View Full Version : Opening up Lee Sizers?

Magnum Mike
07-25-2005, 02:25 AM
Ok, i am sure this has been discussed to a degree here somewhere (but a quick search found nuttin) so i would like to poll the group as to the best way (best way meaning - most accurate, maintaining roundness) of accomplishing this task from your experience. I am wanting to open up a lee sizer to around .414" (from .410") so that i can size down bullets that are already lubed and sized .417"

How would you/do you open up a lee push thru sizers?

I found the following hone at Mcmaster-Carr,
4424A12Flex-Hone Cylinder Hone 1/2" Cylinder ID, 240 Grit, 8" O'all LgthIn stock at $12.45 Each

Would you use something like the above OR use the "sand paper on a stick" routine to accomplish this task. Would like to hear from you guys that have experience with this....

07-25-2005, 03:56 AM
Subject: How to hone a size die
Date: Wed, 1 Jan 1997 01:54:53 -0800
From: Buckshot

Oft times we find ourselves needing a bit more girth in a bullet to please a particular firearm. And, as sometimes happens the size we need isn't available or we don't want to pay for the custom manufacture of one. You can do this yourself and accomplish very accurate results for just a few cents worth of materials (not counting the size die) and a bit of time.
What you will need:
1) A size die that is as close as possible to what you want
2) A length of steel rod that is close to 3/4 of the diameter of the existing die, and long enough to protrude at least 2" beyond both ends of the die.
3) Wet or dry emery paper of 320, 400, and 600 grit. If you do need to remove more than a couple of thousandths you should also include 220 grit. Actually the 400 will finish the inside well enough, but hitting it with a bit of 600 sure slicks it up.
4) Oil. Most any oil will do.

What you do:
The paper should be cut long enough to extend out either end of the die, almost as long as the steel rod. Wrap your starting coursest grit paper around the steel rod a couple times and apply some oil to the paper. Insert the covered rod through the size die. With just your thumb and a couple fingers on each end of the rod, roll it up and down your thigh (while sitting) applying only mild pressure. The reason for using a rod as large as possible, is to keep from tapering the inside of the die, by having a slender rod bend under pressure.

This will get your pants leg fairly well oiled up, so use old pants. Or you can staple a bit of cloth to a length of wood. Most any surface that the die can turn on is fine. I use a piece of mud flap screwed to a bit of 2x4, and clamp it in the vise, and it's a good working height.

Roll the steel rod occasionally as only a small portion of the paper is in contact with the interior of the die. You should also swap the die end for end every now and then to make sure the metal removal is as even as possible. Remember the throat of the die is tapered to admit the bullet and we're only wanting to open up the actual sizing portion of the die.

When you check your work you don't need to put the die back in the press. Just drill a hole in a board bigger than the bullet and place the die over it. Place a bullet in the die and tap it through. Remember to leave a bit of metal to remove for your polishing down to final size with the finer grit paper. The first time I did this I just took it down to where I wanted it without thinking of the finish. It works, but you do need a bit more effort to get the bullet in and out, and it just isn't the right way to do it!

Your existing plunger will still be fine in the honed out size die, unless you opened it up several thousandths. Even then it may still work fine, but you'll need to pay more attention to the lube consistancy and the amount of pressure you exert on the lube reservoir.


From: Leftoverdj

There's a easy way with the Lee push throughs. Just coat some cull bullets with fine valve grinding compound and shuck them through. I start with 320 grit and four or five bullets. When one comes out the top, I run it through again and repeat until the bullets are going through very easily. This usually opens about .0015. If you want less, stop earlier, clean the die, size and measure. When I have it close, I clean up, coat some more bullets with 600 grit and shuck them through to polish. The 600 grit removes very little metal.

Mark the finish size on the lock ring. I don't have any marking means that will touch the die itself, but a stamp or an electric engraver works nicely on the ring.


07-25-2005, 08:43 AM
Leftoverdj, You can write all over one with one of the carbide tipped vibrating engravers, they run around $15.


07-25-2005, 09:58 AM
I was able to open a .430 die to .431 in short order using a metal rod and wet/dry sandpaper. The numbnuts at the auto parts store had no idea what I was talking about when I asked for some valve grinding compound. They showed me rubbing compound. To mark the die I had to use an arcing pencil I made in junior high shop class.


07-25-2005, 04:51 PM
Would the same method work for opening up a Lyman sizer from .430" to .431"?


07-27-2005, 01:58 AM
Would the same method work for opening up a Lyman sizer from .430" to .431"?




07-28-2005, 11:12 PM
I tried both methods and had better luck with DJs way. Opemed it up .001" in about 1 minute working time. It ended up more round then it was bfore starting. Jay