Big bangs & big bucks
. We look at the- production techniques of two firearms builders, one a high-volume manufacturer and the other low volume.
You could call them beauty and the beast. One offers old-world craftsmanship in a competition-grade shotgun with a price approaching $-70,000 per copy or more. The other is a 50caliber target/sniper rifle that has guaranteed accuracy to put a group of shots within a 10″ (254 mm) circle at 1000 yards (914 in). Modern manufacturing techniques play a large part in the production of both firearms.
As the oldest industrial company in the world, with roots going back 475 years, Beretta (Accokeek, MD) makes shotguns, rifles, pistols, knives, sporting apparel, and accessories. They currently supply the US military with a 9-mm semiautomatic pistol the Model M9 (commercial designation 92FS).
To manufacture a gun, Beretta buys 7075 T6 aluminum, a proprietary stainless steel, and titanium forgings for the pistol frames, and 8640 steel and a proprietary stainless bar stock for the barrels, and machines the components in-house. “Basically, the company builds firearm frames, receivers, barrels, and slides,” says Bill Lutton, engineering manager. “Rifle barrels are bought from the parent company in Italy, because of the specialized forging equipment needed to make them. Italy does all the barrel work for all the companies it owns.” In Italy, the company has seven GFM Hammer-Forge machines for this type of work. Pistol barrels for US guns are made in the Maryland plant.
A very important factor in producing the precision that the company demands for each firearm is the machining center workholding fixture. Lutton says that fixtures are built in-house because of their complexity, and the part tolerances they must hold. Most are hydraulically controlled, and fixture more than one part. “Firearm tolerances are extremely precise, and we feel few outside companies can build a custom fixture to handle these parts,” he explains.
Beretta even has its own Walther five-axis CNC cutter-grinder to produce high-speed-steel form-cutting tools. There are a lot of intricate cuts on the firearms that require these types of tools. They also use the grinder to sharpen broaches and gundrills.
The frame of a large-caliber pistol starts out as a 7075 T6 aluminum forging with an 8640 steel forging for the slide and steel rectangular bar stock for the barrel. For small pistols, the frame starts out as an aluminum or titanium casting, and the slide and barrel are alloy-steel bar stock. Cutting titanium wasn’t nearly the challenge they thought it would be, but the company is not marketing a firearm made entirely of titanium. “We worked with a casting vendor who did a wonderful job casting the frames for the guns in titanium. So we designed them, and cast in far more features than we do for aluminum to reduce the amount of machining,” says Lutton.
Much of the production equipment Beretta US uses is very specialized, comes from Italy, and is no longer in production. So maintenance can be a bit of a challenge. The shop is adding two new Mitsui Seiki highspeed four-axis CNC horizontal machining centers, and retiring some of their older equipment.
To enhance part quality and eliminate a multitude of hand gages, Beretta uses nine CMMs located through– out the production floor. These machines are seamlessly integrated into production to guarantee precision parts, and a stable machining process. Before acquiring the CMMs, Beretta had roughly 7000 gages for checking critical dimensions. “This situation was prohibitive because now we had to calibrate all these gages, and then spend a lot of money to maintain them,” says Lutton. “If you have 44 gauges on the table in front of the machinist, there’s no guarantee that he will use any of them, let alone the ones that he needs to use. If you decrease the frequency of part checks, than it is easier for them to do quality checks,’ he adds.
With the CMMs, Beretta makes their machinists responsible for tracking part quality. Each machinist loads in the proper program on the CMM for checking the parts, checks them, and makes adjustments to the machine if the parts are out of tolerance. A readout of the part’s dimensions produced by the CMM must be submitted to management. This checking process guarantees that parts are being checked properly, in a timely sequence, and machine tolerance corrections are being made if needed. “With Beretta there is no middle-of-the-road quality; either its absolutely correct or it’s scrap,” says Lutton.
Beyond their specialized machining equipment, Beretta also uses Chiron and Haas VMCs. “The newer CNC equipment gives us flexibility to change models and parts, and keep the specialized technology, for the difficult cuts,” adds Lutton. VMCs are set up and programmed to do various parts and operations. One operator is used for four CNC machines. Fixtures are designed to either minimize or eliminate burrs on the gun components, which frees-up the operator for other work instead of requiring him to manually deburr parts.
Beretta also has complete heat-treating facilities for their firearms using both vacuum furnaces and induction hardening. For corrosion resistance, Beretta has lines for phosphating, chroming, and plating. All aluminum parts are anodized, and government firearms are phosphated.
To do the barrel rifling for their handguns, Berretta uses a button broach for small-caliber short barrels and a standard broach for the 9-mm and 40-caliber pistols. A button broach doesn’t cut the rifling inside the gun’s barrel, it squeezes it into the barrel. A standard broach cuts the rifling into the barrel. Rifling is not a simple operation, according to Lutton. “You need an accurate, gundrilled hole size in the product, a property ground and hardened broach made from the correct steel, the right broach speed, the correct sequence of cutting, and then it’s a piece of cake.”
Once the gun is completed, rollmarkings and engravings are done if needed. The company also uses a YAG laser to engrave designs for individuals and police departments and also does hand engraving. Sometimes laser engraving is 24-carat gold-filled or nickel plated. Beretta’s manufacturing engineers find that using a laser is a lot easier than roll marking numbers or a design. Using a computer with a scanner and laser has allowed Beretta to scan a quality piece of artwork and laser– engrave it onto a gun in a matter of seconds rather than hours. After packaging, and prior to shipping, the firearm’s serial numbers are checked and tracked to meet government regulations.
What are the differences between a Beretta fieldgrade gun and a premium one? Beretta’s Garbiele de Plano says that wood quality, engraving, and the finish on receivers and barrels are the main points of distinction. Most of the company’s firearms use the same internal parts, but the premium guns have some unusual features. Gun costs increase as more labor and hand craftsmanship go into engraving and finishing. The highest-end premium guns do have a sidelock that contains part of the trigger mechanism, and is removable. When these shotguns are hand engraved (and depending on the complexity of the engraving), the gun’s price can increase tremendously. On the less-expensive Beretta guns, the sidelock is just a cover plate. Competition guns also have adjustable features such as the trigger, different sighting beads, and various barrel rib configurations. Barrel quality, however, is the same for all guns whether they are meant for high or low usage. All guns have removable hinge pins that allow the locking action to be brought back to its original state after high use. They also have replaceable conical locking lugs that engage the barrels and wear to keep the gun barrel in alignment.
“New product development is pretty typical at Beretta,” says Lutton. “A request is received from the marketing department with specific product guidelines. We turn the specifics over to a designer who comes up with a concept, and we discuss if it’s the right approach. Then we develop the design into workable drawings so we can create part prototypes. Computer drawings are done on a Unigraphics system.Then we use stereolithography for the prototype parts. This helps us develop the parts and the gun before we spend a great deal of money on tooling. With the prototypes built, we test them, refine the designs, and then turn them back over to marketing. A few more changes will usually result from this. During the prototype process, we start to review the tooling we need to produce the firearm. By the time marketing releases the design, we have the tooling. At this point, we’re also sending out drawings to the casting or forging vendors.” Lutton said that the forging and casting vendors usually want changes that the company tries to get upfront, so the design remains as original as possible. Sometimes vendors will even make radical changes. For instance, they might want to put very visible parting lines or a gate in the casting, which detracts from the gun’s finish. So while the vendors work out these issues, the company builds tooling and prepares for production.
“During prototype work, we always have to look at the nuts and bolts of the manufacturing process,” adds Lutton. “For instance, do we have the machines available, how many parts can we get on a machine, and do we have the capacity needed to produce all the parts for finished guns? We also have to look at cell design to produce the parts efficiently. All of this goes on concurrently. Also, we might have to order new equipment. After all the parts are produced, and new guns assembled, we do extensive testing. We have to meet government and state regulations, industry standards, and our own standards for the new model. We usually need from 30 to 50 pilot firearms to get through this stage. A timeline for initial design to finished product is usually about six months. An average, however, is about two years to get a new firearm to market,” says Lutton.
The Beretta factory produces about 1500 firearms per day in factories in both Italy and the US. The US factory encompasses 140,000 ft^sup 2^ (13020 m^sup 2^) of combined manufacturing space. Their firearms are well known throughout the world, and are used for competitive shooting in the Olympics, and often become family heirlooms. “We have people that bring guns to us for service or refurbishment that are 100-years old, having been passed along several generations. We try to do our best servicing them, but sometimes parts are just not available,” says de Plano.
In the US, the company assembles large and small-frame pistols and rifles. Beretta produces pistols in 22, 25, and 32 caliber, and large frame pistols in 9 mm and 40 caliber. Shotguns are available in 12, 28, 20, and 410 gauges. In the future, they’ll produce a new 22LR plinker pistol and new shotguns.
To make sure a customer is getting a quality firearm, each is assembled, test fired, disassembled, cleaned, and reassembled before packaging for final sale. For test firing, the company uses what they call a snail, a spiral containment compartment filled with water. The water slows the bullet, which falls out the bottom of the unit after going around the spiral.
On the other side of the US, E.D.M. Arms (Redlands, CA) builds a very accurate takedown 50-BMG caliber bolt-action target/sniper rifle. The company builds only about 110 guns per year, and has increased production yearly as they become known in the marketplace. BMG means Browning Machine Gun, because these target rifles use the same cartridge as the Browning.
About 12 years ago, Keary Ritchie, president, began manufacturing firearms with his father, Bill, both are target shooters. At the time, Keary had a job shop that did EDM diesinking and specialized in stamping dies. A product for the job shop would help them pay the bills, and fill-in during slow times.
After experimenting with a 50– caliber design, Ritchie produced a bench rest gun, then developed a bolt-action design using a takedown concept, which means that the gun’s barrel is removable and the shoulder rest is collapsible. By using the best of other company’s designs, and marrying them in one rifle for sport and target shooting with a detachable and replaceable barrel, the company developed a unique design that retails for $7250.
Available in three calibers, 338, 408, and 50, the rifle starts out as a 4140 Chromoloy steel billet. A Haas HS-1 horizontal machining center with a 60-tool changer and 30-hp (22.4-kW) spindle is used to machine the billet into a receiver, the job takes 10 hours, and the HMC runs two shifts a day.
Receivers are mounted on two faces of a four-sided tombstone using hard fixturing. One side uses a vise with one receiver blank fixtured for cutting. On the opposite side of the tombstone (1800 away), two receivers are fixtured for cutting. The other two tombstone faces are used for other parts.
After the receiver is machined, it’s heattreated and EDM cut, which requires another 10 hours. The EDM work gives the receiver a precise fit, and allows the bolt to slide easily in the receiver. This step sets the WindRunner gun apart from others that are similar, says Ritchie. If the bolt doesn’t move easily in the receiver, and you get some debris or adverse temperature variations in the area, the rifle can jam. “If you make the receiver/bolt area too tight, after thermal expansion caused by firing, they stop working. So this is a very critical area,” Ritchie adds.
There are 50 different components to the rifle, not counting 30 different fasteners. Most of these are machined on the company’s CNC machining centers and EDM machines. They even chamber the barrels automatically on the machining centers to ensure a precise chamber and head-spacing. The chamber depth has to be within precise tolerances for the barrels to be exact and interchangeable.
The final dimension, where the barrel slides into the receiver, is ground to -0.001″ (0.02 mm). Receivers are honed to a plus 0.001″ (0.02 mm) minus nothing after heat-treating and wire-cutting. This specification allows no more than a 0.002″ (0.05-mm) clearance. However, the actual clearance is less, because the company stays on the minimum side. Ritchie said that they could hold even tighter tolerances, but the guns would not disassemble in climates that experience extreme temperature cycles. Other gun parts are made from investment castings, stamping dies, and rubber molds. Barrel blanks are bought from an outside supplier, and are ground, machined, and chambered to hold a precise cartridge depth. Then they are fluted along their length, threaded for the muzzle break, ground to +/- 0.001″ (0.02 mm), and hard-chromed to R^sub c^ 60.
Keary said they are working on a super lightweight model that weighs only 22 lb (9.9 kg) versus a 35 lb (15.75 kg) normal weight. At the lighter weight, Keary fears that the gun will have a tremendous kick.
They are currently trying to get the US military to buy their gun as a sniper weapon. Other countries like Canada, Mexico, and Turkey are reviewing it for their armies.
Want More Information?
Circle these numbers on the reader service card for more details on the equipment mentioned in this article.
EDM Arms ………………………361
Copyright Society of Manufacturing Engineers Oct 2001
Provided by ProQuest Information and Learning Company. All rights Reserved