DAMAGED 22 RIMFIRE BULLETS
4.0 HOW TO MODIFY CAST BULLETS
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Bullet dimensions change with the alloy used, (more tin and or antimony make the bullets slightly larger) and during sizing in Lyman 450 style sizers. I've had 25:1 bullet noses expand .006" when sizing from .312" to .309".
The ease of chambering a bore riding bullet, or of breech seating a bullet, is affected a lot by the hardness of the bullets. Soft bullets may breech seat easily, while hard bullets don't want to breech seat at all.
The hardness, alloy and sizing operations are all connected, and can operate to substantially affect bullet "fit" in the gun.
Most of the time a readily-available mold can be found that casts bullets that work well in your gun In unusual situations, we may need to do something to get a bullet that fits a particular gun. Here are some options.
If the mold produces bullets that are too big or too small, or that have the "wrong" shape, then there are a number of ways to fix the problem.
Trade the mold
I've had good luck buying and selling molds on the Internet auction sites, searching for a mold that casts bullets with the "right" dimensions or shape. Needing a 429421 mold that cast bullets of .433" diameter or larger, I bought several on the auctions and cast bullets with each until I found a mold that met my needs; then sold the others.
Vary the alloy
Adding tin or antimony to the alloy makes the bullets bigger and harder. Reducing the amount of tin or antimony makes the bullets smaller and softer. The 3rd Lyman Cast Bullet Handbook, pg. 58, shows that a 30 caliber bullet cast of pure lead would measure .3095" in diameter and in linotype would measure .3108"- a difference of 1.3 thousandths of an inch. Then changing the alloy in and around the wheelweight area of composition would vary the diameter less. Changing alloy composition within the normal range of alloys makes very small changes in diameter.
Size bullets down in a lubricator sizer
To make bullets smaller we can size the bullet down in a Lyman or Saeco or RCBS lubricator/sizer with conventional dies, or use the taper sizing dies as supplied by Don Eagan in these lubricator/sizers. These dies taper the bullet from bore diameter to larger than groove diameter, and come in various sizes. I have used one of these dies in 22 caliber, and was able to custom size the bullet to adjust seating depth. This die worked very well for me, and increased accuracy of the .223 Remington rifle the bullets were used in.
To make bullets larger and/or change the shapes, we can "Beagle" the mold (put pieces of tape on the mating surfaces to make the bullets larger), lap the bullet mold, bump bullets in the lubricator sizer or bump the bullets in a swaging die and press. All of these are explained below.
HOW TO BEAGLE BULLET MOLDS
(This is from John Goins, aka "Beagle", who wrote the first description of this process that I ever read.)
I suppose that at least once in our lives, every caster is plagued but an undersize mould.
This fault as I call it occurs primarily with Lyman or Ideal moulds. Many times, I have searched carefully for a mould only to find it casts small bullets when I finally obtain it.
Many designs suffer from this problem but it seems that certain moulds or designs are worse than others. Among these are the 457191, the 357446, the 429360, the 41032, the 427098 and the 429434. Then there are the true old classics you obtain that were just an ³ah s??t!´ when cut. I have a 358429 that drops bullets at .358 X .355 and that was just a manufacturer¶s
problem.
All of these moulds set in my mould cabinet for years and occasionally I¶d learn something and then try them again to no avail. Still too small.
After retirement, I had time to mess some with these moulds and try to improve them.
First was lapping with valve grinding compound. A very messy and often unsuccessful project.
The second attempt was to drill and tap the open side of the pin alignment hole and put setscrews in so that the mould blocks could be held partially open. This works but the proper adjustment is hard to establish and maintain. About .003´ clearance can be obtained before flashing occurs.
The third attempt was to take a 5/32´ spring pin and cut 3/16´ lengths off one end and drive them into these openings to hold the mould open enough to cause enlargement of the bullet. This method also works but the correct adjustment is very difficult to obtain.
About this time, I acquired an H & G #73 double cavity mould off E-Bay. Since I had 2 cav H & G moulds, I didn¶t worry about handles. When it came, my handles were too thick to fit the block cuts. I finally found that a set of Lyman 4 cavity handles would hold the blocks so that I could try the mould. I fully expected a .358´ diameter bullet but instead obtained a .361´
bullet. Close examination of the gap between the mould halves showed that there was a minute gap between the blocks. Removing the blocks, there was no gap so the handles were held apart exactly the correct amount to produce a nice large bullet.
I communicated this information to Orygun Mark and he drilled and tapped a set of handles to incorporate a single .002´ shim between a set of SC blocks and it worked for him.
We¶re getting somewhere now.
I finally located a set of shim stock at ACE Hardware of .001, .002, .003 and .005´
thicknesses. I cut and prepared a piece of .002´ shim stock and prepared to shim a DC mould by securing it behind the mould handle screw. Won¶t work as the alignment pins get in the way.
Back to the drawing board.
I had a roll of .003´ aluminum tape with adhesive backing. I tried that on a SC mould but the adhesive closed the vent lines on a .22 mould I was attempting to enlarge. Finally, I placed a large square of this tape below the cavity and small strips on either side. Success.
Now, back to the DCs. The same method of a large patch below the cavities and a small strip along the outside of each cavity works well and stays in place because of the adhesive.
Now, the 427098 which previously ran .428´ runs between .432 and .433.
I learned several things during this experiment.
1) Don¶t completely block the vent lines or incomplete bullets will result.
2) The shim must be directly between the mould handles. If below or above, the blocks will tilt and close. The shim must be directly between the alignment pins for the same reason.
3) For some reason unclear to me, bullets don¶t enlarge excessively sideways even though there is a gap there.
4) Even if bullets are slightly elliptical, sizing rounds them if done with a new style tapered entrance sizer and accuracy is just as good as with round bullets.
5) Very little flashing between the mould halves occurs using this method. If being dipper poured, they will flash. If using the bottom pour and dropping the melt 3/4"
to 1´ into the sprue hole, no flashing occurs due to reduced melt temperature and the reduction in the pressure of the melt going into the cavity.
Update«..
After several months of experimenting with enhancing moulds, I have learned a little more about it.
More uniform results can be obtained by applying tape to both halves of the mould.
Venting is not a problem as I first anticipated. Sufficient venting is provided by the gaps between the tape strips.
The best method of taping can be obtained by using strips approximately 1/8´ wide. If you want a bigger body, apply strips alongside the cavity and between the cavities in the case of a double cavity mould alongside the area you wish to enlarge. These strips should be positioned so that the two strips bear on each other. This separates the mould halves a uniform amount.
This method can also be used on the larger 45 moulds designed for black powder to enlarge the nose to full diameter for use in smokeless rifles and give a better bore fit.
Under the current method of taping, I am obtaining about .003´ in diameter without undue design distortion. This has been very useful in the .38, .44, 375 for the 38/55 and in the BP 45 designs in the 45/70.
Latest update. For some reason, if using only one thickness of tape in the mould, it seems to work best if placed on the side of the mould with the index pins. Haven¶t quite figured this one out but that¶s the way it works.
If there's any questions, contact beagle at goinsj3atgtedotnet beagle
From Joe Brennan
I've had good luck with "beagling" molds from .22 to .44 caliber, using just one layer of tape and making the bullets about .0015" larger in diameter. Two layers of tape gives me fins on the bullets that I can't get rid of. Others report using two layers of tape successfully.
After putting the tape on the mold it takes about 50 bullets cast to get the tape squoze down and the adhesive squoze out. These bullets aren't any good, they have fins.
The trick to casting bullets without fins in a beagled mold is to use as little heat as possible and/or to vary the tin or antimony percentage. The more tin or antimony, the more fins-for a given amount of heat. The heat can be reduced by reducing the temperature of the lead pot, by reducing the time the sprue plate is in contact with the ladle or nozzle, by allowing the mold to cool between pours, or by cooling the mold on a wet sponge between pours. I am able to get good finless bullets with beagled molds by reducing the temperature of the pot and minimizing the time the ladle is in contact with the sprue plate.
Here is the tape that I use. I got it from an air
conditioning mechanic; it is aluminum with adhesive and a paper backing. One foot should last a lifetime.
The 22-caliber NEI mold has tape on the bottom, to make the nose bigger.
The 311299 mold has 2 pieces of tape, one on either size of the cavity. This makes all diameters bigger.
HOW TO LAP BULLET MOLDS LAPPING BULLET MOULDS Ric Bowman
There are several reasons to lap bullet moulds: new moulds with machining errors and burrs, corrosion and stains, equalizing volumes of multi-cavity moulds and casting problems.
Other than for casting problems, most lapping has been done for cosmetic appearance and for match bullets, made as round as possible. I think everyone loves to make beautiful shiny bullets with zero runout, but it doesn¶t make them shoot much better for most of us.
I have never been able to make moulds cast bullets larger than 0.002 inches greater than originally cut, and still keep them round, by lapping. If you need a bigger bullet, buy a mould that casts a bigger bullet as manufactured. However, lapping can make bullets drop from the cavity easier and remove baked on material from the surface of the cavity.
Lapping is not a ³spur of the moment´ decision, but takes some planning and
forethought. The first thing you will need is ten of your best quality bullets cast and separated for each cavity you are working with. Wheel weight alloy is just fine except for polishing, and then
linotype alloy is probably best, as bullets are larger, harder and more closely conform to the cavity. The three most useful lapping compounds are ³Clover´
brand automotive valve lapping paste in ³fine´ grit, Brownell¶s 800-grit water based lapping paste and
³JB´ bore paste or ³Flitz´ polishing cream. (See picture)
To drive the lap, I use a small sheet metal screw that has a quarter inch head with a socket and
³T´ handle wrench. A small electric screw or nut driver may be used if you are careful and check your work often.
Let¶s talk about mass produced aluminum moulds first. One problem is that they are cut with the mould halves compressed tightly together. No one can hold the handles together as tightly as the fixture that was used in manufacture. This is the primary cause of out-of-round bullets with these moulds. In addition, the manufacturing process doesn¶t always have the
sharpest tooling and best chip removal process and that leads to burrs. These burrs hold the bullet into the cavity. The other problem is that unless you are using a perfectly clean pot, ladle and alloy, every bit of dirt, slag and carbon seems to stick to the surface of the mould cavity. It not only makes ugly bullets, they are not in balance, and bullets stick to the mould making you hit
the handle joint trying to get them to drop. While powdered graphite or mould preparation compound can coat the cavity, it doesn¶t last all that long, besides occupying space that should be part of the bullet.
All aluminum moulds are soft and easily cut with lapping compounds. That is both their strength and their weakness. Very easy to get results but very easy to mess up and ruin also.
When I get a new or a ³new to me´ aluminum mould, I clean it with hot water and automatic dishwater soap and a toothbrush. I scrub until clean and then hold it under the hot water tap, scrub until all the soap is gone, and about two minutes more. I dry it with a hair dryer I bought at a yard sale. Then prepare it for casting using what ever process the manufacturer suggest. When it starts casting well filled bullets separate ten good ones. Out comes the micrometer for
measurements. Are they round? Now put them on an accurate scale, are they a consistent weight? Did they release from the cavity easily? Out comes the five-power loupe to look for flaws, burrs and problems. If the decision is made to lap here is how I proceed.
Remove the sprue cutting plate if possible, if not, you will have to work carefully not to let it get in the way and to make sure nothing get under it to mar the top of the mould. A bullet is placed in the cavity and a 1/16-inch drill bit is used to make a pilot hole as close to the center and as close to vertical as possible. I used to do this in a collet with a drill press, but found that doing it carefully by hand worked just as well. Do not let the bit come close to the bottom of the grooves or touch the mould in any way. It just needs to be deep enough to be the pilot for the screw. The screw needs to have a small shank and only needs about three threads deep to hold it tight. Place the bullet into its cavity and tightly close the mould. Start to screw the screw in the bullet with the socket. As it goes in it will expand the bullet. Now you will have to adjust the size of the pilot hole or shank size of the screw so that you do not deform the bullet. Increase the size of the hole until you can get the screw firmly into the bullet without expanding it too much. This is a
³feel´ process. You are not trying to hold the earth together, just enough to keep it straight in the bullet and rotate the lap.
Coat the lube grooves, driving bands and bore riding part of the nose with lapping compound. A volume of about half the size of a pea in plenty. Try to avoid the end of the nose.
Place the bottom of the mould blocks on a flat surface such as a Formica workbench top, steel plate or square of plate glass. This will help align the mould blocks as the pins or guides will not be in full contact as they are closed. Insert the bullet into the cavity and hold it firmly together with the handles.
Now the ³art´ and not the ³science´ part of the project begins. The objective is to evenly squeeze the halves together, maintaining alignment, just tightly enough for the lapping
compound to cut without jamming the bullet. I have used both a helper with an extra set of hands and small rubber bands evenly applied around the mould blocks. When turning the screw do not apply any more downward force than necessary, just enough to hold the socket on the screw.
You are not trying to push the bullet down, just make it rotate. If you squeeze the handles too tightly, the bullet will seize in the cavity. You want it to have good contact to cut evenly, but not to keep turning the screw into the bullet. Ideally about 25 complete revolutions of the ³T´
handled socket driver will allow you to close the mould with about the grip of a firm hand shake, or the amount of pressure you use to hold the mould close when casting. If you are using the 800-grit compound, the coarsest I ever use on aluminum, you have increased the smallest diameter of the cavity about 0.001 inch.
Clean and dry everything just as at the beginning. Closely look at the cavity, as your goal is to have between a third and a half of the circumference of the cavity showing the different surface texture of having been worked. If it has not been touched, repeat the lapping process with another new bullet lap until you have about two thirds of the surfaced worked. When you reach that point, clean again and cast bullets until you start getting good ones and measure them to your specifications. If they are round enough for you and fall reasonably easy from the aluminum mould, it is time to polish. If not to your satisfaction, use another newly made lap. If you are trying to make the cavity larger in diameter, you must be careful. As the cavity gets bigger, you cannot keep the lap perfectly aligned with the mould and bullets will begin sticking or loosing concentricity. If they meet your dimensional needs, it is time to polish.
Polishing is to remove burrs and improve the surface finish of the cavity. Make a new lap and coat it with your polishing compound. JB is commonly used because most shooters already have it for bore maintenance, but others prefer Flitz because it is faster acting. The process is the same as using coarser grit but it takes about 100 revolutions to get an acceptable finish. This is where a small battery powered screwdriver comes in handy because you can check your work after five seconds of rotation. You do not have to make a new lap for polishing, but you must
Polishing is to remove burrs and improve the surface finish of the cavity. Make a new lap and coat it with your polishing compound. JB is commonly used because most shooters already have it for bore maintenance, but others prefer Flitz because it is faster acting. The process is the same as using coarser grit but it takes about 100 revolutions to get an acceptable finish. This is where a small battery powered screwdriver comes in handy because you can check your work after five seconds of rotation. You do not have to make a new lap for polishing, but you must