Sizing question

[jgh4445]

OK, Brand new to cast boolits, but have been casting round balls for several years. Now about this sizing stuff. When is it necessary to size the boolit you cast? I read that you have to have a "lubra-sizer" and lube to run the bullet thru, complete with sizing die, and then again, I read where you can just tumble lube a boolit and not worry about running it thru a sizing die. What makes one correct and not the other. Terribly confused here.

[grumpy one]

When is it necessary to size the boolit you cast? I read that you have to have a "lubra-sizer" and lube to run the bullet thru, complete with sizing die, and then again, I read where you can just tumble lube a boolit and not worry about running it thru a sizing die. What makes one correct and not the other. Terribly confused here.

You have to end up with a bullet that will be gripped well by the rifling, and will seal well the whole way around, both on the bore and on the grooves. Sometimes that can be achieved with soft bullets and letting them get forged to size by the gas pressure (obturation) but more often if they don't fit they leak, and if they leak they gas cut due to the hot gas leaking past them at hypersonic velocities.

Often a slightly oversize bullet can be sized by the barrel itself, as it enters the rifling. This is part of the reason you'll usually find a bullet that is .001 to .002" oversize will turn out to shoot better than one that is either smaller or larger. Occasionally the best results will come if the bullet is exactly the same size as the groove diameter, but that usually requires a very high quality barrel.

So, how do you get your bullets to be just the size you want? You may happen to buy a mould that casts them just the right size, or you may lap a mould to give that just-right size. However it may be more practical to just size the bullets down to the required diameter - especially if you want to use the same mould for several firearms, since the required diameter is likely to be different for each of them.

Whether or not you need to size your cast bullets, you will certainly need to lubricate them (unless you are shooting paper-patched, but that is a specialised practice). The lubricant does several things, and there is some controversy about the whole subject, but there is plenty of evidence that unlubricated lead-alloy bullets will almost inevitably cause lead to adhere to the inside of the barrel, with negative effects on accuracy.

Lubricating your bullets can be done in several ways, all of which can work satisfactorily. However most people use lubrisizers, because this sizes the bullets and lubricates them simultaneously, to pretty high accuracy standards, with one simple operation. With most lubrisizers you can also change the diameter in less than a minute, and continue work with scarcely any interruption.

So, a lubrisizer is a way to do two necessary jobs well, with a minimum of fuss. There are other ways both to size and to lubricate, so a lubrisizer is not the only way to get the job done.

[runfiverun]

its what will fit your chamber be it rifle or pistol
rifles are different in the way you want to size , you try to fit the lands and grooves as tight as possible.
in revolvers you have that gap to jump
and in auto-loaders you have to get the bullet from the mag to the chamber

with all of these , different lubes and alloys also make a difference
if you are new to all this pick one rifle, pistol, whatever and concentrate on making that one
shoot try different stuff you will learn alot about what is happening with the others to some extent
it is all really not much different than cast vs jacketed vs swaged vs patched

keep reading here and search some of the old stuff.

i wish this existed when i started it would have saved a little grey in the beard

runfiverun

[jgh4445]

Thanks guys. This is beginning to make more sense to me.

[DLCTEX]

Lee's tumble lube boolits are micro grooved, so to speak, and are designed to be tumble lubed and loaded as cast. They may or may not work well in your gun depending on the "as cast" size and the dementions of your particular gun. I find they usually work pretty well. Dale

[Leftoverdj]

Lubrisizers size and lubricate in one operation. The simple Lee sizer sizes only. You have to lubricate some other way. I've got both and use both. The sizer is fast, cheap, and does a better job in some cases. The lubing can be a pain in the butt. For pistol bullets under 1000 fps, you can tumble lube with Rooster Jacket or Johnson's Paste Wax and get good results. For higher velocities, you're pretty much stuck with Liquid Alox which is nasty, stinky, sticky stuff. It does its job, though.

With the exception of the very expensive Star, lubrisizers push the bullet down into the sizer and lift it back out sized and lubed. You have to put each bullet in and take it out by hand which really slows things down. Because they push on the nose, they can bend long skinny bullets which the straight through sizers do not. They also need fitted nose punches which is an additional expense or a major nuisance to make up.

Pay your money and take your choice. Both have positives and negatives.