Auto Mag Cartridges

Auto Mag Cartridges

March 1999

by Bruce Stark

Since the introduction of the .44 Magnum cartridge in 1956 there had been a desire by the shooting public for a semi-automatic version of this cartridge and a gun to shoot it. In the 1958 Summer edition of Guns and Ammo a .44 Automatic rimless cartridge was proposed. It had an overall length of 1.600″.

Harry Sanford’s plans to produce the Auto Mag handgun, using a .44 Magnum semi-automatic cartridge, were first revealed in an article contained in the March 1970 Guns and Ammo magazine. Harry’s new .44AMP (Auto Mag Pistol) cartridge had a 1.298″ case length and was the same overall length as the .44 Magnum, 1.610″. In the same article several other proposed cartridges are mentioned: the 9mm-44 Auto, .30-44 Auto and a .36-44 Auto.   There is talk in the article of reducing the .44AMP case length to 1.200″ but it never happened.

Auto Mag Corp., in Pasadena California, made up three barrels to test the new .357AMP cartridge. The case was produced by simply necking down a .44AMP case and reaming it to accept a .357 bullet. It proved very successful and was well hailed by all who tested it. The tapered cartridge helped in feeding and it seated on the shoulder which helped the accuracy.  The .357 bullets that were made at the time were not designed to work at the speeds that the Auto Mag could achieve. Sometimes the jackets were ripped off of the bullets and remained in the barrel. Before the company’s bankruptcy one barrel was made up to test the .30 caliber Auto Mag cartridge. It was named the .300AMP. It had a shoulder angle of 30 degrees. There were also five Auto Mags made up to fire .45ACP Hardball ammo.

During the North Hollywood production run of Auto Mags, .357AMP and .44AMP chambered Auto Mags were offered for sale.

For a period of time, during the El Monte days, Lee Jurras was the exclusive distributor of Auto Mags. In September of 1974 Lee introduced the .41JMP (Jurras Magnum Pistol) cartridge in a 1.610″ overall length. The .41JMP had a shoulder that was too shallow to seat on.  Like the .44AMP, the .41JMP seated on the mouth.

In the mid-seventies Kent Lomont created several wildcat calibers for the Auto Mag handgun. He also made unique barrels and scope mounts that Lee Jurras used on some of his custom guns. Kent offered custom barrels chambered in .22LMP (Lomont Magnum Pistol), .25LMP and .30LMP. The .30LMP had a 20 degree shoulder as opposed to the 30 degrees of the .300AMP cartridge. Kent also made custom barrels in .357AMP, .41JMP and .44AMP and gave them his own custom markings. He originally wanted to use different dinosaurs for the different calibers but he couldn’t find the artwork for it. He eventually used different animals for each of the calibers and had pictures of them electro etched on the receivers (barrel extensions).  Each animal represented an appropriate animal that could be shot with that caliber. Kent also experimented with a barrel chambered for the .45ACP Magnum. All of Kent Lomont’s Auto Mag cartridges were a 1.610″ overall length.

Kent’s animal designations are as follows;

.44AMP Bison Model 180
.41JMP Grizzly Model 170
.357AMP Antelope Model 160
.30LMP Cougar Model 150
.25LMP Fox Model 140
.22LMP Groundhog Model 130

Robert Barbasiewicz was the project engineer during the developmental period of the Auto Mag. In the early seventies he made up custom barrels in .44 and .357AMP. They were highly polished with no markings in 6.5″, 8.5″ and 10.5″ lengths with no rib. In 1979 the .45 Winchester Magnum cartridge was introduced for the Wildey handgun. The author and Ed O’Neil approached Harry Sanford about him making up some Auto Mag barrels to shoot it. Harry said no. We approached Bob Barbasiewicz and he agreed to make up ten 10.5″ barrels chambered in .45 Win Mag.

The .45 Win Mag cartridge had a case length of 1.198″ and an overall length of 1.575″. The shorter overall length adds to chambering problems. Any feeding problem results in the cartridge getting caught sideways in the receiver.

In July of 1980 the factory, AMT, made up two experimental .45ACP magnum barrels to test the .45ACP Magnum and .45 Win Mag cartridges. One barrel was 8.5″ and the other was 10.5″ long. When using Winchester .45 Win Mag ammo, it was determined that the barrel would have to be 10.5″ long in order to develop the velocities required to cycle the gun. When .45 Win Mag cartridges were shot in the .45ACP Magnum chambered barrel, case separations were quite common.

In October of 1990, Eric Kincel, a writer at Gun World magazine, and Brian Maynard, a technician working in the service department at AMT, came up with a new Auto Mag cartridge. It was the .40KMP (Kincel Maynard Precision). It used a 40 caliber bullet and seated on its 45 degree shoulder.  It had a shorter overall length of 1.600″.

In the first issue, November 1997, of George Hebert’s The Auto Mag Newsletter, there is a picture of an Auto Mag chambered to shoot a .475 bullet. It was also made by Brian Maynard.

1) .45ACP
2) .44AMP
3) .357AMP
4) .300AMP
5) .41JMP
6) .30LMP
7) .25LMP
8) .22LMP
9) .45ACP Magnum
10) .45 Win Mag
11) .40KMP
12) .475 Auto Mag

Most Auto Mag shooters have found that the .357AMP with an 8.5″ barrel is the best caliber and barrel length combination for the Auto Mag. Kent Lomont likes the .30LMP with a 10.5″ barrel. Getting the smaller calibers to cycle the gun has always been a challenge. Modified accelerators, lightened barrels and heavy bullets will usually get the gun cycling OK.

There have also been some shot-shell cartridges made for the Auto Mag.  They usually have to be fed through the ejection port and will not cycle the gun.  The CLINT-2- gun that was used in the movie “Sudden Impact” was modified to shoot blank cartridges of custom manufacture.

 

Auto Mag Cartridges — March 1999

by Bruce Stark

Since the introduction of the .44 Magnum cartridge in 1956 there had been a desire by the shooting public for a semi-automatic version of this cartridge and a gun to shoot it. In the 1958 Summer edition of Guns and Ammo a .44 Automatic rimless cartridge was proposed. It had an overall length of 1.600″.

Harry Sanford’s plans to produce the Auto Mag handgun, using a .44 Magnum semi-automatic cartridge, were first revealed in an article contained in the March 1970 Guns and Ammo magazine. Harry’s new .44AMP (Auto Mag Pistol) cartridge had a 1.298″ case length and was the same overall length as the .44 Magnum, 1.610″. In the same article several other proposed cartridges are mentioned: the 9mm-44 Auto, .30-44 Auto and a .36-44 Auto.   There is talk in the article of reducing the .44AMP case length to 1.200″ but it never happened.

Auto Mag Corp., in Pasadena California, made up three barrels to test the new .357AMP cartridge. The case was produced by simply necking down a .44AMP case and reaming it to accept a .357 bullet. It proved very successful and was well hailed by all who tested it. The tapered cartridge helped in feeding and it seated on the shoulder which helped the accuracy.  The .357 bullets that were made at the time were not designed to work at the speeds that the Auto Mag could achieve. Sometimes the jackets were ripped off of the bullets and remained in the barrel. Before the company’s bankruptcy one barrel was made up to test the .30 caliber Auto Mag cartridge. It was named the .300AMP. It had a shoulder angle of 30 degrees. There were also five Auto Mags made up to fire .45ACP Hardball ammo.

During the North Hollywood production run of Auto Mags, .357AMP and .44AMP chambered Auto Mags were offered for sale.

For a period of time, during the El Monte days, Lee Jurras was the exclusive distributor of Auto Mags. In September of 1974 Lee introduced the .41JMP (Jurras Magnum Pistol) cartridge in a 1.610″ overall length. The .41JMP had a shoulder that was too shallow to seat on.  Like the .44AMP, the .41JMP seated on the mouth.

In the mid-seventies Kent Lomont created several wildcat calibers for the Auto Mag handgun. He also made unique barrels and scope mounts that Lee Jurras used on some of his custom guns. Kent offered custom barrels chambered in .22LMP (Lomont Magnum Pistol), .25LMP and .30LMP. The .30LMP had a 20 degree shoulder as opposed to the 30 degrees of the .300AMP cartridge. Kent also made custom barrels in .357AMP, .41JMP and .44AMP and gave them his own custom markings. He originally wanted to use different dinosaurs for the different calibers but he couldn’t find the artwork for it. He eventually used different animals for each of the calibers and had pictures of them electro etched on the receivers (barrel extensions).  Each animal represented an appropriate animal that could be shot with that caliber. Kent also experimented with a barrel chambered for the .45ACP Magnum. All of Kent Lomont’s Auto Mag cartridges were a 1.610″ overall length.

Kent’s animal designations are as follows;

.44AMP Bison Model 180
.41JMP Grizzly Model 170
.357AMP Antelope Model 160
.30LMP Cougar Model 150
.25LMP Fox Model 140
.22LMP Groundhog Model 130

Robert Barbasiewicz was the project engineer during the developmental period of the Auto Mag. In the early seventies he made up custom barrels in .44 and .357AMP. They were highly polished with no markings in 6.5″, 8.5″ and 10.5″ lengths with no rib. In 1979 the .45 Winchester Magnum cartridge was introduced for the Wildey handgun. The author and Ed O’Neil approached Harry Sanford about him making up some Auto Mag barrels to shoot it. Harry said no. We approached Bob Barbasiewicz and he agreed to make up ten 10.5″ barrels chambered in .45 Win Mag.

The .45 Win Mag cartridge had a case length of 1.198″ and an overall length of 1.575″. The shorter overall length adds to chambering problems. Any feeding problem results in the cartridge getting caught sideways in the receiver.

In July of 1980 the factory, AMT, made up two experimental .45ACP magnum barrels to test the .45ACP Magnum and .45 Win Mag cartridges. One barrel was 8.5″ and the other was 10.5″ long. When using Winchester .45 Win Mag ammo, it was determined that the barrel would have to be 10.5″ long in order to develop the velocities required to cycle the gun. When .45 Win Mag cartridges were shot in the .45ACP Magnum chambered barrel, case separations were quite common.

In October of 1990, Eric Kincel, a writer at Gun World magazine, and Brian Maynard, a technician working in the service department at AMT, came up with a new Auto Mag cartridge. It was the .40KMP (Kincel Maynard Pistol). It used a 40 caliber bullet and seated on its 45 degree shoulder.  It had a shorter overall length of 1.600″.

In the first issue, November 1997, of George Hebert’s The Auto Mag Newsletter, there is a picture of an Auto Mag chambered to shoot a .475 bullet. It was also made by Brian Maynard.

1) .45ACP
2) .44AMP
3) .357AMP
4) .300AMP
5) .41JMP
6) .30LMP
7) .25LMP
8) .22LMP
9) .45ACP Magnum
10) .45 Win Mag
11) .40KMP
12) .475 Auto Mag

Most Auto Mag shooters have found that the .357AMP with an 8.5″ barrel is the best caliber and barrel length combination for the Auto Mag. Kent Lomont likes the .30LMP with a 10.5″ barrel. Getting the smaller calibers to cycle the gun has always been a challenge. Modified accelerators, lightened barrels and heavy bullets will usually get the gun cycling OK.

There have also been some shot-shell cartridges made for the Auto Mag.  They usually have to be fed through the ejection port and will not cycle the gun.  The CLINT-2- gun that was used in the movie “Sudden Impact” was modified to shoot blank cartridges of custom manufacture.