Sizing die effect?

[hanover67]

I'm at the entry portal of the bullet casting world, reading, acqiring equipment and spending too much time on this website...My question is about sizing dies. If my bullets drop from the mold too big in diameter, I assume that a smaller sizing die will "squeeze" them down. But what if the bullets are too small? Will running them through a larger die (on an RCBS sizer/lube) increase the diameter?

I have a Colt Army Special in .32-20. The bore slugs at .312 and I have a .3118 Lyman mold. I've been using 115gr commercially cast bullets which measure .314, which are a tight fit in the cylinder throats and getting poor accuracy. If the bullets drop at .311 will they bump up in a larger sizing die, or do I need a bigger mold?

[williamwaco]

Bigger mold.

Search here for mold lapping and mold beagle

[ku4hx]

Generally sizing reduces bullet diameter and pushing a too small bullet through a larger diameter die is not generally going to cause the boolits to swell in diameter. I guess it could work if the boolit was soft enough and you could exert enough compression force on it to make it swell to fit the die. There are better approaches.

You can bump the boolit lightly with a hammer to cause it to swell, but I for one have just never been able to do that well. Or you can hone your mold to have it cast larger boolits. Or you can adjust your alloy to naturally cast larger boolits maybe.

Basically I'm a simple person with simple solutions. If a boolit casts too small I try a different alloy first. After that I just get a more suitable mold.

The other methods will be addressed by other respondents so be sure and watch this thread.

[sqlbullet]

The right solution is to enlarge your mold or get a larger casting mold.

Several custom mold makers here guarantee there molds as -0 to +.002. That may be an option if you can't enlarge your mold.

I would be surprised if that mold doesn't drop at least .312.

[Char-Gar]

If you have a barrel with groove diameter of .312 and cylinder throats of .314, you need a bullet that will be .313 - .314. It would take more pressure than you want, or a softer bullet than you want to slug a .311 bullet up to .313 - .314.

You are better off getting a correct size mold to start with.

Before you get too far into this, figure out why your commercial bullets were doing poorly for you. The numbers sound right, so what is the problem?

[Maven]

hanover67, Before thinking about a new mold, which isn't a bad idea btw, let me ask how that gun shoots with jacketed bullets. Moreover, what kind of load are you using and can that be part of the problem? Is there bore leading with those commercial .314" CB's? Would it help to tumble lube them in something like Lee Liquid Alox? Lastly, if you were to push 2 or 3 of the .314" CB through each cylinder throat and then measure them with a micrometer, what dimension would they be? Is it possible that all you need is a sizing die that would bring those CB's to that dimension? Lastly, a typical Lyman/RCBS can bump up a cast bullet, but you'll need some way to make the process repeatable and that's not so simple. Whether you can reliably bump up .311" CB -> .314" (?) may be worth looking into though v. purchasing a new mold.

[hanover67]

Arghh! I was afraid of this...I read Ken Waters' article on the .32-20 revolver load and noted he had a lot of trouble getting consistant velocities, so I'm anticipating a long trial and error process. I haven't tried jacketed bullets yet and the only others I've used are the Hornady 90gr LSWC and some .32 caliber bullets a friend cast for me that are about 115gr LSWC gas checks. The Hornadys are .314 and the CBs are .314 at the driving band and .312 at the gas check end. But, they have been the most accurate to date, even though they had wrinkles and Lee tumble lube alox (messy). And, the bore of my gun's barrel is really rough.

Waters used the same mold I have, Lyman 3118, so I'll try it. But, given the comments here, it looks like I'll need a bigger mold. We'll see how bullets drop when I get around to casting. Maybe they will be big enough. It looks like trying to increase a bullet's diameter is not workable. Many thanks for the advice.

[462]

Welcome, Hanover67.

Beagle is a Cast Boolits member and the author of this article. Thanks to him "beagling" is quite common. I've "beagled" a number of moulds, including one just last week.

By the way, it is reversible, so fear not.

[mainiac]

Arghh! I was afraid of this...I read Ken Waters' article on the .32-20 revolver load and noted he had a lot of trouble getting consistant velocities, so I'm anticipating a long trial and error process. I haven't tried jacketed bullets yet and the only others I've used are the Hornady 90gr LSWC and some .32 caliber bullets a friend cast for me that are about 115gr LSWC gas checks. The Hornadys are .314 and the CBs are .314 at the driving band and .312 at the gas check end. But, they have been the most accurate to date, even though they had wrinkles and Lee tumble lube alox (messy). And, the bore of my gun's barrel is really rough.

Waters used the same mold I have, Lyman 3118, so I'll try it. But, given the comments here, it looks like I'll need a bigger mold. We'll see how bullets drop when I get around to casting. Maybe they will be big enough. It looks like trying to increase a bullet's diameter is not workable. Many thanks for the advice.
If ya do need a bigger boolit, you might want to look at the rcbs98swc mold. Thats what i use in my 32-20,32 magnum etc. My mold drops a ww alloyed boolit@.316 diameter,,plenty big enough to size with!BTW, in case ya didnt know,this boolit is splendidly accurate,to boot!