Information on Sizing and Lubing

This section is to explain several very important facts about differences in functions, operation and quality of the lubricator sizers that are available. Also important factors about which of our lubes to use. I am writing it because it has been a large part of the technical phone conversations which have tied up so much of my time. Please study it carefully and you’ll probably gain helpful knowledge.

If you are going to purchase a sizer we recommend a Star (available from Magma engineering, Queen Creek, AZ) if you'll be sizing only gas checked flat nose bullets.  They are the Rolls Royce of sizers, with tremendous lube injection pressure, to the point that it can cause leak problems if not understood, and production speed is about double what the other sizers put out.

Bullets are pushed straight through, with each new bullet pushing the preceding one out, which makes for problems with pointy spitzers.

To take advantage of the Star's potential with gas checked bullets, the pusher punch must be fairly close to sizer diameter, having about .010 to .015 undersize. Then its end needs to be cupped out a few thousandths so only about a 1/32 inch wide contact ring is left around the perimeter. This so all pressure is applied around the outer edge of the GC base, straddling any raised sprue etc. A punch of this description pushes GC’s on if they are a bit tight, then sizes them on with perfect concentricity to the bullet body, and perfect squareness around the critical perimeter of the heel.

By contrast, the other sizers crimp the GC on before any of the bullet enters the die, so if the check shank has any deformities, or if the check shaves lead a bit on one side when pressed on, the check, being far stronger than lead, will force the bullet to size out of balance at the base end.

That’s not a problem with LBT molds because we guarantee a slip on gas check fit, which prevents checks from shaving and going off center at all, and unlike cherried molds, our check shanks are perfectly concentric to the bullet.

At any rate, this tiny, and probably invisible bit of press formed precision can shrink groups from 2-3 inches down to tack holes! DO NOT OVER LOOK IT!

It does not work with plain base bullets in the Star, so if you want to process un-gaschecked bullets in a Star sizer, choosing a bevel base and pushing them through nose first works quite well, because the bevel edge isn’t affected by shrink like the flat bottom is, as is described below. I'll explain how to get the same results in the other sizers in a minute, after discussing which LBT lube to use in Star Sizer.

Star Sizers can use hollow sticks, but are designed for solid, and you get a bit more lube for your money while avoiding trapped air problems. If you happen to have hollow LBT lubes and some other brands which are not harmed by melting, you can melt and pour into the sizer, with any sizer in fact. Don’t wait for the lube to harden, just go right to sizing. You'll have to apply lube pressure a bit more often while it is solidifying, but otherwise you won’t know it’s melted.

LBT Blue will run great at room temperatures without a heater. Commercial is nicest if you have a heater. Blue soft works great at temps down to 40 deg F, but in warm work areas, apply less lube pressure to avoid leakage between bullets which will leave a streak of lube on the nose. You won't have trouble with blue soft at temps up to at least 120 deg if attention is paid to how tight the lube screw is tightened.

When using a Star Sizer, order your mold to allow .001 inch for sizing to prevent this leakage problem.

One other slight problem with Star sizers is that the bullets are sized dry, with lube injected after sizing, which makes sizing extremely difficult with large bullets having a hardness of 20+ bhn.

The solution is to spread your unsized bullets out and fog lightly with whatever dry spray lube you have on hand. WD40 works fine, but keep the application just a very light quick fog, and only the tops need to be hit. No need to roll over and get the other side, as the object is to apply a thin film of lubricant to the leading edge of the sizer die. One can also run a sized and lubricated bullet back through a second time as needed, maybe one out of five, if the bullets are real hard. There will be no problem with softer alloys, say 16 bhn and below.

If you elect to purchase one of the in-and-out sizers, avoid the Lyman, because they are extremely weak. If you happen to have one already, and don’t have a heater, use only LBT Blue Soft, or with a heater, Blue or Commercial will work fine.

RCBS makes a stronger one and offers a lifetime guarantee. They do break, but not often and the fix is free. Both operate the same way.

The RCBS will run Blue at room temperature, and really works smooth with Blue Soft, even at temperatures down to near freezing. If you want to use the hardest Commercial formula you’ll need a heater.

Some people warm the sizer with a hair blow dryer so they can use hard lubes, but I don’t recommend going to that hassle with LBT lubes. Choose LBT Soft and you'll probably never look back. If you use a blow dryer to heat the sizer, lay the bullets out one layer deep and warm them till nice and warm to the touch. When warm lube touches a cold bullet it instantly hardens, but like a hot knife in butter, a warm bullet will make the lube slip into the grooves with ease, and heat the sizer die better than blowing heat on the outside. If working in a really cold shop, you'll love handling the warm bullets!

Our softest, the Blue Soft, is nearly impossible to tell from Commercial once it's on the bullets, and never comes out on your fingers. It’s what I use exclusively in the RCBS and never turn the heater on, though it’s equipped with one.

Now about sizing with these sizers. We offer fitted punches for all our bullets and recommend that you purchase one for every caliber and nose shape. For example a 44 LFN punch fits all 44 LFN bullet weights. Use a flat punch that’s close to bullet diameter if you want to size noses only on these sizers. And when sizing noses only, back off all lube pressure.

To square bullet bases on both gas check and plainbase using these sizers, have the lift-out plug machined as described for the Star pusher punch above.

When you size, press down at the bottom of the stroke until the liftout plug prints a ring around most of the perimeter of the bullets base.

There are no molds made which cast squarer based bullets than LBT molds produce, but even though the moulds are precision made, bases shrink a little out of square because that’s the last part of the bullet to solidify, and this is the only sensible fix.

Understand that nose pour bullets have very square bases but it is impossible to cast nose pour without internal shrink voids, which throw accuracy off on occasional bullets worse than slightly out of square bases from a base pour.

By design, not accident, LBT molds do not allow hidden internal shrink voids when used as directed. A claim no other mold maker can make.

At any rate, LBT molds solve the internal void problem the only way it can be solved and the little out of square base problem is fixed with certainty as described above. Do this bump squaring of bases with bullets from all molds, because they all have the same problem, but far worse than LBT.

I’ve explained about sizing the noses of oversize bullets down to groove diameter. Understand that our straight rifle bullets, when sized full length, will conform exactly to the rifles throat and chamber when hit with heavy loads. Carefully fitted (tapered or step-sized) which many target shooters make, will do the same.

In either case accuracy will not be as tight as with lighter loads which do not deform the bullet upon firing. In other words, for tightest target accuracy, some velocity under 2000 fps, that can be obtained at chamber pressures which do not crush the bullet, will be required with most guns, while specially built cast guns can do it at higher speeds.

Please read Jacketed Performance with Cast Bullets, which goes into far more technical detail on these and all other matters that pertain to casting.

Lead Bullet Technology

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