November 4th, 2016

Mysteries Revealed — How Cartridge Brass is Made

deep draw cartridge brass animated gif
Deep-Draw Ram Illustration from Demsey Mfg.

When we first ran this story a while back, it generated great interest among readers. By popular request, we’re reprinting this story, in case you missed it the first time around. — Editor

Rifle cartridge brass manufacturingPrecision shooters favor premium brass from Lapua, Norma, or RWS. (Lake City also makes quality brass in military calibers.) Premium brass delivers better accuracy, more consistent velocities, and longer life. Shooters understand the importance of good brass, but many of us have no idea how cartridge cases are actually made. Here’s how it’s done.

The process starts with a brass disk stamped from strips of metal. Then, through a series of stages, the brass is extruded or drawn into a cylindrical shape. In the extrusion process the brass is squeezed through a die under tremendous pressure. This is repeated two or three times typically. In the more traditional “draw” process, the case is progressively stretched longer, in 3 to 5 stages, using a series of high-pressure rams forcing the brass into a form die. While extrusion may be more common today, RWS, which makes some of the most uniform brass in the world, still uses the draw process: “It starts with cup drawing after the bands have been punched out. RWS cases are drawn in three ‘stages’ and after each draw they are annealed, pickled, rinsed and subjected to further quality improvement measures. This achieves specific hardening of the brass cases and increases their resistance to extraordinary stresses.” FYI, Lapua also uses a traditional draw process to manufacture most of its cartridge brass (although Lapua employs some proprietary steps that are different from RWS’s methods).

RWS Brass Cartridge Draw process

After the cases are extruded or drawn to max length, the cases are trimmed and the neck/shoulder are formed. Then the extractor groove (on rimless cases) is formed or machined, and the primer pocket is created in the base. One way to form the primer pocket is to use a hardened steel plug called a “bunter”. In the photos below you see the stages for forming a 20mm cannon case (courtesy OldAmmo.com), along with bunters used for Lake City rifle brass. This illustrates the draw process (as opposed to extrusion). The process of draw-forming rifle brass is that same as for this 20mm shell, just on a smaller scale.

20mm cartridge brass forming

20mm Draw Set Oldammo.com

River Valley Ordnance explains: “When a case is being made, it is drawn to its final draw length, with the diameter being slightly smaller than needed. At this point in its life, the head of the draw is slightly rounded, and there are no provisions for a primer. So the final drawn cases are trimmed to length, then run into the head bunter. A punch, ground to the intended contours for the inside of the case, pushes the draw into a cylindrical die and holds it in place while another punch rams into the case from the other end, mashing the bottom flat. That secondary ram holds the headstamp bunter punch.

Lake City Brass bunter

The headstamp bunter punch has a protrusion on the end to make the primer pocket, and has raised lettering around the face to form the headstamp writing. This is, of course, all a mirror image of the finished case head. Small cases, such as 5.56×45, can be headed with a single strike. Larger cases, like 7.62×51 and 50 BMG, need to be struck once to form a dent for the primer pocket, then a second strike to finish the pocket, flatten the head, and imprint the writing. This second strike works the brass to harden it so it will support the pressure of firing.”

Thanks to Guy Hildebrand, of the Cartridge Collectors’ Exchange, OldAmmo.com, for providing this 20mm Draw Set photo. Bunter photo from River Valley Ordnance.

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November 4th, 2016

The Rimfire Wheelgun — Why You Really Need One

Smith Wesson 22 .22 LR Revolver model 63 17 617 wheelgun revolver cylinder

“But Honey, I really do need a new gun….”

If you are looking for justification for getting a new handgun, show your spouse this article. Today we explain why every serious shooter should have a .22 LR wheelgun. Rimfire revolvers are versatile, reliable, easy-to-operate, and fun to shoot. A good .22 revolver will be considerably more accurate than 90% of the self-loading pistols you could buy. With a good a .22-caliber rimfire revolver you will learn sight alignment and trigger control. Plus you can practice with inexpensive ammunition.

The better .22 LR revolvers also hold their value. In particular, a Smith & Wesson model 617 (or its predecessor, the Model 17, shown below) is a good investment. You could use your S&W wheelgun all your life and then pass it on to your kids. If you or your heirs ever wear out the barrel or cylinder, Smith & Wesson will replace the parts for free, forever. Think about that…

Smith Wesson 22 .22 LR Revolver model 63 17 617 wheelgun revolver cylinder

The Model 63 Kit Gun is a compact 6-shot (older) or 8-shot (newer) revolver. Older Model 63s are in high demand, so this is another Smith wheelgun that holds its value well…

Smith Wesson 22 .22 LR Revolver model 63 17 617 wheelgun revolver cylinder

Smith Wesson model 617 4 inchSmith & Wesson Model 617 — Smith’s model 617 is extremely accurate, with a very crisp trigger (in single-action mode), and good sights. You can learn all the fundamentals with this ultra-reliable handgun, shooting inexpensive .22 LR ammo. The model 617 is rugged, durable, and can give you a lifetime of shooting fun.

Once you have mastered the basics of shooting with a .22 LR, you can move on to larger caliber handguns suitable for self-defense. Below is a slide-show illustrating a S&W model 617 ten-shot, with 6″ barrel. S&W also makes a 4″-barrel version of this revolver. (See: Shooting Demo Video with 4″ model 617.)

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