Hornady LNL Powder Measure Modification for more precise throws

[lordpaxman]

My first modification was to peruse the blue press pages and add a super 1050 to the cart.... I have friends who swear by them and their ability to meter most powders including Hodgdon Clays and IMR Target very precisely. The CFO nixed that mod.

I'll try to keep this concise, but let me back up a bit. My LNL measure does really good (meaning very precise) with some powders, like Titegroup, AA2, N320 to name a few. It does pretty good with others like WSF, WST, Sport Pistol, 244. However, when I tried Clays, and Target, and Red, with a small charge in the 2.5-5 gr range, I routinely saw +/-.5 gr, and occasionally swings of .8gr. With the faster powders, and small charge weights, that's unacceptable.

The LNL rotor rotates down across the back of the powder hopper, however when I watched the action, I could see two things that could be improved. The first was the curvature of the hopper, and the second was the angle the rotor intersects the powder cut-off point. It appeared powder would be both compressed in the cavity as well as sheared off the top as the rotor rotates downwards.

I wanted to modify this to be more like a baker shaving off the top of a cup of flour with a knife. I added a fillet of epoxy with the rotor in place and just enough so the small cavity in the pistol rotor was completely exposed.

Preliminary testing shows a marked increase in precision. For IMR Target, Avg 3.0gr, +/- .19gr, Clays, Avg 2.1gr, +/- .07gr, and N320, Avg 3.1gr, +/- .06gr. The sample size was 12, it's not statistically significant but the results look encouraging.

I'll add a few more details just in case anyone's interested. I scuffed the back of the powder hopper with 220 sandpaper and cleaned with acetone. I had three coats of Johnson's paste wax on the rotor and rotor housing, and filled the pistol rotor cavity with wax as well. I carefully used a small wooden tool to caulk the rotor/housing seam with wax as well. I did want the rotor to rotate after the epoxy sets up. I had some West Systems 105/206 epoxy with 406 filler and thickened the mix to be quite viscous, about heavy cream to hot peanut butter consistency. The epoxy should be able to flow and fill the circular void in the back of the powder hopper, but not too loose so it runs everywhere.

I didn't check the rifle rotor cavity as this press sees pistol only. Time will tell how this performs but I'm optimistic this will help. It will most likely wear over time so I'll need to keep an eye on it. I also noticed that for the powders I tested, the prior micrometer setting produced about a .5 gr greater throw. That further suggests the powder was being compressed in the cavity somewhat. How much would depend on the specific powder characteristics. It also means all those metering inserts I had calibrated will need to be re-calibrated.

Merry Christmas!

 

[Texas10mm]

At the 2.5 gr range of those powders you're at the ragged edge of what the Hornady powder measure is capable of. I had no problem with mine with other powders. There's a reason that Dillon sells an extra small powder bar for those small charges. I had to add one to my new Dillon 650 order because I'm going to be loading the .32 revolver cartridges and some of those charge weights are 2 gr or so.

 

[egd]

If you are seeing a .8 gr variation in a ~5 gr load can you shoot well enough to tell the difference in accuracy? I sure can't. Congrats to you if you can, but that's acceptable to me. Obviously YMMV.

 

[edwardware]

@lordpaxman This needs pictures, at least of the finished product. I've been annoyed at my LNL's charge variability, and might have to do your mod.

Also, I'd like to know about the durability of the epoxy cutting edge.

 

[Jesse Heywood]

If durability is a concern, try some machinable metal epoxy. We have used Devcon for some repairs in castings that we didn't consider weldable.

 

[gojones]

Might just need to make a youtube video on this if it actually does improve throw accuracy for these smaller cases.

 

[cfullgraf]

I wanted to modify this to be more like a baker shaving off the top of a cup of flour with a knife. I added a fillet of epoxy with the rotor in place and just enough so the small cavity in the pistol rotor was completely exposed.

Sounds like an idea with some potential. Remember, a picture is worth a 1000 words.

Devcon or something similar may be a bit more durable.

As delivered, I've found the Hornady L-N-L powder measure to be inconsistent with small powder charges. If the modification is easy to do and durable, it may be a good modification. Thanks for the information.

I have the Dillon small cavity charge bar that I use for loading 380 ACP on a Dillon SDB. It does a good job with the small powder charges.

Also, I have a Redding 10-X powder measure that I have modified to be mounted in the Hornady L-N-L powder drop die. The 10-X does a well measuring down to powder charges suitable for 25 ACP. I pretty much use the modified Redding 10-X on my Hornady L-N-L, RCBS Pro2000 and Dillon BL550 exclusively.

The modification to the Redding 10-X is primarily tapping the discharge of the powder measure to accept the Hornady drop tube. This works well with the Redding BR-30 powder measure.

As an aside for the durability of JB Weld, another epoxy compound. I have modified some shell holders for use with an RCBS APS priming tool. The plastic sleeve that RCBS provides with the tool to sleeve the shell holder down to the size of the appropriate primer size is not very durable. As a trial, I modified a shell holder with JB Weld to reduce the opening in the shell holder to the size of a small primer. The modification works well improving the reliability of the priming tool. But, I can see the primers shaving a bit of the JB Weld when a primer is seated.

I've taken to modifying the shell holders with a brass slug and brazing material and this seems to be more durable than the JB Weld.

In any case, thanks for the information and the modification.

 

[Walkalong]

As cfullgraf points out, the reloading companies fix for large measures not throwing small charges well are "pistol" measures designed to throw smaller charges.

Remember, a picture is worth a 1000 words.

Sure is and would love to see some.

 

[Jim Watson]

Interesting. I have been following the Mark 7 threads on Benos with amazement. Apparently the fix for an inaccurate powder measure on your $5000 loader is to install a Hornady or Dillon measure while the manufacturer tries to fix theirs.

 

[Texas10mm]

If you are seeing a .8 gr variation in a ~5 gr load can you shoot well enough to tell the difference in accuracy? I sure can't. Congrats to you if you can, but that's acceptable to me. Obviously YMMV.

A .8 gr variation on a 5 grain drop means a drop of anywhere from 4.2 gr to 5.8 gr. That's WAY dangerous. 4.2 is likely to result in a stuck bullet and 5.8 is likely to result in a case failure or worse.

Do you actually reload?

If the OP is trying to drop 3 grains and getting a .8 gr variation then that's even more dangerous.

 

[lordpaxman]

Ok, Ok, some of you like pictures, I get it! Really I do... I'll try.
Before:


After:



Viewed from bottom:



I tinted the epoxy so it would show up better in the picture. Not really, I had some fill work to do on a black walnut live edge coffee table top, but the black does show up better. I had considered a small strip of metal in the epoxy to avoid the potential wear issue, but, thought I'd try this before going too crazy.

AdApologiesVance if the pictures aren't in the correct format. The "Upload a File" worked, but then I had the choice of thumbnail or full image and I took the latter.
Cheers!

 

[edwardware]

Ok, Ok, some of you like pictures, I get it! Really I do... I'll try.

Cool, now I see it. I will have to try that!

Edit: did you do anything to make the poly tube stick back in the housing after removing it? I've caught mine starting to back out a few times, and that would be a huge expensive mess.

 

[Reeferman]

That’s interesting. I load a ton of 38 wad cutters with Bullseye and 231 anywhere from 2.7 to 3.5 grains and my LNL measure is never off more than .1 grains.

 

[lordpaxman]

Edit: did you do anything to make the poly tube stick back in the housing after removing it?

Absolutely. Duct tape. I've seen others drill and tap for set screws, but I'm not ashamed to use tape. I've only it had it fall off once, the hopper was half full - that was BT (before tape).

I load a ton of 38 wad cutters with Bullseye and 231

Yes, some powders and measures do very well. If you're happy, I'm happy. Unfortunately mine doesn't perform as well with certain powders, and, I didn't want the equipment to dictate what powders I should use.

 

[CoalTrain49]

At the 2.5 gr range of those powders you're at the ragged edge of what the Hornady powder measure is capable of. I had no problem with mine with other powders. There's a reason that Dillon sells an extra small powder bar for those small charges. I had to add one to my new Dillon 650 order because I'm going to be loading the .32 revolver cartridges and some of those charge weights are 2 gr or so.

RCBS also has a small and large capacity drum for their Uniflow powder measure. I had the large one but was loading a lot of 3.5-5 grain loads. It didn't work real well for that so I bought the small version with a larger micrometer. That one keeps the throws +/- 0.1 grain. I can live with that. They both chop flake powder tho, don't know how to get around that.

 

[Jim Watson]

The Uniflo Small is pretty good.
I started out with a Redding which was and is fine with rifle loads, but the "pistol chamber" is made as an insert in the rifle drum and is not machined precisely enough to come dead flush. Fine pistol powders smeared in the mismatched area.

 

[egd]

A .8 gr variation on a 5 grain drop means a drop of anywhere from 4.2 gr to 5.8 gr. That's WAY dangerous. 4.2 is likely to result in a stuck bullet and 5.8 is likely to result in a case failure or worse.

Do you actually reload?

If the OP is trying to drop 3 grains and getting a .8 gr variation then that's even more dangerous.

Yes, you're right. I wasn't thinking straight. I was mixing up decimal points.