Bumping up a bullet sizing die?

[PACKIN' PLASTIC]

I need a .248 sizing die

How hard would it be to take a cheap lee .243 die and polish out 5/1000 of material?

I’m thinking a bore mop covered in wet honing or buffing compound and attached to a drill.

Think it would work?


PP

[Maven]

PP, That method wouldn't give you a concentric die. For very little money and no effort on your part, have Buckshot or Lee Precision make one for you. It WILL be .248" and concentric too.

[Scrounger]

It's doable. Buckshot has instructions published on our sister site, Castpics. It pertains to Lyman type dies but is equally applicable to Lee Sizer Dies. With them, the part about plungers doesn't apply.

How to hone a size die
by 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.

[cabezaverde]

For those of you who have done this, how much "rolling" does it take to remove .001 or so?

[454PB]

I use a lathe to open them up. Lee dies are fairly soft, and don't take long to open up.

[dk17hmr]

I use valve grinding compound covered bullets. The first one I did .309 LEE sizer, I wasnt thinkin right and ran 45-50 bullets through it before I checked the size....I now have a .3125 sizer, my goal was .3105. If you do this run 5 or so than clean the die good run a none compound bullet through to check the size. Do that until you get where you want to be, or a little less. Say .0005 less than get some 600 grit paper on a rod and polish it smooth.

If you leave the sizer opened up with just valve grind compound it will have vertical scratches in it.

[Bret4207]

I took a Lee .329 sizer to .332+ in 400 rolls using 220 grit if I recall correctly. I ran the rod laterally and flopped ends a couple times too. You can finish the process by coating a few boolits in grit, even Bon Ami will work, to polish it out. Not hard at all.

[yondering]

I just use a strip of emery cloth wrapped around a steel rod, in a cordless drill. Takes less than 5 minutes to set it all up and open the die up a few thousands. Last time, I just used 240 grit, dry, so the grit would break down finer and polish the surface. Worked really well, boolits through that die have a mirror surface on them. Of course, you could probably open up the die with a screwdriver and get a better finish than how they come from Lee.

[Buckshot]

................In the Lee type push through dies, the actual sizing portion is less then 0.100" wide so it doesnt take a lot of effort to open one up. Also, there isn't much parallel area to act as a guide, so the possibility of 'Egging' the sizer is greater the larger you want to go.

..............Buckshot