I've entered the world of casting my own bullets and plan on powdercoating using the shake and bake method. My first batch of bullets will be .358 SWC for .38spl/.357mag. Using my micrometer I found that my mold drops bullets that are undersized as most average .3555. I expect the powdercoat to add a few thousandths which should get me up to around .358. Will I still need to resize? In your experience, how much has a single coat of powder added to your bullets?

Thanks for your insight.

The hobby you have entered into is truly a "try and see" venture.

BTW: If it was me I would make the mould drop larger bullets.

Motor

I would open the mold a little or use a different alloy to get proper sized bullets. I size PC bullets with lee sizing dies.

I avoid sizing any cast bullets, PC'd or not, unless I've they won't chamber otherwise.

I did this same thing for a long time but then I started casting for Mosin Nagants and other various size 30ish calibers.

Then I tried powder coating and haven't touched lube since.

Now I have final diameters in mind and do whatever it takes to get there.

My Finnish Mosin Nagants are .3105 to about .3115 and my mould drops around .313" So when I used lube I just shot them as cast. But now with PC they are kinda too big and I only have a .311" size die.

So now I size the bullets to .311" then powder coat them and load them unsized after PC. They are at least as accurate as they were before but now no lube mess.

I powder coat and size all of my 9mms and .38/.357s to .358" This is proving to work great in everything.

Typical semiautomatic 9mms have very generously sized chambers.

Motor

Thanks for the input. The mold is an inexpensive Lee aluminum two-cavity mold. My alloy is approximately 8.75lbs clip-on wheel weights, 1.25 stick-on wheel weights or range scrap(very soft), and a bit of 50/50 solder for some tin. Bullets are properly filling out the mold. Perhaps I should invest in a better mold.

You don't have to buy a "better" mould. Go to the cast bullet forums and learn how to make your Lee mould drop larger bullets.

There are at least 2 different ways. I use foil tape on one of mine. I think this is called beagleing. But I may be wrong.  

Maybe someone will post a hot link to castboolits forum.

Motor

Thank you gentlemen! I'm going to try lapping my mold to open it up a few thousandths to .358.

Let us know how it turns out. I thought about lapping my 501 mould but took the easy way. Lapping should result in a more round bullet although I get excellent results so being a little out of round must not matter much.

The last 2 or 3 Lee moulds I bought have been disappointing. All of our older Lee moulds drop big but these all drop small.

As we all know too well big is easy. It's hard to size up.

Motor

I haven't done any bullet casting yet but I have been reading a lot about it.

I seem to remember reading somewhere that if the molten lead is too hot it causes the bullets to shrink a bit as it cools in the mold.
It said for thinner rifle bullets you need hotter lead so it flows better but for pistol bullets you need it a bit cooler so they won't shrink.

I just started casting. I thought i read that lead composition changes weight and bullet size.

I did this, they're shootable accuracy is ok. Not terribly round out of the mold and the seam is very pronounced, the leading edge of the bearing surface is no longer even so they have to be seated deeper. Process took forever.

I will never do it again. I'll either PC or buy another mold from someone that understands 9mm is not .356"

I have not had this problem.  My .357 and 9mm bullets when powder coated come out to .358 and .356 out of lee 2 cavity moulds.  The only thing i noticed is the pc adds around 4 to 5 grains to the weight.

I just bought some PC on Saturday. Gonna try a batch or two and see where that gets me.