Why do we size?

[Bret4207]

Ok, so I'm stirring the pot. Anyone else out there in cast boolit land have better luck with unsized boolits than sized? I always do. New sizer dies vs. the old Lyman that cut the boolit help, but I still have better luck polishing out a Lee sizer and putting the GC on that way than with the Lyman/RCBS sizers. And yes, I use either the proper top puch for pointy type noses, set loose so it doesn't cock the boolit, or a home made flat faced job that will aloow the boolit to align itself. I'm begining to wonder if the $$ spent on the traditional type sizers is worth it. Too bad I don't have more faith in the Lee Liquid Mule Snot.

[felix]

Actually, any kind of sizing other than 100 percent complete swaging is detrimental. Things really do have to be uniform 100 percent throughout a boolit for a boolit to be the best it can be. We are just making compromised boolits, which is following the spirit of our game as defined during the 1800's. Intentional! ... felix

[BCB]

Trp. Bret,

I shoot everything “as cast” except the 287346 (0.287”±) which I sometimes size to 0.278” in a Lee push though and shoot it from a Model 700 in 270 Winchester cartridge. Otherwise if the bullets require a gascheck, is size only the check to seat it using an RCBS Lube-O-Matic with that Lyman thingy (lack of correct terminology!) that only allows the bullet to enter the sizing die enough to seat the check. I seem to have better luck shooting them “as cast”. But, I don’t shoot the variety of slugs in the variety of weapons that most people on this board shoot. I am an amateur compared to most on this site…BCB

[eka]

This brings up something I have been wondering ever since reading the RCBS Cast Bullet Manual. In this manual it says that for every .001 of sizing results in about an extra inch of group dispersion at 100 yards. It says the bullets must be perfect out of the mould. The book goes on to say that as a manufacturer of mould blocks, they are forced to produce cavities from .001 to .002 inch over nominal barrel dimensions partly because of the different alloys used, but mostly because of tradition. For some reason casters like to size bullets. In another section of the book that deals with heat treating bullets to harden them, it says that sizing the hardened bullets negates most of the benefits reaped from the heating process. The book talks about sizing the bullet with the proper size die without applying lube. Then, heating the bullet to harden it and then running the bullet through an oversize sizer die to lube. In this process it seems like a pain to clean the lube out of the lubrisizer to size. As someone just trying to get my feet on the ground in casting, I would be interested in hearing the experienced casters weigh in on these issues.

[NVcurmudgeon]

I frequently am tempted to pray that RCBS will see the light and quit making their boolit moulds so small. If "every .001 of sizing results in an extra inch of group dispersion at 100 yards," my favorite rifle and load would shoot nearly six inch groups, rather than the less than two inch groups it actuallly delivers.
(I size the Lyman 314299 boolit from its as-cast diameter of .314" to .310".) When I wish to shoot boolits at as-cast diameter, I use sizing dies that do little or no sizing, because I am unwilling to smear lube into the grooves by hand, or make an even bigger mess with the Kake Kutter method. This may be heresy, but if I had to give up the convenience of my Lyman 450 machines, I wouldn't consider cast boolits worth the trouble. All the above is IMO.

[9.3X62AL]

eka--

I read that same passage in the RCBS Manual about "every .001" of size-down = 1" diameteric dispersion", and I would be inclined to say AT MOST "maybe" or "sometimes". My own view is that reduction of .001" in a sizer is FAR preferable to hoping an undersize boolit "slugs up" to fill a dimension it is undersized to fit in the first place. You seldom hear casters--here or elsewhere--bemoan oversize molds.......but there is a cottage industry built up trying to fatten the castings--Beagling, lapping, custom makers, you name it.

To follow on NV's lead, it sure as hell seems like RCBS wants to single-handedly do something about fat molds or "undue" sizing. If their cavities were any more undersized, they might do as paper patch slug molds. One exception--their 6mm mold, which casts at .2455" with Taracorp alloy--otherwise, they are "skinny". A shame, because the RCBS tools are a real delight to cast with otherwise. I have recently found that cooler casting temps (675*-700*) using Taracorp alloy in the RCBS and Lyman blocks gives a little fatter casting, possibly due to less shrinkage contraction from cooling. This fattening isn't dramatic, on the order of .001" in 30-36 caliber castings and .0015" in 40-45 calibers--but it's there. Just another example of the gymnastics that casters go through to get the boolits fat enough.

[Bret4207]

I'm lucky I guess as my RCBS moulds cast at the needed diameter with WW, .311 and .451. I find most Lymans cast as much as .002 undersize. A real shame when you NEED .314+ and can only get .313 or a bit under. Still, it seems a shame to drill the "size before shooting" idea into the noobs heads. I think it was an Al Miller article in an old Handloader that got me to thinking about shooting unsized boolits. I'd been sizing my 311316 in a .312 die because thats what Lyman recommended. I grabbed a handfull of unsized boollits, snaped the GC on and hand lubed them. My previously disappointing 3" groups shrank to the 1-1 1/2" at 75 yard groups I expect these days. I also had a Lyman die that would form an oblong or oval boolit due to a maufacturing defect.

I think too many of us depend on the sizer to "straighten out" our poorly cast boolits. If you take a cruddy looking boolit and run it through the sizer all the flaws are filled with lube and the GC takes care of the gvoid on the edge of the heel. No wonder we get crap accuracy that way. Add in the problem of guys who won't settle for a sizer die that just barely touch the booits sides, but instead insist on seeing the "sizing smear" all aound the boolit and you get problems. Better to advise people to lap out a Lee die to just touch the side of the boolit or better jsut leave a film of lube, rather than "cutting them down". This is not to say that the convenience of a lubrisizer is lost on me. I just think a lot of the throat measuring and worry about obturation would be avoided by trying unsized boolits before jumping to custom sizer dies and throat reamers. Let the rifle throat size the boolit and see if it works first. Obviously there are cases where this will be a complete failure, but I think sizing is another hard and fast rule that needs re-thinking.

[9.3X62AL]

I think you hit the nail on the head, Bret--CONVENIENCE. The luber/sizer squeezes the goop into the grooves pretty neatly, and it is a lot more a "luber" than a "sizer" for me.

[XBT]

I try not to size at all. Most of my cast boolits are run through a slightly oversized die to apply the lube and gas checks (if needed). The limited testing I have done indicates that unsized boolits are nearly always more accurate.

[Maven]

Another reason we size is to make slightly out of round CB's more uniform. With respect to RCBS' argument that every .001" in sizing -> greater target dispersion, that's simply not so if the CB's are sized concentrically. The older H & I dies didn't have a tapered entry and were likely to size unevenly, thus creating greater dispersion. Btw, Buckshot and I (separately) have sized lubed & gas checked CB's down a great deal, from .326" -> .314" in my case, with no diminution in accuracy v. normally sized CB's. RCBS' claim that there should have been an extra 12" of dispersion at 100 yds. just didn't happen. And yes, the results were repeatable. However, it wasn't a joy to reduce the diameter by .012".

[MTWeatherman]

Some moulds may cast bullets too large for a firearm with a tight throat. I have a Taurus revolver with a .357 barrel and a .358 throat. I can't easily chamber the cartridge with most unsized bullets. The bullets drop at over .358 and the cartridge either has to be forced into the chamber or,with some, can't be fully chambered.

However, I suspect that most size their bullets as necessary function of lubing in a lubrisizer. I confess to the same for most bullets. Liquid alox may be convenient...but I dislike lubricant on the bullet nose...it is messy. For that reason alone, I use a .358 lubrisizer die to lubricate already sized oven treated 9mm bullets. I also haven't had good luck with liquid alox at velocities over about 1500 fps.

[Junior1942]

I also haven't had good luck with liquid alox at velocities over about 1500 fps.The trick is to use two coats of LLA. For me, it works fine to 1850 fps in 357 mag and 30-30 using ww alloy.

[StarMetal]

Maven, besides you and Buckshot I've sized down cast bullets to even more drastically smaller diameters then Buckshot or you I'll betand that's .020's in reduction. Buckshot was shocked how my 7mm's sized down to shoot in my 260 performed pretty decent. I've also done some drastic sizing down of various bullets to fit that oddball 8x56R, including jacketed.

I've had mixed results with sized and unsized bullets out of the same gun that I was using. For me some of my best groups have come from sized bullets and that is out of a Lyman luber/sizer. I think there is a point where unsized is too large. I find this especially true in rifles more so then revolvers. I don't mean where too large is too big to fit the throat or to prevent the round from chambering. I've had quite a few 7x57's shoot extremely well with bullets sized to groove diameter. I have a few rifles in 30 caliber and some of them shoot better unsized and other's don't.

For me then, sizing performs two or three tasks and those are: sizes the bullet to the diameter that it performs best at in my particular gun, lubes the bullet conviently, and seats a gascheck if one is used.

I have no doubt that the old untapered sizing dies gave sizing a cast bullet the bad rap it's currently enjoying. If a sizer back then shaved a bullet and particulay more one side then the other, there is no doubt to me that an unsized bullet would have shot more accurately.

Joe

[MTWeatherman]

The trick is to use two coats of LLA. For me, it works fine to 1850 fps in 357 mag and 30-30 using ww alloy.

Junior:
I've experimented with two and even three coats of Liquid Alox in two rifles on non-tumble lube type bullets. One was a .32 Special firing the RBS bullet at over 2100 fps. The other was a .44 Mag Trapper Microgroove barrel with velocities between 1500 and 1800 fps. Leading wasn't a problem with the .32 but the GC likely scraped any evidence of it away. Accuracy just wasn't there...instead of 1.5 to 2" groups, they opened up to 6" or more. Two coats eliminated the leading on plain base for for the .44, but with both GC and plain base bullets, accuracy went south with liquid alox compared to Javelina as velocity was increased. On handguns, I've had no problem and have used tumble lube in both and .357 and .40 S&W but velocities were below 1400fps.

My theory was that unless the bullet is tumble lube design, even double or triple lubing the bullets won't carry enough lube for higher velocity in the longer rifle barrels. Lee says that their lube is better because it coats the part of the bullet in contact with the barrel. Problem is that once the bullet is seated, it is scraped off and deposited either in the lube groove or on the top edge of the cartridge case...and I don't think enough is there to do the job.

I know that others have had better success than I and I don't doubt your experience a bit.

It could be that my experience is related to shallow groove barrels...both the .32 Special and Microgroove qualify in that regard. Higher lands and the problem may not so readily appear. Shallow grooves are not tolerant of any leading at all.

[KCSO]

I have also sized some bullets down pretty radically and don't find that it hurts the accuracy. I usualy use my lube/sizers to lube and then size in a seperate operation in a push through die. Done that way I have sized 8 MM to 30 cal and 338 to 8mm Styer and shot groups of under 3" with the factory irons. I cast all my 220's at 315+ and then size to 315, 314, 312, 311 and 309 depending on the rifle I shoot them in. The bullet sized to 309 in my 1903 Springfield with peep sights will consistantly shoot into 1 1/2" at 100 yards with this bullet and with the Lee 155 sks bullet similary sized. For years I heard that you shouldn't size over 2 thou. and when I finally got around to trying it I was amazed at the good results. I would guess that this may be another statement put forth by the ad men.

[JohnH]

Oversize bores and undersize boolits. Grrrrrr. First chance I had this year I bought the largest sizing dies I could get for caliber. I'm running 360 sizer for 358 caliber rifle if that gives you an idea. I use the lubrasizer to lube. Like others, it is just so convienient and mess free. I used to pan lube a lot,and even though it is cleaner to me than Lee's Mule Snot (:) I liked that one) it is still messy in it's own way, but my best shoting has come with bullets that at least match bore size. In these days when a maker tells you that they accept barrels that are =/-.002" of nominal, and chamber casts reveal no discernable throat, one is well advised to use as big a bullet as possible

[Buckshot]

............I suppose that sizing is like putting shoes on horses. A necessary evil on occasion. If you have an 8x57 with a .324" throat and the slug drops at .3255" whatta ya gonna do? I respectfully submit that if you care to shoot that design with that alloy, you'll size it so you can get it in the gosh darn chamber.

An alternative would be to have all custom moulds (cut by makers who understand alloy shrinkage) for each rifle and alloy you'd probably use. Okay Bill Gates, off you go.

The rest of us mortals have to live on what's out there, mouldwise. Hopefully most of the moulds one will aquire over time will drop, if not perfect, then exceedingly shootable boolits as is. The lube-sizing process then has the emphasis heavily on the lubing part.

I'm sure a lot of us already do that anyway. For the mentioned 8mm I'll bet most commercial moulds drop .325" on the big side, if that large. Sizing down .001" if needed is only .0005" around the circumfrence and that ain't much atall.

The problem with sizing is the potential to ruin the accuracy cast into the slug. Personally I've bent quite a few 311284's while sizing'em. It has that old scraper groove ahead of the front drive band. I've also cast with moulds that had offset blocks. Makes a oval boolit! You size them round but you'll see the bands are wider right up to the parting line, then they get skinnier on the other side. Since it's symetrical they're useable for short range stuff, but ideally you can get the block issue rectified.

..............Buckshot

[andrew375]

It is largely a historical thing, up until ww11 the dimensional and quality control of bullet moulds ranged from variable to abysmal. Particularly noteworthy were those that were part of the Lyman 310 "Tongue" tool. I think that in order to avoid making moulds that cast to small and to compensate for ovality they deliberately made the moulds too big so they could be reduced to the correct size and roundness by brute force; it being virtually impossible to achieve this from the opposite direction. Thankfully this largely appears to be thing of the past, due to better materials, skills and machining and measuring technology.

I now don't size any bullets at all. Even those that go though a lubresizer go though a die I made that barely touches the surface as the die only functions to crimp the gas check and apply the lube.

[StarMetal]

No matter if you size or if you don't...YOU ARE SIZING THE BULLET WHEN YOU FIRE IT!!!! What difference does it make if you size it before hand or not? Like alot of us I have sized bullets that shoot fantastically accurate. This is just another one of those idiosyncrosies that casters have in my opinion.

Joe

[felix]

Only size a boolit to make it fit the neck of a rifle/pistol, or the throat of each revolter's cyclinder exits. No need to size otherwise unless locking on a gas check that was meant to be locked on. ... felix

[Cloudpeak]

Only size a boolit to make it fit the neck of a rifle/pistol, or the throat of each revolter's cyclinder exits. No need to size otherwise unless locking on a gas check that was meant to be locked on. ... felix

Using straight wheel weights in my Lee 6 cavity, 40S&W tumble lube mold I will get a difference in diameter of several thousandths (sorry, can't remember exactly the difference. Maybe .003-.004. Just don't remember for sure). I size all my bullets through the Lee "push through" die. The last batch I sized and then lubed which might have been a mistake as some of the bullets pushed through with great difficulty. I was worried about increased pressure in my XD40 SC when firing a larger diameter bullet.

Cloudpeak

[Bret4207]

Cloudpeak- If you're getting diameters varying in several thousandths I'd wonder about the mould. I have a bunch of 6 cav Lee's and they all cast within .001 of each other. Other possibilites include crap on the block faces holding the blocks apart, an unintentional "Beagling" or maybe a warped mould. .003-.004 is a BIG variance and I'd want to know why I was getting it.

[NVcurmudgeon]

Cloudpeak, What Tpr. Bret said would be the first things I would check, too. another possibility is that you could be getting tired after hours of casting and not holding the mould closed with the same grip each cast. (I have cought myself dooing that even after many years of casting.) Finally, (you will need a lead thermometer for this) you might want to check to see if your heat source is consistent.

[carpetman]

NVCurmudgeon---Might be getting tired--not holding mold tight enough--have caught yourself doing that after many years of casting. What stamina,two weeks is about all I can hang in there for. No wonder you can shovel all that snow.

[Scrounger]

NVCurmudgeon---Might be getting tired--not holding mold tight enough--have caught yourself doing that after many years of casting. What stamina,two weeks is about all I can hang in there for. No wonder you can shovel all that snow.

CarpetMan can shovel a lot of, ur, ah, stuff, too.

[Cloudpeak]

"Cloudpeak, What Tpr. Bret said would be the first things I would check, too. another possibility is that you could be getting tired after hours of casting and not holding the mould closed with the same grip each cast."

NVcurmudgeon,

Bingo. I don't think I had the mold all the way closed on occasion. Thanks for the heads up NVC and Tpr. Bret.

Cloudpeak

[NVcurmudgeon]

Ray, Right, though I do have to shovel snow one handed because my other hand is formed to the mould handles, making it impossible to grip the snow shovel.

[9.3X62AL]

.....as this thread continues.

[Char-Gar]

I share the same feelings as Felix. I only size bullet so they fit the cylinder, or chamber throats. I size my Marlin 30-30 bullets .311 only because both rifles won't take .312. I size my Winchester 70 (30-06) bullets .309 because they won't take .310 and so forth.

Since going to nose first sizing, I find I can size far more than I once thought without losing accuracy. It is not the amount that ruins the bullet, it is the manner it is sized.

Recently I did an experient with my Browning Traditional Hunter in 30-30. I had one Lyman 311291U mold that casts .299X.310 and another that cast .302X.316. I sized the body and nose of the second to give the same specs as the smaller one. I shot them both over the same powder charge (16.5/4795) and the groups ( 4 five shot groups with each bullet) at 100 yards were the same. All between 1 and 1.2 inches.

If RCBS is correct the groups of the bullets sized down .006 on the body and .003 on the nose should have been 7 inches. Pure crapola!