best way to open Lee sizer up .0025

[Wayne S]

I have a .308 Lee sizer that I need opened up to .3105. What is the best way to insure perfect roundness.
I have;
1/4" steel rods,
400 & 600 grit wet sand paper
Very fine valve polishing compound
a have .312 J bullets as well as .313 cast bullets
Method.
A. coat rod & inside of die with valve compound and roll back & forth on a flat surface
B. wrap sand paper around rod and roll
C. coat "J " or cast bullets with compound and run through sizer die

Thank you

[btroj]

Go with B. Seems to be a tried and true method. The one I did worked quite well and seems to be round as far as I can tell.

[Kraschenbirn]

Never tried opening up a Lee but have "adjusted" three or four Lyman sizer dies using wooden dowel wrapped with emery paper, applying final polish with extra fine lapping compound. Best advice I can offer is to go slow, checking your progress often.

Bill

[Maven]

Wayne, Take a look at Buckshot's article in CASTPICS: http://www.castpics.net/subsite2/HowTo/How%20to%20Hone%20a%20Size%20Die.pdf

[ph4570]

Option C works the easiest for me on the star. Seems like it should be good for the Lee as well. I have used option B but C goes faster in my experience. I use three grit sizes -- 220, 320 and 400, as I recall.

[wmitty]

Wayne S

I've had really good luck by rolling a soft cast boolet in the lapping compond after pushing it thru the die to allow starting the lapping action at the initial diameter. I used oversize Hornady swaged bullets (.40 cal) to open up a .358" Lee to .367" for paper patching a .375 boolet. I ran the .40's thru the the .375 die and then thru the .358" die; then placed them on their sides on a flat granite plate and imbedded the lapping compound in them by rolling back and forth. Also opened a .308 Lee to .319 using boolets with lapping compound. The alloy was air cooled w.w. and die wound up within .0006" of being round.

[DLCTEX]

I have opened up a number of Lyman and RCBS dies using the wooden dowel and abrasive cloth and rolling the die as Buckshot suggested.