Doomed even before I get started ?

[pt4u2nv]

Just bought a .40 caliber Taurus semi and wanted to shoot cast in it from the start. Appears I may be in for quite a problem as when I slugged the bore and measured ( with a micrometer ) it showed the bore to be .401 to .4017. My boolits (RCBS 9MM-124-CN) I have been using in 2 other 40's I cast for are at .4013 to .4019. Not near big enough for use in the new gun. My other 2 40's bores slugged at .4001 to .4005 and .3984 to .3996 I looked for a .402 sizing die and cannot locate one which will probably not work anyway since my boolits are not big enough to size at .402 from the start. Comments and help for a solution would be great. I tried a few things to get the boolits to drop bigger to no avail.

[runfiverun]

you could lap the mold a thou easily.
a 402 sizer is no big deal either,you can lap the 401 out to 402 out at home.

[pt4u2nv]

you could lap the mold a thou easily.
a 402 sizer is no big deal either,you can lap the 401 out to 402 out at home.

OK.... easy for you to say.LOL How do "I" lap the mold , it is a steel RCBS mold. And what do I do to the sizer ? Is this normal for a 40 barrel to be this big ? I am fairly new to this type of problem so excuse my ignorance.

[fecmech]

Just "Beagle "your mold. You can easily pick up.001-.002".
http://www.castpics.net/subsite2/HowTo/Beagling.pdf

[Guesser]

I understood all the references to 40; what has me confused is the correlation of the RCBS mold designation and it's correlation to 40. 9MM-124-CN=40? How does that work?

[Wayne Smith]

Beagling a mold is relatively easy and equally easy to reverse. If you don't want to modify a sizer you can PM Buckshot and he will make a die that will size your alloy perfectly if you tell him the content of your alloy.

[pt4u2nv]

I understood all the references to 40; what has me confused is the correlation of the RCBS mold designation and it's correlation to 40. 9MM-124-CN=40? How does that work?

Sorry ,wrong mold , it was a RCBS 10MM-170-SWC . Been working back and forth between the 2 and got discombobulated.

[snuffy]

What alloy are you dropping in that mold? A bit more antimony and tin should cast a bigger boolit. It could also be a bit harder which wouldn't hurt anything for use in a forty. Harder alloys generally cast bigger.

As for honing a die, I use a strip of Emory paper slipped into a cut in a hardwood dowel. Then spin that in the die with a drill motor, while moving back and forth or up and down the bore. Never have done a RCBS sizer die, but Lyman's are pretty hard, it takes a while to remove .001. You will need to change the E paper to replace the worn out grit. I use 320 grit, that's all I have, it is what most use to finish with.

Some will say to use the above method, but to simply roll the sizer against your leg, instead of using a drill. That would take an eternity, result in sore hands and leg, and lead to invention of a few new cuss words.

[runfiverun]

add a little oil to snuffy's dowell and paper.
you can beagle out the mold with 3m flue tape [they have or can get it at the local ace]
it gives you about .002 on the one side.
lapping a mold is pretty easy,there is a sticky here that goes into good detail of what you are doing.
it's called lee menting and is in the sticky section.

[1Shirt]

Yep, go with Beagling, cause it just works!
1Shirt!

[pt4u2nv]

I have beagled molds before and it does work I agree. I will try that 1st. Sizing / lubeing will be the next issue so I guess I will either get another sizer made or lap the one out I have. I quess i am concerned lapping out my existing sizer will mess with the sizes I need for the 2 other 40's I own.

Is it normal to have a 40 barrel this large ?