Bullet Sizing And Lubrication

Bullets and their sizing and lubrication arc subjects so closely related to one another that it is impossible to consider them separately. Consequendy, diere is some overlapping of these subjects that can not be avoided, especially when lead alloy bullets are involved.

Jacketed bullets, as made in the United States, require no lubrication nor do they have to be sized in any way as they arc made corrccdy for the cartridges they are intended to be used in. The .303 British service bullet which uses a cupro-nickcl jacket, has a shallow groove filled with lubricant, the groove being covered by the case neck.

Some seventeen or eighteen years ago when our own military rifle shooting was all done with the old Model 1906 cartridge, loaded with a cupro-nickel bullet, riflemen used to lubricate the bullets externally. The cupro-nickel jackets, at velocities of over 2,000 f.s., left a thin deposit of metal fouling along the muzzle end of the bore for about 6 inches. This fouling would build up in lumps and streaks, impairing the accuracy of the arm until it was cleaned out and the cleaning was a troublesome process. Someone got the idea that lubricant on the bullets would prevent this metal fouling. A rifle was taken out on the range and fired a limited number of rounds with bullets that were dipped in and thinly coated with Mo-215 bilubricant, a heavy automobile grease. The rifle did not metal-foul as might normally have been expected and without more ado Mobilubricant was hailed as a panacea for metal fouling.

For several years one couldn't find a rifleman on the line without his little tin box of Mobilubricant in front of him. For slow fire the bullets were dipped one at a time and for rapid fire the bullets of all the cartridges in the dip were greased before they went into the magazine or the belt. But during this period, the Ordnance Department began to get an increasing number of rifles with cracked bolt lugs or worse. Investigation finally disclosed that the Mobilubricant was causing the trouble. The greased bullets, rubbing against the hot chamber left grease in the chamber, or resting in the hot barrel for several seconds before firing, the grease melted and the excess leaked back into the chamber.

A cartridge case under normal conditions grips the walls of the chamber when the cartridge is fired but with lubricant in the chamber there was no grip and the case was driven violendy back against the bolt face with more force than a rifle bolt is made to stand. As some shooters put great gobs of grease on their bullets, it is probable that in some instances the grease filled practically all the normal dearance between the cartridge, reducing the expansion of the cases and causing higher pressures than usual. In any event, a thorough investigation was made of the virtues of external lubricant on jacketed bullets and it was found that it really had litde or no affect on metal fouling. Proper publicity was given this, as well as to the dan-

gets of lubricant in chambers, and the practice disappeared as prompdy as it sprung up.

The method of measuring chamber pressures in small arms in Great Britain utilizes the set-back of lubricated cartridge cases, the copper crushers occupying a place between the head of the cartridge case and the face of the bolt of the special guns made for this purpose.

However, die practice of lubricating jacketed bullets is pass^ and is entirely unnecessary with gilding metal bullets anyway. Cast bullets when loaded in old black powder arms, with one or more lubrication grooves exposed, should be loaded into the chamber carefully to avoid greasing the chamber walls. The margin of safety of some of the older arms is not too wide, even with black powder loads.

Lead or lead alloy bullets cannot be fired with accuracy unless they are lubricated. If unlubricated, or if the lubricant is not of the proper nature, lead will rub off on the inside of the barrel and destroy its accuracy until cleaned out. For this reason, cast bullets are provided with grooves to carry lubricant, and these grooves must be filled in one way or another before the bullets are fit for use.

A bullet, as it comes from a mould, will probably contain some litde irregularities. Most moulds cast bullets a few thousandths of an inch over size to allow enough surplus metal so the bullets can be trued up pcrfccdy round and to the corrcct diameter by forcing them through a die of suitable size.

The best way to size and lubricate bullets is with either the Bond or Ideal bullet lubricating and sizing presses. They are both of the same general design, operate the same way, and do equally good work. Any reloader will do well to equip himself with one or the other of these litde machines, especially one who does a considerable amount of reloading.

But bullets can be sized and lubricated pcrfccdy by two separate operations. The bullets are first lubricated and then forced through a resizing die. All of the reloading tool manufacturers can furnish bullet sizing dies that are either used as attachments for their reloading tools or separately.

Many of the older Ideal Tools have bullet sizing holes through the handles, through which the bullets arc intended to be forced point first. Unfortunately, this usually 217 docs more harm than good to the bullets, as the excess metal is forced back and sometimes makes ragged bases on the bullets. Furthermore, the bullets arc apt to tip as they come out, which further deforms the bases, This type of construction has been discontinued but, if you have such a tool, good results can be obtained by forcing the bullets through the hole base first. This will probably result in some slight deformation of the bullet point from the pressure of the plunger, but this is by far the lesser of the two evils. A better remedy is to get a bullet sizing chamber for die tool if it is of the adjustable type, or one of the several bullet sizing tools on the market.

There are two simple, if somewhat messy, ways of lubricating bullets. The first and oldest method is to stand the unsized bullets on their bases in a shallow box or dish and pour melted lubricant around them to a depth that will cover all the grooves. After the lubricant solidifies, the bullets may be cut out with a "kake kutter," which is a name given to a cartridge case with the head cut off or bored out and the mouth sized slightly larger than the bullet diameter. Any tubular article of suitable size, through which the bullets can pass freely, will do. The bullets arc picked up by the kake kutter as it is pressed down over the bullets one after the other, the preceding bullets being forced up and out the top. As each bullet is forced out, take it with the fingers and set it down carefully, so the base will not be damaged.

This will leave your bullets in a condition that can be best described as a gooey mess, but they should not be wiped off. The next step is to force them through your bullet sizing die. This will size them and help to forcc the grease into the grooves. It will also scrape off much of the excess lubricant. In handling the bullets, try to avoid picking them up where the lubricating grooves are located. The lubricant is liable to adhere to your sticky fingers better than it does to the smooth surface of the lubricating 218 grooves. After the bullets are sized the surplus lubricant can be wiped from the bases and points of the bullets. They should then be packed ncady in small cardboard boxes so they cannot tumble about and damage their square bases.

Bullets can also be lubricated by holding them with the fingers and dipping them, one at a time, into melted lubricant, then standing them on their bases on a sheet of paper or tin. The lubricant will coagulate on the cool bullet and the excess is cut off with a kake kutter as dcscribcd above. This is the best method of the two; it is quicker and possibly a bit cleaner.

There are a few bullets that have bands of different diameters that arc not intended to be sized. The Belding & Mull, Squibb-Miller, and Ideal Pope bullets are notable examples of this type. These bullets must be lubricated by hand as just described.

Were it not for the leading which will result from the use of dry bullets, the problem of reloading ammunition would be gready simplified; therefore, the subjects of bullet alloys and bullet lubricants are closely related, and a word about the distribution of the lubricant on the bullet will not be out of place here.

Inside Lubricated Bullet

The idea of lubrication is to have a film of lubricant between the surfaces where friction is likely to occur. Many bullets are poorly designed with respect to the location of the lubrication groove or grooves, and many of them, especially revolver and pistol bullets, have only one wide groove. The drawing on this page is typical of such bullets, and shows how more than 50% of the bearing surface of the bullet must come into contact with the 219 barrel before any lubricant in the groove becomes effective. The lubrication of the forward part of a bullet of this kind is dependent upon the lubricant left in the barrel from the preceding shot, and the amount and virtue of this residual lubricant will depend upon the composition and consistency of the lubricant used, as well as the bullet alloy.

Use of Grease or Wax Wads.

The practice of using a wad of wax, or wax softened slighdy with grease, under the bases of bullets, either with or without a card wad between them and the powder, is as old as breech loading arms. The practice has had a recent revival and it is claimed that the use of colloidal graphite in the wads has some particular virtue in preventing leading in revolvers and reducing erosion in some rifles. Perhaps it has, but the practice of using fusible wads of any kind behind bullets should be approached with caution.

As has been explained elsewhere in this book, there is every indication that the neck of a cartridge case expands before the bullet moves forward to seal the bore and that a certain amount of gas escapes between the case neck and the bullet. This is a normal condition and the escapage of gas influences the chamber pressure. If the case neck and the chamber are such a dose fit that there is no expansion of the neck and no escapage of gas past the bullet, the pressure developed by the charge will be materially higher than normal. This is the condition found in spccial tight chambers.

When a wax wad is used under a bullet, the density of loading is increased, if the bullet be seated to its normal or prescribed depth, which, if not influenced in any other way, will cause some rise in pressure. If the clearance between the expanded case neck and the bullet be small, the melted wax will seal the space, just as oil in an engine cylinder seals the gas from passing the piston. This will cause a considerable increase in the chamber pressure and 220 create a condition analogous with that of the tight chamber. Therefore, if a fusible wad is used under a bullet, I would suggest in the interest of safety that the thickness of the wad be considered as part of the seating depth of the bullet and that any full charge of powder be reduced at least two grains in weight, just as when loading cartridges for tight chambers. This applies especially to the newer cartridges such as the .257 Roberts and the .220 Swift, as these calibers have a closer relation between case necks and chambers than some of the older calibers. I also believe that any reduction in erosion obtained from the use of grease wads is due to their effect in preventing the gasses from rushing past the bullet plus possibly some lubricating cffcct between the unburned powder grains and the barrel.

Where there is several thousandths of an inch between the expanded neck of the case and the bullet during the cycle of combustion» or when the clearancc is great enough to permit the melted wax or grease to be blown past the bullet, the increase in pressure will not be so great but unless the clearance be considerable, there will be more or less increase. We can compare the effect of a grease base wad in a tight chamber with a normal automobile cylinder in which the oil seals the gas above the piston and the normal chamber with an automobile that pumps oil. The difference in both cases is purely that of the amount of clearance between the moving metal surfaces.

The cffcct that these grease base wads have on pressures can only be determined with a pressure gauge but the effect on lubrication can easily be seen by anyone interested enough to make a simple experiment.

Any normal military rifle is all right for making the test which is as follows: Cast up some bullets of any alloy but do not lubricate them. Load ten of them, dry, with a moderate charge of powder and fire them. Ten will be enough to give the barrel a nice dose of. lead, x Push a dry patch through the bore to remove the surface powder fouling and any loose bits of lead and observe the condition ot the bore so you will have a good mental picture of it for later comparison. Then, scrub as much lead out as possible with a dry brass brisde brush, plug the chamber tighdy with a cork or wooden plug and load the barrel with metallic mercury to remove the remaining lead. There will probably be from six to ten inches of it and it must be completely removed. Incidentally, if the arm is ordinarily used with lead bullets it should be doped with mercury before you start the test. Thoroughness and uniform conditions are necessary if the results are to be of any value at all.

When all the lead in the barrel is amalgamated and the bore wipes out clean, repeat the process exactly as before except that the bullets must be seated on top of wads of wax or grease. Anything that you use for bullet lubricant will do and the wads do not have to be of any exact thickness. I suggest a thickness of from 1/32 to 1/16 inch. The results you get this time will depend upon the amount of powder used and may vary from no leading ar all rn a fair amount for a short distance, starting a couple of inches ahead of the chamber. The heavier the charge, the farther the leading will extend along the barrel and the more it will build up but with a light or moderate powder charge it will not amount to much and most, if not all of it, will come out with a littie wire brushing. Always wipe the bore with a dry patch before examining it, as otherwise you may mistake powder fouling or other corruption for leading. The point is that some of the grease from base wads docs blow past the bullet under the circumstances mentioned and lubricates the bore ahead of the bullet.

A few points to observe are: to wash all oil from the bore before firing each test; wipe the bore with a dry patch before examining it; use bullets from the same lot, and if the charge is a light one, use cases that have been 222 expanded by previous firing without sizing the necks. The bullets can be held in good enough by crimping.

Because of the gas-check effect that the grease has in a tight chamber, their use can be considered as dangerou* with heavy loads.

In revolvers, the use of a grease wad under the bullet is nut au seiiuus as diere is usually pleiuy of expansion of eases in such arms. If over sized bullets are used the situation may be changed, as the whole idea depends upon the clearance between case and bullet and may be very different in two different calibers or even two arms of the same make and caliber.

Grease or wax wads should be of a fairly hard consistency and should remain solid at any ordinary temperatures under which they are likely to be used. Otherwise, they may melt and run down into the powder charge, preventing all or part of it from burning properly. There is some indication that the powder which comes in contact with grease wads does not burn but that is getting into someone else's thunder, which is out of my line.

Making Grease Wads. These wads can be made from any bullet lubricant that is normally satisfactory for lubricating bullets in the usual manner. The only advantage that one substance will have over another will be in its intrinsic lubricating properties, as it will function in the same way whatever it is made of. If the wads are to be cut out and handled separately, they will have to be a litde harder than ordinary bullet lubricant. They can be made by dipping a bottle or glass plate into the melted lubricant and removing it quickly. The wax will coagulate on the cold surface, leaving a coating that can be stripped off before it sets up hard. If the mixture is too soft, you won't be able to get it off the glass in a sheet. After it hardens, the wads can be cut out with a wad-cutter made from a cartridge case with the head cut off and the mouth sharpened a litde by beveling it with a knife. Wads made in this way are usually very thin and for thicker ones, the melted lubricant can be poured onto a glass plate. Grease 223 wads arc most easily and nicely handled by leaving the lubricant on the glass. After the cases are charged, the mouths of the cases can be pressed up against the plate and slid off, each case cutting its own wad perfecdy. In seating the bullets, the bases should not go in far enough to push the wad back into the body of a botdc neck case for, if the wad fails to stick to the bullet base, it will be ineffective. Seating them that deep is inadvisable anyway.

Bullet Sizing.

Now, about sizing bullets; most of that has been gone over under the subject of "Bullets" but bullets are lubricated to prevent leading and the way they are sized has much to do with this". Many of the newer bullet moulds, especially those for rifle bullets, drop their bullets so large that they can not be sized down to a proper diameter without nearly obliterating the lubrication grooves. One of the things that you will observe, if you try that litde leading experiment just mentioned is, that at low velocities, there is very litde tendency for a bullet to lead a barrel once it is fully impressed into the rifling; it has reached a point where the base is no longer expanding and is only sliding along through the bore. And this with a dry bullet tool As the velocity is increased, there is an additional thrust against the driving edges of the lands and the leading is carried farther up the barrel. As the velocity increases the leading increases and the higher the velocity the more important proper lubrication becomes.

Let us suppose that we have one of these gosh awful

Cal. .30 bullets that casts about .516" to be sized to .311" which is 003" too large for most Cal. .30 barrels. Sized to .311" it carries a fair amount of lubricant as we look at it, but when fired the lands not only cause lead to be displaced back over the lubrication grooves but the whole surface of the bullet must be swaged back as well. We can't size the damned things down to .308" if the bullet has a gas-check as trying to

224 force a .311" gas-check through a .308" die will bust the lubricator. If we could, we would see the grooves considerably decreased in width and made more shallow. Narrow grooves would practically be wiped out. Whether the sizing is done in a die before the bullet is loaded or afterward in the barrel, the net result is the same.

If one of these bullets is driven at a high velocity, the lubrication that it carries may hold out till it gets to the end of a 24" barrel but be insufficient to take it out of a 30" barrel. Actual tests have shown such bullets to lead six inches of a long barrel enough to destroy the accuracy, but by reducing the velocity considerably they would get all the way through without leading. Which comes right back to the effect of velocity on leading.

Somewhere else I have referred to the edges of the bases and bands of bullets being blown off by gas rushing past the bullet before it moves up into the rifling. (See "Revolver Cartridges".) The same thing happens to rifle bullets in normal chambers and, it is reasonable to suppose, a certain amount of lubrication is blown out of the grooves at the same time. In a rifle, all of this lubrication is blown into the barrel but in a revolver it is not and more or less of it escapes between the barrel and cylinder. After firing the latter arm a dense, greasy residue is always found plastered around the rear end of the barrel. This means less lubricant on the surface of the bullet, where it is most needed. The heavier the powder charge, the more lubricant blown out of the grooves and just when the bullet needs it most because of the higher velocity. Revolver bullets should not be sized large enough to fit the throats of their chambers and consequendy, there is no way to check this loss. It gives no trouble with properly designed bullets at normal velocities.

Now let's see if we can briefly gather together in a concrete resume some of the scattered generalities about sizing bullets, here where they will be available for ready reference.

225 1« Cast bullets for rifles should be sized to not less than the groove diameter of the barrel they are to be fired in, and those for revolvers should be so-called standard diameters or the diameters of factory bullets of the same calibcr— unless there is some very definite reason for doing otherwise.

2. The ability to size bullets to their proper diameter is limited by the design of the bullet and its size as it comes from the mould. Many moulds cast bullets that are entirely too large. If these bullets are sized down to the normal groove diameter of the barrel of their caliber they may size off center and the lubrication grooves will be decreased in width and depth to a point that may easily cause leading.

3. The cxact method or tool used for sizing bullets is not important except; that they should never be sized point first. When sized base first, the die or tool should have a recess that will receive the bullet as cast and ccntcr it over the reducing part of the die. Top punchcs of lubricating and sizing tools or of sizing tools and chambers should fit the points of the bullets properly.

4- The apparent off-center sizing of bullets is more often due to a slight excentricity in the bullet as cast rather than to lack of alignment of the sizing die and punch.

5. There may be a tolerance of about .0005" from the diameter marked on a bullet sizing die. This tolerance is almost always on the plus side and is of no practical consequence.

Things to remember:—

That the size of a cast bullet has an effect on leading in addition to the amount and kind of lubricant used, the velocity at which the bullet is driven, the heat and pressure developed behind the bullet, the tolerance in the neck of the chamber and the amount of gas that escapes past the bullet before it moves into the rifling, the melting point of the bullet alloy and the hardness of the bullet.

The more the diameter of a bullet exceeds the groove 326 diameter of the barrel it is fired in, the more apt it is to lead the barrel. The reverse seems to be true with some bullets in revolvers but this is due to the lesser reduction of the lubricating surface of the larger bullet plus a smaller escape of gas past it due to its filling the throat of the chamber better. This sometimes has a beneficial effect in a short revolver but seldom in a rifle barrel. However, the causes of leading arc so many and so inter-dependant that no hard and fast rule can be laid down.

Bullets can not be arbitrarily sized smaller to reduce leading. Everything depends on the design of the bullet and whether its as-cast dimensions will permit the reduction in size.

Chapter Nine **7

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