June 6th, 2019

Neck-Turning Brass on Milling Machine with Erik Cortina

cartridge brass neck turn neck-turning milling machine Erik Cortina

Here’s the super-speedy way to turn case-necks. Our friend Erik Cortina figured out how to turn his match cartridge case-necks using his milling machine. Erik told us: “While in Raton, Mid Tompkins told me that he turns his brass on milling machine. He said he could do about 500 in two hours, so I decided to try it.”

Erik fitted a Don Nielson “Pumpkin” neck-turner to the mill, and he used a modified 21st Century case holder to secure the brass. As you can see from this video, Erik was very successful with the process. The tool spins at 1500 rpm, turning Lapua 6.5-284 cases that have been necked up to 7mm.

Video Shows Eric Cortina Neck-Turning Cases with Milling Machine:

Cartridge Brass: Lapua 6.5-284 necked up to 7mm
Lubricant: Lithium grease inside and outside of neck
Neck-Turner: Nielson Pumpkin running at 1500 RPM

It’s hard to argue with Erik’s results. Here are his turned Lapua cases, which have neck-wall thickness consistent to two ten-thousandths of an inch. Think you could do better turning manually?

cartridge brass neck turn neck-turning milling machine Erik Cortina

Some of Erik’s Facebook friends had questions about this process:

Q: Who makes the shell-holder?

Erik Cortina: I did! The shell-holder you can get from 21st Century. I Tig-welded a punch as a handle.

Q: I love the idea of working smarter not harder! Any galling issues? What are your mitigation techniques?

Erik Cortina: No issues. I use lithium grease in spray can. Makes a foam that I dip necks into.

Q: Shouldn’t either the case or the cutter be floating to allow most precise neck turning?

Erik Cortina: Up until [I tried this] I believed the same thing. I was going to build a floating case holder but decided to try rigid setup on a few cases before I built it. Results were great. Neck thickness doesn’t vary more than .0002″, which is same as when I was doing it with floating case holder on the lathe.

Q: Any problems with the Pumpkin changing the cut as it heats up?

Erik Cortina: No — there were no issues with that.

NOTE: Erik Cortina is a very skilled machinist who custom-crafted fittings used for this process. This kind of neck-turning with a milling machine may not be for the everyday hand-loader!

cartridge brass neck turn neck-turning milling machine Erik Cortina

Nielson “Pumpkin” Neck-Turner

Don Nielson Pumpkin neck turning toolThe circular orange cutting fixture on Erik’s Milling Machine is a Don Nielson “Pumpkin” neck-turning tool. Don designed this tool to be used by hand or with power. The Pumpkin boasts an eccentric mandrel that allows the cut to be adjusted easily in precise .0001″ increments. Benchresters like this as it allows for very precise control of cut depth and neck-wall thickness.

Jason C., commenting on Erik’s YouTube video stated: “I have a couple of those too. Nothing cuts like a Pumpkin. [Don Nielson] made the best cutter tool ever.” These are still available if you ask around. The photo shows Don with a case-holder mounted to a power assembly. A talented machinist and tool-maker, Don has also been a successful short- and long-range benchrest shooter, who has won NBRSA 600-Yard Championships. CLICK HERE to read about Don’s success with the 6.5×47 Lapua.

cartridge brass neck turn neck-turning milling machine Erik Cortina
Nielson Neck Turner with carbide mandrel. Photo Courtesy Butch’s Reloading.

Similar Posts:

Tags: , , , , , , , , ,