Precision Ballistics LLC
precisionballisticsllc.com
Swaging Process Details:
 
Overview:  Bullets are manufactured in various ways. My custom bullets are hand-swaged. Bullet swaging is a method of using extremely high pressure (approaching 80,000 PSI) at room temperature to force a lead core into a copper jacket to form a bullet. Unlike casting, no heat or molten metal is used. The high pressure is applied with special, powerful presses, each designed to hold a precision, diamond-lapped, carbide die. I dedicate a separate press to each of the several dies needed to make bullets to assure that there are no variances due to switching dies on a press.

 

  • The first die squirts (forms) cores which makes the lead cores to the exact size and weight for all my various bullets.
  • The second die seats the lead core into the copper jacket. I use one die for flat base, another die for short boat tail bases, or another die for  low drag bases.
  • The third die points up the bullet with either a 6/9 dual radius ogive, an 8 ogive or a 15 ogive for low drag bullets, and forms the open tip meplat.  I use one die for the 6/9 ogive, another for the 8 ogive or another die for low drag bullets, and different punches for flat base, short boat tails, or long boat tails.
  • The fourth die is used only for all of my low drag bullets, to close the tip to a very high ballistic coefficient point with my custom Hoover tipping die. 

 

My bullets are 0.24300" diameter at the bearing surface and 0.24350" at the pressure ring, and are currently offered in 6mm, with a dual radius tangent 6 (with just a little secant 9 near the tip) ogive, or a single radius tangent 8 ogive, and have a 0.04000" open tip meplat, in either a flat base, or a 0.06200" by 14 degree, slightly rebated, boat tail base. My low drag bullets come in 90gr, 95gr, 100gr, 103gr, 105gr, 108gr, 113gr, 115gr, 117gr, 120gr and 125gr. My low drag bullets have a tangent 15 ogive, a closed point, (0.005" meplat), and a long 10 degree by 0.17500" boat tail, which is slightly rebated. They are built with precision jackets.
 
Flat bases have slightly more surface area for the combusted gases to push against and are generally considered most accurate at shorter ranges, such as 100-200 yards. Boat tail bases are more aerodynamic and have a slightly higher ballistic coefficient (BC) than flat bases. Bryan Litz wrote in his book, Applied Ballistics For Long Range Shooting, "In a word, the ballistic coefficient is a measure of how well a bullet penetrates the air. The attributes of a bullet that will determine how well it penetrates the air are: weight, cross-sectional area, and form factor." Boat tails have slightly less bearing surface and less dynamic core pressure which provides less friction and keeps the jackets a little cooler.  This increases their velocity from flat base bullets of the same weight and they are more stable for longer distance shooting, such as 300 plus yards because they have a lower drag coefficient and produce less air turbulence. Bryan Litz defines drag coefficient in his book, as "a dimensionless quantity that has to do with how much drag the bullet will have at a given speed. More streamlined shapes have lower drag coefficients and at supersonic speeds, the drag coefficient changes a lot with velocity." Bryan Litz states that boat tails are less precise than flat base bullets because by adding the boat tail there is potential for imperfections like making the boat tail off center. Also, boat tails are more susceptible to muzzle blast and may cause the bullet to pitch and yaw, and they require a higher twist rate to stabilize. In his book, he summarizes, "The reason why we use boat-tails is because at extended ranges, the aerodynamic benefits overcome atmospheric variations better than flat bases, and make up for the marginally compromised precision potential." As a bullet loses velocity, base drag becomes more prominent in overall drag, thus boat tails, which have less base drag, work better at longer distances since the velocity drops the further out you shoot. This function is not as significant when shooting under 300 yards, so flat base bullets are theoretically better for shorter ranges. Look for my low drag bullets in Bryan's new 2nd edition, now available! 
 
I find that my customers and I are experiencing extremely good accuracy and precision with both my flat base and boat tail bullets out to 600 yards, and my low drag bullets excel particularly well at all ranges from 100 yards to 1000 yards! I close their 0.05600" meplat to about 0.00500" with a third tipping die, custom made for my low drag bullets by John Hoover, to increase their ballistic coefficient. Because both my standard 0.06200" boat tails and my 0.17500" low drag bullet boat tails are slightly rebated, they combine the best features of both a flat base and a traditional boat tail base. Adding the rebate provides a more consistent and precise base like a flat base, making them inherently more accurate than a standard boat tail. Because they are also a boat tail, they offer the benefits of a boat tail and so a rebated boat tail is sort of a hybrid between the two designs. As the bullet leaves the muzzle, it is in a transitional state, no longer inside the bore, but still being propelled and effected by the escaping gases. This is where the yaw and the helical path is introduced, and a rebated boat tail allows a quick release of the gas and is directed more away from the bullet which has a smaller effect than a standard boat tail, theoretically making the rebated boat tail more accurate (published claims are up to 15% more accurate), and regarded as superior, to both flat or regular boat tail bullets. They reportedly gain up to 10% in muzzle velocity, while being easier on barrels.
 
The open tip design has long been revered for it's accuracy.  It is designed for precision shooting, rather than to expand upon impact like a hollow point design. A jacketed hollow point bullet has a fairly large hole specifically added to the tip, whereas an open tip bullet gets it's small open tip as a result of forming the jacket into a bullet in the point up die. An open tip design has an extremely small aperture compared with a hollow point design. The open tip lightens the forward section of the bullet, shifting the center of gravity towards the back of the bullet. This produces an improved ballistic coefficient, greater down-range velocity retention, and greater resistance to crosswind deflection.
 
The common abbreviation for "grain" is gr., but highly sensitive scales use gn. as the abbreviation for "grain" to avoid confusion with grams. I have chosen to use gr. rather than gn. because it is most used, but both abbreviations mean the same thing. I make both my flat base and boat tail precision custom 6mm benchrest bullets in eleven weights from 62 grains to 100gr, and offer them in three different ogive styles. I make all of my bullets, including my low drag bullet design bullets in 90gr, 95gr, 100gr, 103gr, 105gr, 108gr, 113gr, 115gr, 117gr, 120gr and 125gr with precision jackets. That's over 100 6mm bullet designs to choose from! Each one is made with precision copper jackets, long known as the very finest jackets available with the closest tolerances in the jacket walls, consistently within 0.0003". My lead cores are squirted, cleaned and degreased with the best solution available, so the product you receive is as precise as I can provide it.
 
My bullets prefer to be jammed into the lands around 0.010". My bullets all shoot sub 1/4 MOA. Because the bullet weight, bearing surface, ogive, case neck sizing, etc. likely differ from what you currently shoot, you must precisely measure your rifle's head space and experiment with your seating depth to find the exact total over-all length your rifle shoots best with, as well as experiment with the neck size of your brass to effect the internal pressure. Don't expect bugholes right out of the box until after you've done your experimenting with the variables. 
 
Offering you the options of having the frequently winning dual radius 6/9 (tangent 6 with secant 9 right at the tip), my new higher BC single radius tangent 8, or my highest BC tangent 15 ogive, and offering them with either flat, slightly rebated boat tail, or slightly rebated low drag long boat tail base, and putting a proprietary closed tip  (I can put any size between 0.005" and 0.060" meplat) on my  low drag bullets, sets Precision Ballistics LLC apart from ALL other custom bullet manufacturers! Give me a call at 702-331-1337 (I'm in PST). If you wish to visit my shop or mail a check I'm located at 360 E. Paradise Hills Dr. Henderson, NV 89002.
 

I believe in redundancy. I have at least two of everything needed to make my bullets to avoid down time when something breaks. My new Nevada shop is actually the front bedroom suite of my new house. I am able to keep temperature and humidity constant and comfortable, and have installed four 4' double bulb fluorescent light fixtures for very good lighting. My shop consists of 25' of stainless steel workbenches with eight new Redding presses mounted on them at 3' intervals. I mounted them at 20 degrees and put a magnetic box under each to catch seated or finished bullets. I dedicate specific dies to specific presses to reduce having to exchange dies very much. I keep supplies in the adjoining walk-in closet, and I lube jackets and ultrasonically clean and dry finished bullets in another room prior to packaging. Using my jeweler's scales, I weigh out exactly, to the hundredth of a grain, the same amount of my swage lube (2.5gr/1000) to apply to jackets in my two swage lube tumblers. Each jacket receives the same amount of lube (0.0025gr) to assure proper function in my carbide dies and proper finished length of each bullet.


Precision Jackets: The jackets I use have a Total Indicated Run out (TIR) less than 0.0003". They possess the uniform wall thickness vital to accuracy due to a state-of-the-art computerized manufacturing process. Concentricity and weight are controlled per lot. Precision Ballistics LLC  uses only the finest materials in our manufacturing process. All customer orders are made up from the same jacket lots. All of my bullets use brand new precision jackets, however some of my finished bullets may be slightly discolored when the jackets arrive to me discolored. While I have tried to polish them up physically and chemically, this discoloration remains and doesn't appear to hurt their performance.

 
Precision Cores, Swage Lube, Degreasing Process:  Each core is cut with a high heat-treated core cutter and swaged through a precision squirt die to be the exact weight needed for the bullets I am manufacturing. I run each bullet through the same set of renowned Detsch carbide precision swaging dies for consistency. I blend my own premium swage lube, of four parts 100% pure anhydrous lanolin and one part 100% pure neatsfoot oil. It is used to lube cut cores before squirting them, as well as the jackets before they are loaded, seated and pointed up. It is completely removed from the squirted cores before they go into the jackets, and from the finished bullets ultrasonically at 60kHz with Axarel 2200 ultra high purity dielectric solvent, which is heated to 160 degrees in my ultrasonic cleaner. It is a "green" environmentally friendly, non-corrosive, non-carcenogenic, ozone-safe and is approved for the aerospace, military and airline industry. This is the choice of the entire jet industry to clean their metal parts and printed circuit boards. It is the degreaser/defluxer used by NASA and throughout the electronics industry. It leaves no residue, as do many other degreasers used in the custom bullet industry, which allows a perfect bond between the lead core and the copper jacket during the seating process. It removes all of the swage lube and turns the dull finish of both the copper jackets and the lead cores into a shiny jeweled finish. Axarel is an extremely expensive degreaser, but it is worth it to make the best bullets for serious competitors.
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Precision Core Squirting, Core Seating and Pointing Up: Each bullet I make goes through the same set of renowned Detsch carbide precision swaging dies, custom crafted to my exacting specifications, mounted in nine Detsch-converted, Redding presses that swage each bullet under approximately 80,000 PSI pressure. Each die has it's own dedicated press so there are no minute changes from interchanging dies in just one press. There is a press for the squirt die to form the lead cores, a press for the flat base seating die, a press for the short 6/9 ogive point-up die for 62gr-70gr bullets, a press for the long 6/9 ogive point up die for 74gr-85gr bullets, a press for the 8 ogive point up die, a press for the short boat tail seating die, a press for the long boat tail seating die, a press for the low drag point up die, a press for the low drag tipping die. These presses are made to extremely tight tolerances, which removes all "lever-wiggle" as they are put through their cycles and allow for the proper amount of pressure required to swage bullets. They have been "trued" so each ram cycle is the same and is concentric with the centerline of the press. Using the same set of dies in dedicated presses for each bullet assures the great consistency that is required to manufacture precision benchrest bullets. I use a jeweler's scales that weighs to 0.01gr. when setting my squirt die to get the setting as close as I can make it. Each lead core is manufactured (cut and squirted) identically and is seated in identical jackets, (each customer order comes from the same lot of jackets and that lot number is on the bullet box label), under identical conditions, and each bullet is pointed up identically. Further, at your option, each meplat will be uniformed and counter sunk identically by hand (three turns each for both processes). I manufacture my bullets with either a flat base having a 0.24350" pressure ring, with a short boat tail base, with a 6/9 dual radius ogive. The short boat tail starts distally from the base 0.06200" and cuts back toward the base at 14 degrees, which provides outstanding flight stability. Then going up past the bearing surface, the first radius is a 6 tangent ogive, which is blended into a 9 secant ogive near the tip, that continues to the 0.04000" open tip meplat. My 90gr and 95gr BT and my low drag bullets have a 0.17500" by 10 degree boat tail and is used on my bullets built with the 1.050" and longer jackets. The pressure rings on my low drag bullets are 0.24350". My low drag bullets all have a tangent 15 ogive that has been closed to 0.00500" at the meplat. The word ogive is from the French for a curve, and is pronounced "OH-jive".

Cutting and Squirting my Cores:

A cut lead wire core, ready to go up into the squirt die with my squirt punch. I cut my lead wire 3gr. heavier than the squirted cores need to be to assure consistency in each finished core. For example: 0.790" jackets average 22.1gr., so the finished core needs to be 43.9gr to make a bullet 66.0gr. That means the cut lead wire for 66gr. bullets needs to average 46.9gr.


A 50# spool of lead wire, going into my core cutter, where cut wire cores fall into the bucket. 

 


A couple of freshly squirted cores along with the extra lead that squirts out of the die. The lead is extrude through three 0.03200" holes in the die and breaks into small pieces as it falls into the box under the die. You want 2.9 to 3.1 grains of extruded lead to squirt out to assure that the finished core is the correct weight. For a perfect bond with the copper, each core is degreased with Axarel 2200 prior to being inserted into a precision jacket.


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A tray of loaded jackets ready to be seated as either flat base or boat tail base, depending on which die I choose to use. 

A tray full of jackets with a lead core above each one. When I pull out the plexiglass sheet between these two trays the lead falls down into each jacket.

A tray of jackets ready to accept their lead cores.  Each tray holds 200 jackets/bullets.

A jacket loaded with a core, mounted on the punch, ready to go into the flat base seating die. The boat tails are formed the same way but I use a different die with the boat tail shape  inside the die.

The same jacket coming out of the die just before it falls into the magnetic box. Note the jackets in the box showing the lead compressed under approximately 80,000 psi.

Pointing up my bullets: 

A flat base, seated jacket going into the  point up die. Notice the two finished 66 grain bullets already in the magnetic box below it.

The same seated jacket, which has had it's ogive formed in this die, and just before it falls into the box as a finished flat base bullet.

After I point up my bullets, (and tip up my low drag bullets), I check a bullet from each tray with a Sinclair quick bullet sorting tool to assure that the base to ogive dimension is the same from bullet to bullet. I set my tolerance indicators for + .002". If I start seeing finished bullets falling out of specs., I know to check for wear in the links and pins of my presses, and exchange worn parts with factory new parts.

Quality Control through Precision Metrology:

As part of my commitment to accurate metrology, I have replaced my inexpensive analog Lyman micrometer, which reads with the resolution of 0.0005" and has the accuracy of 0.001", with a brand new expensive digital Mitutoyo micrometer which reads with the resolution of 0.00005" and has the accuracy of 0.00005".
It really validates just how perfect the internal measurements of all my carbide Detsch dies really are! I'm extremely proud to add this fine instrument to my work bench!

The pressure ring is 0.24350".

The bearing surface is 0.24300".

This is my Hoover Tipping Die that I use to close the meplats of my 6mm low drag bullets, custom as ordered, from 0.060" to about 0.005"!

Most bullet makers use only 2-3 seating punches, a flat base and a boat tail punch. I employ 39 punches in my operation to ensure everything has a proper fit.

I had this piece of stainless steel milled by Curt at CTK Precision for the ram, as Redding rams are over-sized because they are heavier-duty than RCBS and other presses.

6mm low drag bullet coming out of the tipping die.

6mm low drag bullet going into my tipping die.

Just above the pressure ring measures 0.24330".

My new shop in Nevada always kept at a constant temperature (77°) and humidity (26%):

I use my RCBS electronic scale when I gross-weigh components to a tenth (0.1gn.) of a grain, and I fine-weigh components  to the hundredth (0.01gn.) of a grain on my jeweler's electronic scale when I really need the exact weight for weighing swage lube and setting my dies. I also use stainless steel medical forceps with polyethylene covered tips, to prevent putting any marks on the bullets.









I've built this, my fourth shop, with extremely heavy stainless steel workbenches, Redding presses and Detsch dies, and several more accurate tools than I had in my earlier shops.

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Bearing Surface Quality Control:

Tipping up my VLD Meplats:

Seating my Cores.

Traying up my bullets.

I wear powder-free nitrile medical gloves during every process in building your bullets, to ensure that zero dirt or corrosion-causing contaminates ever touch them.

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