View Full Version : do you need to size boolits?

07-21-2010, 10:00 AM
hey guys im new to casting and reloading cast boolits. do i need to size my bullets? ive got a lee 500 grain 2 cavity mold thats .459 dia. i havent checked my loads with calipers yet though cause i cant find them. ive got a lee classic loader that you cant really use a sizing die on. is it necessary to size them?

07-21-2010, 10:13 AM
It's gonna depend on a lot of factors. The short answer is "maybe". In any event, you will definately need to lube. Unsized bullets may shoot fine in your gun and not in someone elses. Sized bullets may shoot better, or may not. How's all this for a "non-answer".

07-21-2010, 10:16 AM
yeah i definately will be lubing them. i dont want to buy a press just so i can size bullets though.

07-21-2010, 10:20 AM
the very short answer is NO....if the boolit diameter as cast is right for your weapon, then don't size. Although if you use a gas check you will have to put it on by hand, and you will have to pan lub the boolit. Pan lubing can be messy which is why alot of guys don't bother and just go ahead an use the sizer.

The recommendations I have read about sizing is to size the minimum required. So if that boolit is the right diameter for your application ( say .001 or .002 over grove diameter) then I would recommend trying pan lubing and firing them as cast.

07-21-2010, 03:37 PM
Me, personally? Yes. I size everything I shoot.

You don't give us any real information on your application, so it's impossible to even hazard a guess as to whether or not YOU need to.


07-21-2010, 03:45 PM
Try and see. If they will chamber OK, don't lead and provide accuracy acceptable to your needs, then no, you don't need to.

In semi-auto's there can be reliability issues if the bullets aren't a uniform size. Since molds rarely cast round bullets (they are usually .001" bigger on one axis than another) there may be accuracy issues as well.

I don't size my 175gr Lee .401 TL bullet. I load these for personal defense drills, usually at no more than 25' distance, with the rule that if your group is smaller than 4" you need to shoot faster. They are dead reliable and don't lead, so sizing would be a wasted step.

I do size my 205 Gr .401 from my mountain mold. These are my long range accuracy bullets for my 10mm when I am shooting smallest group to determine who is buying the milkshakes after the range outing. I want them all very uniform, and since I seat them a little longer, the uniformity ensures reliability too. Very important since these projectiles are also used in my special formula bear repellent.

So, to summarize, if the loaded round will chamber easily and properly in your gun, then, no you don't "need" to size for safety or weapon function reasons. You may still want to for uniformity reasons.

07-21-2010, 09:32 PM
I've done pan lubing with thousands of .44, .45, .357 and 9mm then straight to the Dillon 550. Maybe I'm just not good enough shooter to recognize the difference but I have two Stars and a SAECO lubrisizers that are a lot cleaner and faster to work with, so I do size very lightly but it's for the convenience more than necessity. I even run the .357 cast boolits through a .358 sizer to run in my 9mm. There is a bit of a smear of lube on the boolit when I do this but I just wipe them off and continue to load them.


07-21-2010, 10:08 PM
I size everything, without exception.

The reason is that I'm looking for variables that affect accuracy and performance. The more variables I can eliminate, the closer I can get and maintain "pet loads."

Size of the boolit and the lube used are two variables that are easy to control. Get yourself a $20 C-press from Lee and a $15 push-through sizer from Lee and go to town.

For lube, you have several options. You can tumble lube (http://castboolits.gunloads.com/showthread.php?t=67654http://castboolits.gunloads.com/showthread.php?t=67654) or you can pain-lube, which a lot of folks do. I personally do not like pain-lubing (aka pan-lubing by those who are skilled at it, paIn-lubing for casters like me :)). There are lots of different ways to pain-lube, all of which when done correctly will generate stellar results.

But as far as sizing? Again, I size everything I cast and load.


07-21-2010, 10:58 PM
Just a guess since like stated you didn't give much info, but the bullet you are talking about is for a big gun probably 45-70 and they tend to like the big bullets like 459. Lube and load one and see if it chambers ok. It's recomended you slug your bore to see what size is best.

07-21-2010, 11:03 PM
I don't size my 38 spl boolits, I do size my 44 mag boolits, I do size my .30cal boolits , and I don't size my .40 S&W boolits.:bigsmyl2:

chris in va
07-21-2010, 11:35 PM
The tumble lube 45acp boolits drop at .453 so I don't size them. The 358 9mm boolits drop at .362, so I do have to size those.

max it
08-04-2010, 12:27 PM
HI Guys, Rather that start another thread, this one addresses my issue pretty well. So if you still have your ears on here goes:

I drop at .359 (mihec mold)
I shoot .38/.357's at .358 which sizer I have (two actually).
I shoot mostly 9mm, my barrel is .3545, and I have been sizing to .356.

However I have been reading that sizing too much isnt good for accuracy.

SO should I get a .357 sizing die? I see Midway has them now.

opinions, ideas, comments much appreciated.


08-04-2010, 12:49 PM
If they shoot well out of you 9mm, then no need. The reason not to size more than .002 or .003" is that is you try to size more than this generally, the base will suffer and the lead will be pushed doen from the sides and base unevenly and will overhang like a skirt around the bottom. This is generally bad for accuracy. I am sizing a .312 down to .309 with no problems right now and it works fine for my needs.

One thinig I have found in this world of cast bullets is just try it. As long as accuracy is the issue and not something dangerous like pressure, give it a try for 10 or so rounds. You may be cleaning lead out of your barrel or be happily surprised, either way you are learning.

82nd airborne
08-04-2010, 01:19 PM
yeah i definately will be lubing them. i dont want to buy a press just so i can size bullets though.

How are you going to load the boolits if you dont have a press to size them? it will be dang difficult loading them without a press.

max it
08-04-2010, 07:08 PM
Good common sense, I guess I will leave well enough alone.
As each die is $20. and I am getting a little tired of constant stuff to buy.
However since I have two .358's I might as well offer to swap on the sell/swap forum.
Anyway much obliged,


08-04-2010, 07:33 PM
I size everything. But like everything else in loading, it's best that you try both ways and see which is more accurate in your gun.

08-06-2010, 08:36 AM
In semi-auto's there can be reliability issues if the bullets aren't a uniform size. Since molds rarely cast round bullets (they are usually .001" bigger on one axis than another) there may be accuracy issues as well.

I find it hard to believe that a bullet shoved down a round barrel with 16 to 60 thousand psi will exit in any shape BUT round, now mater how it starts out. If the bore isnt round than any bullet sent down it wont be either.