Lubrisizer die lapping (would like some advice)

[ozymandias]

I've got a .378 RCBS die that I'd like to open up to .379. I'd be interested in how this is best done. I don't own a lathe or machine tools, so I'm wondering what other methods there are that wouldn't result in a out-of-round die. Thanks.

[osage]

I have not lapped any dies but Lee so I don't know if RCBS's are made of a harder metal. I wrapped emery paper around a split rod, oiled it, inserted into the die. Then rolled it back and forth on my leg. Old jeans as they will get oily. Stopped often and size a boolit to check progress.

[osage]

Ok I found another thread that shows on the Castpics site you can get article on how to hone a die. You will find a link to that site at the bottom of the page.

[chboats]

I use a steel rod or long bolt that will fit through the die(largest possible) and lapping compound 220, 320 and 600 grit. Put lapping compound on the rod or bolt and put through the die. Start rolling. You will be taking of so little that by rotating the roll start point every few passes the roundness can be maintained.
The most I have taken off this way is .002 which will take a while but you end up with a round smooth die

Carl

[tactikel]

Its really easy, I lapped a .308 die to .3095 in 20 min. I used 600 grit garnet paper lubed with oil wrapped around a phillips screwdriver. Rolled across an old bath towel, exposing fresh grit and adding oil as needed. I finished with some pumice powder on a bore mop soaked in oil (of the same caliber) chucked in a drill driver. Run it back and forth for a few minutes. The die is so smooth and fits my bore perfectly.

[StarMetal]

I used the different grit sizes automotive sanding papers. What you want to do is clean the die thoroughly and run a slug through and check the size. Remember the old adage measure twice cut once. If you make it too larger you can't put the metal back. I use the finest grit for the final lapping and then polish with jewelers rouge.

When finish, again, make sure you clean the grit out of the lube holes...don't want that in your lube, on your bullet, and in your barrel. Make a new plunger. If you're not going a lot you don't have to worry about the larger tapered leade in.

[DLCTEX]

I just reamed a 457 die to 459 by using a 7/16 dowel, sawed a split about 1" into the end and used cloth backed abrasive torn to a 1" width and just long enough to place one end in the split and wrap around the dowel once. It was necessary to sand the dowel while turning it in my drill so that there was a snug fit in the die. Using the drill I easily opened it to 458, then spent a little more time creeping up to 459. I changed abrasive several times but at the end left the worn cloth in to get the last little bit. the worn cloth left a very smooth surface. I wondered if the .002 gap of the rod to die fit would leak lube, but with a good warm lube ( it was a warm day) it flowed with little pressure and no leaks.