Converting a mold to plain base

[blixen]

I've got a Lee "SMLE" 185gr. gas check mold that I polished out to .315. It works very well with my big-throated Arg. Mauser. But now is too big for even .311 gas checks.

I'm shooting it checkless with mouse loads (5-6 grains of Red Dot). Lotsa fun.

It gives me pretty good groups without gas checks. But I'm thinking that if I make it a truly a plain-based mold by taking out the gas check groove, it will shoot even better.

Question: What's the best way to open the base? And would it make much difference?

Any guidance appreciated.

[country gent]

The most accurate way would be to set it up in a mill indicate the cavity to zero and bore it out with a boring head and small boring bar working slowly and carefully. the next best way would be to purchase a reamer to match the actual size of the mould and in a square drill press chuck the reamer and let the mould float to center turning the chuck by hand and feeding down to a set stop. Next is the reamer and clamping mould in a vise and just hand turning feeding with a tap handle. Last would be a sharp knife or 3 cornered scrapper and working it by hand. If its a single cavity and a larger lathe is available the boring can be done in a 4 jaw if the handles can "swing the full fotation. When doing the boring way I like to ink the cavities so I can easily see the first light touch of the boring bars cutting.

[AbitNutz]

I would chicken out and send it to Eric at Hollow Point Mold Service and have him do it.

[dkf]

I always put it on the mill, indicate each cavity separately and bore out the step in the shank for the gas check. Takes longer but you get the best result that way.

[robg]

Had an old Lee mold with a bevel base I didn't like and being lazy I just used a case chamfer tool to remove the bevel ,just cut the base a little at a time,still has a little of the bevel then a full width base .works for me but if I'd messed up it was not going to break my heart.

[Walter Laich]

I would chicken out and send it to Eric at Hollow Point Mold Service and have him do it.
same here--he's a master

[JonB_in_Glencoe]

This is a interesting read
http://castboolits.gunloads.com/showthread.php?284078-Lee-C312-155-2R-plain-base-conversion

[mrrch]

Careful and steady with a dremel is what I would try following by some lapping.

[gwpercle]

One member said he used the small sharp blade of his pen knife to slowly and carefully remove the ledge. I would have ruined a mould if I had attempted that. I know for sure I would have destroyed it with a Dremel Tool....those things just get away from me and eat up everything.
Maybe an Exacto knife might work better.
Gary

[dubber123]

One member said he used the small sharp blade of his pen knife to slowly and carefully remove the ledge. I would have ruined a mould if I had attempted that. I know for sure I would have destroyed it with a Dremel Tool....those things just get away from me and eat up everything.
Maybe an Exacto knife might work better.
Gary

I de-bevel based my LEE .40 mold with a razor blade, it came out perfect. My neighbor got excited by this and tried it with his. End result: Junk. He is a ham-fisted little monkey though.

[Tackleberry41]

It world depend largely on the mold. Aluminum is pretty easy to work with, a knife will work. Iron or brass will require different tools.

[Shiloh]

Buckshot has done a couple for me.

Shiloh

[blixen]

Had an old Lee mold with a bevel base I didn't like and being lazy I just used a case chamfer tool to remove the bevel ,just cut the base a little at a time,still has a little of the bevel then a full width base .works for me but if I'd messed up it was not going to break my heart.

This is my kind of approach! It's aluminum + Lee ($20) + old = I'll go for it. If I blow it, I'll write it off to education. Thanks everyone for the info.

[EDG]

Put it in a 4 jaw chuck and dial it in. Then bore the base out to any size and depth you want.