Sizing ?

[desteve811]

I am new to casting and would like to know how do i determine what size to size my cast bullet to? I will be casting only handgun bullets. (357,44, 45) All help is much appreciated.

[Duckdog]

I ususally go .001 over the barrel diameter... .357= .358 etc. I usually try them without sizing first, as most of the time you don't need to size them, unless you mold is dropping them excessively over the intended diameter. I also us a Lee factory crimp die, which is the same diameter as the standard chamber. If the finished round goes through that die, it will chamber.

Good Luck

[mooman76]

First thing you need to do is slug the barrels ofyour guns to find out what size they are. All guns run slightly different sizes. Just because a guns is disigned to use a .451 bullet does not mean the barrel is that size. You slug a barrel by running a lead(perferably pure or soft) down the barrel and measure it. A round lead ball like they use for muzzle loadrs works real well and some use those lead egg shaped sinkers. On revolvers you need to slug the cyls. too. Then you want your bullets to be .001-.002 over the slug size.
Another thing you can do is shoot them as cast or size to the size they should be. If you get no leading then you are good but if you do, you have lead to clean out. It is est to eventually slug all you guns though for future refference becaus at some point it comes in handy.

[buck1]

I size to the throat diamater of the cylinder. This ensures a centered boolit . The forcing cone in the bbl will size it to bbl dimater when fired.
This gives a good snug fit all the way, and keeps the fouling down.
Sluging is best , but calipers will get you what you need. Use the largest throat size you get to size to. ...Buck

[runfiverun]

buck 1 has the idea with softer boolits it works better this way,i also measure the inside of a fired case, a 360 boolit to fit your throats don't do a bit of good if you can't chamber it.
now with a harder boolit the boolit going into the throat straight is going to give you better results and it being just over your bbl diameter is a good idea.
i usually start by getting the gun,measure it as much as possible then determine a mold.
then aquire a mold and make a few boolits from it and measure those then i worry about a sizer, again a 360 sizr won't do much good for a 359 sized boolit.
then decide which route to take [harder alloy,open the throats some etc...]

[44man]

You still have the worry that a mold you buy will cast boolits large enough so you can make them fit.

[desteve811]

I see how to safetly slug a barrel for a semi-auto pistol (removable barrel) but how would i slug a barrel for my revolvers?

[masscaster]

Hi desteve811,
Welcome aboard!
I'd suggest slugging the bore's to ensure barrel & groove diameter. Then purchase a 100 of these from someone and shoot them at that bore diameter. If all goes well, then purchase your moulds and alloys, sizing dies etc. for those guns. Then once your rolling you can experiment with other boolit types, sizes, lubes, targets(lol), and most everything else.
Me personally I prefer a 150 gr. Full Wadcutter in the .38/.357 (.358), the 245 gr. SWC Keith in the .44 (.430), and either the 200 gr SWC, or 230 gr. RN in the .45 (.452), depending on the gun.
masscaster

[mooman76]

Revolvers aren't as hard to do as they seem. I avoided it for awhile until I finnally did one and found out they aren't as hard to do as they seem. Use something to start the slug that won't damage the crown. I like to use a plastic mallet. Once started it get easier and you can hol the gun on a bench with some rags under it or hold it free hand. I use a pistol cleaning rod with tape wrapped around it in a few places. Lightly oil your barrel before you start. It may help to remove your cyl. before you start.

[desteve811]

so i want to hit the round ball all the way threw the barrel?

[Ricochet]

Usually you can push it with the rod after you get it started. You want to note tight or loose places in the barrel. They can explain problems with a barrel you just can't get to shoot well, or just can't get to stop leading or fouling.

[mooman76]

Keep taping until it forms the barrel and is loose enough to push through. Sort of like loading a muzzle loader.

[desteve811]

I see, Thanks guys!

[watkibe]

The one-size-fits-all conventional wisdom is to size cast bullets 0.001" over the nominal jacketed bullet size. That often makes a good starting point for a beginner, but there is plenty you can do (as you can see posted above) to make sure the bullet is a exact custom fit to your gun. Still, this is all theory, which your gun may not have read about. The proof is always in what size bullet your gun actually shoots best. The theories only point you to what usually works most of the time.
One thing to make sure about is the true size of jacketed bullets for your cartridge. It doesn't always make sense. For instance, my 223 takes bullets that are 0.224, and you can buy jacketed bullets that measure 0.223, 0.224, and 0.227. You can find out the true size from reloading books like Cartridges of the World, and from the websites of bullet makers.

[Zbench]

This is a timely thread as I slugged all my 9mm/.357 barrels today. I found a few surprises. Perhaps the biggest was that my 92F Beretta slugged at .357 as did my P230 Sig .380 ACP

All the others to include a P226, P239 and G33 were dead nuts on at .356

I had been sizing my boolits to .357...no wonder the Beretta and P230 shot like crap. I will need to beagle out my .380 mould some as it drops at just .357.

As to technique, I think that the notion of being able to push the slug once it is conformed to the barrel is a pipe dream, at least in my experience. Here is what I typically do.

Clean the barrel really well and leave a light coat of oil in the barrel.

Put the barrel on the bench and make sure the crown is well padded. I use a couple of pieces of cardboard and about 1/4" stack of cleaning patches

Oil the slug and put it in the barrel chamber.

Take a drift and start tapping it. I cut a 6" piece of brass rod that was 3/8" and then turned it down to .341" in my lathe.

With the barrel upright and the brass drift touching the bullet base, keep tapping it with a light hammer. Once it gets started it will move through the bore pretty easy, but you can't push it...at least I can't.

Keep looking at how far the boolit is from the end of the barrel. When it is about to emerge, take the barrel and hold it in your hand and with the drift still in the barrel, take some light taps until the bullet pops out. I usually hold it at a 45 degree angle to the bench, and have a couple of rags for it to shoot into it.

Once it's out, dry it off and measure with an accurate micrometer. I bought one of those new Mitutoyo's which goes out to 5 decimal places which is a sick amount of accuracy just for this purpose.

As long as your barrel has an even number of grooves, you just need to measure across two that oppose each other.

Hope this helps.

Pete

[Bret4207]

You can slug it, you can shoot soft boolits through at low speed and catch them in something like a large box of rags, you can get a variety of sized boolits and see which works best. While I've slugged a bunch of guns the best way to know for sure what the right size is comes from shooting. The EASIEST way I know is to take a fired case and measure the ID of the case mouth and size to that diameter, but even then you may run into the odd duck that wants a particular design .001 smaller for some reason. IME each boolit design in each gun may require a different size for best results and that can vary with alloy too. IOW- no easy answers!

The barrel is the ultimate sizer and only through experimental shooting will you determine the "best" size for a particular boolit and alloy.

Edit- That sounds terribly difficult on reflection. Just measure the ID of the case mouth and start there. That's about as big a boolit as you'll be able to fit and should work.