.40 caliber bullet mold issue

[Greg G]

Hey guys. I bought a custom .40 caliber mold recently. I ordered it at .402", the tolerance for the mold was -0 to +.002". With wheel weight it drops .404" - .405" according to my micrometer. The gun has a Bar-Sto barrel in it that is advertised at .400" groove, and it has a tighter chamber than the stock barrel. I had planned to size to .401". Sizing to .401" is too much sizing for bullets out of this mold. It increases the bearing length a lot on the front of the bullet and I don't think it would even chamber.

I kind of know the answer to this already, but I'm stuck aren't I?

[bosterr]

Since you mention the +.002 tolerance I assume you have an Accurate Mold? I have quite a few of Tom's molds and I order to drop at "size diameter", they will automatically come out at .002 larger. I've even ordered a mold at .001 smaller than "size to" diameter so that I'm only sizing down .001 so that when I size nose first with my Star I prevent any "skirt" on the bullet base. Did you slug your barrel? Did you try the plunk test with a loaded round? It's possible your barrel isn't quite what the manufacturer says the dimensions will be. I know this from past experience. I know it's not what you want to hear, but DougGuy has been known to work wonders on situations like this.

[Tackleberry41]

Try a couple and see. Never know, might not be to much sizing down.

[rintinglen]

Load up a couple of dummies and give them the plunk test. If that works, put them in the magazine and cycle them through the action. If that works, you are good to go. I have sized boolits a lot more than 3 thousandths with useful results. I regularly reduce 358-429"s to 350 diameter to use in my 348 Winchester.

Even if they don't work as advertised at first, try seating them a few thousandths deeper, Say .005 and then try again. If that works, it is a simple matter to reduce the charge a tenth or two of a grain. If you stay away from the top end and stick with loads that function the gun but are nearer "Start" than "Do not exceed," you'll be just fine.

[Ed_Shot]

Both my Lyman 401043 and 401654 drop @ .404 ~ .405 from the mold. My alloy is hardball (6-2-92). I use a Lyman 450 to size them to .401 using White Label 2500+ lube. I've shot thousands of them thru my G22 w/LW barrel. Superb performance with zero leading. They are not difficult to size and certainly not deformed by sizing. Yes, I can visually tell that the driving bands are wider after sizing but see no ill effects. Lyman calls for a COAL of 1.125 with the 401043 and I load to 1.130 just to get the boolit shoulder above the rim. Likewise Lyman spec's a COAL of 1.090 for the 401564 and I use 1.100, again to get the shoulder above the rim.

I would not give up too quickly on your mold because it drops fat.....see how it performs.

[Greg G]

Thanks guys. I'll tinker with it and see what happens.