course this is very slow.

Any theories on a solution?

Sorry for not getting back sooner. The first thing I would look at would be what I outlined in this thread. Beyond that, you might call Hornady CS and try to get ahold of Seth. He said that there was a batch of presses made where the toggle was machined incorrectly and that the timing could be affected.

[SteveL]

Thanks for the info. I have one of these presses that I haven't set up yet. I'll keep thus in mind when I do.

[cdb]

Any chance you have a link to the shim set you found?

[Quick Draw]

Thank you for the response. I will contact Seth with my serial number and see if he can help.
This problem has been frustrating but the AP is a great value if I can just resolve the timing issue.

[Tzed250]

Any chance you have a link to the shim set you found?

http://m.ebay.com/itm?itemId=321269056317

[royal]

Thanks for sharing your fix, great post. Loading pistol with certain powders requires me to apply downward pressure on the shell plate while indexing to avoid the "forward click" mess. Your solution explains why that's the case. What I'm not quite picking up is how you performed your tolerance (difference) measurements to determine what shims to use. I have a caliper but none of your machinist tools. Thanks again.

[Tzed250]

Thanks for sharing your fix, great post. Loading pistol with certain powders requires me to apply downward pressure on the shell plate while indexing to avoid the "forward click" mess. Your solution explains why that's the case. What I'm not quite picking up is how you performed your tolerance (difference) measurements to determine what shims to use. I have a caliper but none of your machinist tools. Thanks again.

A caliper is all you really need. I used my depth micrometer to measure the height of the sub-plate so that I wouldn't have to completely remove the sub-plate from the press. To be able to measure the sub-plate with a caliper will require that you remove the spent primer drop tube from the sub-plate. Once you have the sub-plate off then you can measure its height using the caliper. A less exact method would be to remove the case retention spring from the shellplate and then measure the shellplate/sub-plate clearance by slipping feeler gauges between the two parts. This would get you in the ballpark. The final determination is in the operation of the press. If insufficient clearance exists there will be noticeable drag during indexing and the pawls will release with a jolt. If this happens then more clearance(less shim height) is needed. The sweet spot on my press was at .003" clearance. The good thing about the shim kit I listed is that it will allow adjustment in .0005" increments.

[Colt guy]

Thanks for posting this I too have had trouble with powder spilling out of pistol cases when indexing. Now I just need to get the shim kit

Thanks Again Glad you were able to figure it out