LNL AP primiing system notes

[nofishbob]

The purpose of this thread is to help those who are having problems priming on their LNL AP press. When I read about folks having these problems I feel lucky that I have escaped these problems for tens of thousands of rounds.

I feel that if I could get together with someone who is having priming problems, we could compare my working press with the one having problems and see a solution relatively quickly. Since we are all spread around the country (world?) I hope that these pictures and descriptions can help someone who is having problems see a LNL AP that works, and then figure out what might be out of spec on their press.

Here goes.

I have split priming problems into two groups: the feeding of the primers from the primer tube to the primer punch, and the seating of the primer in a case.

Primer feed:
The only real adjustment on the entire priming system is the primer shuttle cam wire. This wire is adjustable both vertically and horizontally. If this cam wire is misadjusted, there will be no priming joy.

The two goals are to have the hole in the primer shuttle PERFECTLY centered when the ram is at the top of its stroke, and to have some dwell time at the top of the ram’s travel where the shuttle does not move for a significant amount of press ram movement. This allows the primer enough time to drop into the hole in the primer shuttle without catching or tipping.



Please note the geometry of the primer shuttle slot in relation to the primer shuttle and the primer tube base. The primer punch and primer punch nut are absolutely flush with the bottom of the primer shuttle slot so that they do not catch and tip the primers as they are slid over the punch assembly.



Note also that the primer itself is below the level of the top of the primer shuttle, again, so the primer does not get caught on the case as it slides over it.



The hole in the primer shuttle is EXACTLY centered over the primer punch. This is where I have had powder or dirt get between the front of the primer shuttle and the end of its slot, causing misaligned primers trying to be forced into the case.



Cleanliness is really important here. I use Hornady One Shot dry lube on the primer shuttle and slot with good results.

Finally here is a picture of how the primer feed tube should look when properly assembled:




Primer seating:
There is no adjustment on the LNL AP for seating depth, nor is one needed if the system is working correctly. The press is designed to be able to seat a primer deeper than ever required so that the operator stops the upstroke of the press handle when he feels the primer bottom in the primer pocket. A lot of parts have to work together to allow this to happen.

There are many threads about the “dimple” or “divot” that the primer punch makes in the press frame. This dimple introduces another variable that, while unwelcome, is not hard to eliminate as a problem.



The concept here is that when the primer punch nut bottoms out against the press frame, the primer punch should extend up a sufficient distance to fully seat a primer, PLUS a bit of a “fudge factor” to account for variations in case head dimensions, shell plate flex, coaralis forces, etc. An easy way to check this is to place a primed case over the primer punch (with no loose primer on the punch) and then lower the ram as if priming a case. The case will be jammed up against the shell plate with the punch in the primer pocket, stopped by the primer there. While holding the press handle in this position, look to see if there is a gap between the primer punch nut and the press frame. I see about 0.040” on my press.



If there is no gap here, the primer punch is not able to reliably properly seat a primer. Common causes for this are a press frame dimple that is too deep, a primer punch that is too short, a primer punch nut that is too long, or best of all, a combination of all of these.

If your dimple seems too deep (is this too personal?) an easy way to see if it is a problem is to repeat the above test with a thin, flat piece of metal over the dimple. If you still cannot achieve a gap between the primer punch nut and this piece of metal, I would look at replacing the primer punch assembly. I have heard good results from people dissembling the primer punch assembly and grinding the primer nut slightly to allow the ram to stroke down a little further.

The primer system on the press shown works without drama. I never modified it or polished it. I have fed all common brands of rifle and pistol primers without a glitch that was not related to some foolish thing that I did. I think that tolerance stacking, as in some minimum-sized parts assembled with some maximum-sized parts, conspire to make other’s LNL AP priming experience 180 degrees different than mine. Hopefully, my description and pictures will help those having priming problems to diagnose and repair their press in less time than without.

Good luck!

Bob

 

[1in9twist]

Great post Bob!

I removed the primer slide from my press and lightly chamfered the bottom of the leading edge to give that one rogue piece of powder somewhere to go and not stall out the press.

 

[Striker Fired]

For allowing the option to seat deeper ,whether the dimple is to deep or stacked up tolerances, I am making .03" longer pins for this. I have 12 made right now and am testing to see how things work. I also have another idea I'm going to try with this pin to make it wider where it hits the frame so the dimple doesn't form in the first place.

 

[Blue68f100]

Bob, Nice write up. I have one of the earlier press and do not have the primer problems ones speak of, too.

For those that do not have enough travel to seat the primer due to a dimple, one can simply place a piece of shot into dimple. Or if your good with tools you can use the seater as a guide to drill the dimple so you can put a piece of steel rod in. It does not have to be long 1/4" will be more than enough.

Hornady has also been supplying extended seating pins, too. Just have to give them a call.

You have to be careful with anything that will raise the bases height. Steel setting over the dimple to cover it. This will impact the ride height, raising the primer plunger when the press is at rest.

If you have excess base to shell plate clearance, on all plates. Make sure the retainer bolt is tight. If you need to lower the shell plate remove the excess from the drive hub.

 

[mizer67]

My dimple is deep. My nut bottoms out on the press frame leaving no gap.

I've tried several solutions meant to extend the length of the primer ram travel, with no success, even though the case is held in place at station #2 with the primer ram at full extention.

I appreciate the write up and effort with the extended primer rams you're making.

 

[Jeff H]

I don't have a LNL yet, but I'm thinking that you could probably fill that primer dimple with some JB Weld. That stuff sets up pretty darn strong.

 

[Blue68f100]

Mizer, This is a pretty big dimple if that's the case. Have no idea where your located at, but I have the necessary tools to repair it. If you have access to some shot, just drop one in the dimple and see if it will give you the necessary height to correct it.

 

[REL1203]

I have a dimple on mine from priming, i solved the problem by putting a dime in place, and generally have to replace the dime every 5k rounds or so and it works nicely.

 

[nofishbob]

REL1203 Wrote:

I have a dimple on mine from priming, i solved the problem by putting a dime in place, and generally have to replace the dime every 5k rounds or so and it works nicely.

This is really interesting, in that I always thought that the depth of the dimple was a function of the hardness of the press frame in that area, and that presses with deeper dimples were just a little softer there.

The fact that you are able to put a dimple into a dime implies that there is something else going on. I wonder if you are just using a lot more priming force than I am? This seems unlikely.

Also wonder about axial motion of the ram while the primer punch is under load allowing the primer punch to gouge metal out rather than just push straight down.

Bob

 

[GJgo]

I also use the dime trick to defeat the dimple, and I also have no gap when lowered in position. W/O this I had proud primers from the dimple. With this I have flush primers. If I hand prime my primers get fully seated, so I know there's room for improvement. The issue with many, including me, is that the primer ram is simply too short. I've contacted Hornady CS about it, asking if they would make longer rams & they declined. This was years ago however so perhaps they could use another call.

Striker Fired, if you have the tooling to produce these at spec'd length I imagine you'd get some sales from people such as me. It's such an easy problem to solve.

Bob, in my unit there is definitely some axial motion in the frame when I seat the primer. Seems less than ideal.

 

[1in9twist]

A "new to reloading" buddy of mine brought over some rounds that he had loaded and asked me why the primers have a dent right in the middle of em?

We went over to his house so I could check out his primer seating pin and found a .015 high "post" right in the middle of it, left over from being parted on the lathe.

 

[Striker Fired]

Yep, I have to turn them around and face mine off to square the face up.

 

[scotch827]

This is the first I heard of the dimple. I just got done doing 5.56 LC Brass. This is the first rifle brass I did on my LNL. I ended up hand priming them to get them fully seated. I have a Sinclair hand primer and I had to give them a good push to fully seat them. After reading this, I did a few more with a dime over the dimple and still had to hand prime them, but not as much. I think I am going to hand prime the 5.56 cases. Being able to use the case feeder to size, then to add the powder charge and seat the bullets still saves a lot of time.

 

[GJgo]

I loaded a bunch of 10mm & 44 mag today with my LnL. I realized a couple things, wanted to point out. Same situation in both cases.

With no round in the station my primer punch nut will bottom out on the dime. When priming a round however, it does NOT actually bottom out on the dime- I'd estimate there's about a .030" gap. However, the ram is at a hard stop- even with this gap it will not insert the primer any further. The assembly is slightly torqued laterally at this point, and there is a slight amount of deflection I can feel with my finger between the shellholder & the base- IOW enough pressure is being applied to bend it a bit.

If I remove the primed round the primer is dead flush. If I then use the hand primer to seat it, the primer drops .010" into a proper seating position. So, this begs the question, would a ~.010" longer primer searing stem solve this problem, or is there some other mechanical thing going on, such as flex between the base & the plate? Yes, the nut is torqued tight.

 

[Striker Fired]

I have my pins .030" longer than the factory ones,They are good to go, so if anybody wants one let me know. They allow .03" more travel because of the extra length and will hit the press base sooner than the factory.
If some presses need even longer ones,I can make them also.

 

[Blue68f100]

Spec should only be 0.003-0.004" below flush. Seating them 0.010" deep either tells me your crushing the primer or the pockets are too deep. Have you confirmed that the seater is capable of seating them beyond flush? Do you have enough upward travel with the seater plug? Your gap at 0.030 is in the ball park if the primer is seated. But if the ram will not go lower than that with no brass in the shell holder you have a seater plug out of spec, which a call to Hornady will fix.

Remember excessive clearance between the base and shell holder also comes into play as to how far you can seat the primers. Hornady Specs this at 0.010", mine runs 0.003". This can be reduced by cutting the drive hub down if needed. But in any case I would not go below the 0.003" or it may cause dragging.

My 4yr old press has a dimple that is deep enough to still seat primers to the proper depth but I have no more margin any more. I took the seater assembly apart and used the body as a guide to drill out the base so I could screw in a SS set screw. I determined that the end of the primer seater pin would not go inside where the allen head is at. It requires a 90deg angle drill and a short drill bit to do this. I also use a bottom hole tap to thread in a 8-32 thread for the set screw. With it setting flush I now have more than enough range. I have some 3/16" SS rod that I was going to use but did not have a spare drill bit to cut down to fit between the base and frame. If I have a problem with the set screw I will use the SS rod.

The ram losses leverage once you go a short distance. So apply enough force to torque the linkage is not doing much good.

I'll post some pictures later today.

 

[Striker Fired]

Being a machinist I can say by using the baseplate or the nut as a guide for the drillbit will end up with egging out the hole,depending how perfectly straight the drill is held.We use hardened guides so that doesn't happen. While some may get it good enough others will wreck the hole and end up replacing a piece for no real reason.That "solution" still doesn't address the problem of the factory pin not having enough travel on some presses either, which is why some get such a deep dimple.

 

[Blue68f100]

The factory pin does have enough travel when the presses are new. Even though some are having a problem of not seating them below flush. I think the key here is that you need to do it in one smooth motion. I had problems with this when I was using a chair with caster. I switched do a std chair and I was able to generate enough force. I did not have this problem when new and only reached the point of having no reserve at ~30k rounds. Also I find that the 9mm is harder to prime than 45acp. I did notice one of the primer punches is more pointed than the other. I do get the ~0.040" reserve when ever I use a plate under the pin.

I have been around R&D machine shops (internal) for 25+years. And these shops have some of the best machinist around, for high precision work. Any time your free drilling you have the chance of egging, due to the drill not being supported. I'm not sure you even have the equipment to get inside the frame and drill it fully supported, none of the machine shops I worked with had anything that compact. The casting is not flat so using guide blocks don't work too. The location on the bottom of the frame puts it into a transition area for the ram support. So doing this from the bottom would not be easy at all. But my main concern was to protect the threads encase something slipped. I had to raise the ram in order to have room to get my 90 drill with the bit in between the frame. With the right size bit that matches the hole in the primer nut there is no chance of walking. The dimple works as a center drill in this case. Does not really matter though, as the only purpose is to put a harder material down for the primer pin to contact. Took longer to get the tools needed together than it did to do the actual work. I started to just drill it to a 3/16" hole and drop a piece of SS rod into the hole. I discovered that the set screw head is shaped for the primer pin to contact nicely.



And the gap when primer is seated is ~0.040". This is the design buffer, if your dimple is this depth you have no reserve.

 

[breyton490]

Blue68f100,

Did you drill / tap completely thru the press? In your picture it looks like the set screw is installed from the bottom in order to have crown of the screw at the top of the press...


...........
Disregard the post.. just looked at my press and see the location at the bottom of the dimple runs into the ram boss support. there really is not a way to drill completely thru....

 

[Blue68f100]

No I just did 1/4" so the setscrew bottoms out. If you go all the way through you end up into the webbing area of the ram. Besides all you need is a hard surface for it to contact.

 

[nofishbob]

Blue68f100-

That is a really neat way to solve this problem...well done!

Bob

 

[germ]

The following point has been brought up in at least one previous thread. Other possible factors to keep an eye on are coil bind of the 2 springs involved. A. the large spring over the primer discharge tube. B. the spring on the primer pin.

With no case in the shell holder, bottom the ram and look to see if the "nut" is contacting the chassis. If it isn't, then it's conceivable that coil bind of one or both springs could be an issue for your press. That said, this doesn't conclusively mean that this is your problem. As has been point out previously, considering the LNL's limited priming range movement, tolerance stacking of all the various parts could easily account for many if not all of the complaints. Don't overlook anything.

I like the set screw solution. I've posted about this idea before but haven't had the need to try it out. Having some adjustability seems like a no-brainer to me. I think I'd use some teflon tape or a tiny spot of blue locktite on the thread though, because the rotational force of the primer pin spring could possibly cause the screw to change adjustment over the course of many rounds.

For those having powder build up in the shuttle area, consider charging in station 3 instead of 2. I use an m die in station 2.

<edit>Turns out the "previous thread(s) I was referring to are on castbooits</edit>

 

[Driftwood Johnson]

Howdy

No JB Weld will not do the job. Tried that. It is too brittle and after just a few strokes the punch chews up the JB Weld.

My solution is pretty low tech. A 1" X .060 thick fender washer, contact cemented in place.



A quarter will also work in a pinch. Yes, a dime will dent. There is a lot of force being placed on whatever the punch bottoms on. A lot of force centered on a very small diameter. A dime will dent, a quarter will not, and neither does my washer. .060 is not too much height, the punch works fine.

That photo of the underside of the primer feed is very important. I discovered through trial and error that having the inner tube flush with the bottom of the primer feed housing can cause primers to hang up. About half the thickness of a primer is good for clearance. It allows a little bit more leeway in the primer feeding into the primer pocket of the case.



In this next photo, ignore the Lyman BP powder measure. Look at the 'gravity assist device' poking up out of the primer feed assembly. A piece of brass rod, I think .156 in diameter. Puts a little bit more pressure than gravity alone to keep the primers feeding down. I think Hornady finally wised up and now they are including a plastic version with the press.




One other thing I don't think anybody has mentioned. Every so often you have to disassemble the primer punch and clean it out. Powder residue, primer residue and other gridue can build up inside, preventing the punch from lowering all the way. This in turn can leave it slightly proud, causing primers to hang up as the shuttle moves them forward. It is very tricky taking it apart, there is a tiny e clip that has to be popped off without allowing the spring to send it flying. Even trickier reassembling it, trying to pop the clip into place while fighting the spring. Worth a trip to the hardware store to pick up a couple of extra e clips. Bring the punch along so you get the correct size. You will be glad you have some extras at some point.

 

[Bowfishrp]

Cleanliness again is the key. I had a couple pieces of brass that still had a lot of media in them and when I punched out the primer the media got everywhere. I found that the media had broke down into smaller pieces and got INSIDE the primer punch. When this happened, it would not go back down and the slide would not come back all the way. It took me a few minutes to figure out why but I didnt have to take apart the punch to get it cleaned out, which was nice.
I did put my slide on the bench wheel and polished it up nicely and added a little graphite powder that I had left over from my son's derby car and it slides better than new.