Size to have mold made to

[JTknives]

I'm getting Mountain Molds make me a mold and I'm loading for the 10mm (40cal). i slugged my boar and its right at .401. i have read that i need to shoot lead that is .001 larger then my boar. so would i have the As-cast Bullet Diameter made to .402 or something else. also this is a gas checked boolit design. do boolits shrink or expand or both. just trying to get everything dialed in before i put in my order. i would hate to order to small but also i down want to have to do much sizing. thanks

[geargnasher]

What alloy? Are you going to heat-treat, water-quench, or air cool? What kind of sizing machine do you use? What weight boolit and how many grooves? Why are you ordering a custom mould before you even know how it shoots lead? Why don't you get the gun doped-out with a $19 Lee two-cavity so you will know what it likes before dropping the cash for a custom-made unit?

Just food for thought, seems you're getting the cart before the horse to me.

Gear

[JTknives]

just using WW and going to air cool and maybe heat treat. its a 200gr WFN with 2 (maybe 1) lube grooves and a gas check. I need a 200gr WFN and can not find one in .401 so i have talked with Blammer, ken as well as thx and thy like the design. just wanted to see what other peoples experience with MM has been. i shoot the 200gr hard cast loads done by Double Tap ammo and my gun loves them. its basically the same design with out the crimp groove and a slightly smaller meplat

[geargnasher]

Do you think they'll feed?

My advice, based on my particular .40, is get a mould that drops WW at .4025", that way you can size to .402 and still get a good seal in the lube/sizer, buuuuut.........What size are the DT boolits? If your gun likes them, you might go with that size, but then again, that's a harder alloy than you're talking about using. IME boolit hardness makes big differences in the way a .40 shoots.

Gear

[Blammer]

the old saying, "it's easier to size them down that up" comes to mind. :)

[RobS]

Dan at MM does a great job with his molds. If you plan on using WW alloy then make sure to mark/check the box when designing your bullet. All five molds I have had from him are either right at designed diameter or .0005 larger. That doesn't mean that every mold will be prefect and he does have a +/- on his work. I would go a bit over and size them down just in case...........that is what I did as a piece of mind. However, since you are planning on shooting a GC design you'll probably be ok at setting the design perimeters at .402 as the GC will for sure be at .402 should you be using a sizing die at that specified diameter anyway.

As to meplat and nose dimensions, if you are making an exact copy of what works for gun currently I wouldn't worry.

[mooman76]

In the case of cast boolits, better a little too big rather than a little too small, especially if you are going to size anyway.

[MtGun44]

+1 on Blammer

[JSnover]

You will get a very well made mold from MM, just make sure you know what you want and give him as much information as you can.