If you own or plan on shooting one of these carbines, it is safety imperative you read the last section on this page regarding Known Issues with the receivers used by Erma's Firearms Manufacturing.
Keep in mind that Erma's sold finished receivers with nothing else attached, for owners or companies that wished to build their own. As a result, barrels on the Erma's receivers may not be the barrels actually used or sold by Erma's.
With the exception of receivers, barrels were the most difficult surplus GI part to obtain, and one of the first to become unavailable. Many of the surplus GI barrels were cut in half by U.S. Ordnance (demilitarized aka demilled) and sold to scrap metal dealers. Prior to locating a steady reliable source for commercially manufactured barrels, most companies making carbines 1960-1963 had to devise a means by which to make their own.
To understand what Erma's and other companies did to manufacture barrels, a brief overview of barrels for the M1 Carbine is necessary.
.30 caliber carbine barrels used by the original GI contractors had a number of small variations, but the gas cylinder was basically built in one of two ways. Underwood, IBM, and Marlin manufactured the entire barrel, gas cylinder included, from one piece of steel. These barrels are referred to as having an integral gas cylinder. The rest of the manufacturers used a swaged on gas cylinder. The commercially manufactured barrels used by Erma's Manufacturing were based on the outer appearance and dimensions of the GI barrel with the swaged gas cylinder.
Barrels demilled by the government were cut into two pieces with the cut being made forward of the gas cylinder. By obtaining the rear half, manufacturers did not have to manufacture the gas cylinder, thread the barrel to fit the receiver, and in most cases were able to retain the barrel skirt at the breach end of the carbine barrel. Proper threading of the barrel and receiver is critical to proper and safe function of a gas operated semi-automatic carbine and required special machinery. The barrel skirt aids in guiding the bullet from the magazine into the chamber.
Erma's removed the swaged gas cylinder and cut the rear half of the barrel off inside the gas cylinder area. They then bored out the rear half to accommodate an insert.
While .30 caliber carbine barrels were demilled and recycled by the government, 1903A3 barrels were usually sold in bulk at government auctions and readily available at low prices.
The 1903A3 barrel has a groove diameter of .3095 and a land diameter of .3015. The later GI .30 caliber carbine barrels had a groove diameter between .308-.310 and a land diameter of .300-.302. Earlier carbine barrels were slightly tighter. This allows the .30 caliber carbine bullet to function properly in a 1903A3 barrel without having to change the inside dimensions. [The Model 1903 Springfield Rifle and it's Variations by Joe Poyer, 2nd Edition, revised][The U.S. .30 cal. Gas Operated Carbines, A Shop Manual, by Jerry Kuhnhausen]
All GI carbine barrels have 4 lands and grooves. Some of the 1903A3 barrels have four lands and grooves, others have two lands and grooves. The .30 caliber carbine functions in both. The difference in accuracy is debatable but the nature of the M1 Carbine is a close support weapon, not a sniper rifle. Most people wouldn't notice a difference due to the number of other factors that are more critical to the accuracy of each carbine.
For use as an M1 Carbine barrel, the surplus 1903A3 barrel was cut to the length of a carbine barrel, measuring from the muzzle rearward. This removed the .30-06 chamber from the barrel. The part of the 1903A3 barrel that slid inside the rear half of the bored out carbine barrel was cut down to a tight fit and inserted into the outer sleeve made from the carbine barrel. The two barrels were joined together by various methods, Erma's manufacturing most often created a pin that inserted through one side of the swaged gas piston housing and through both barrels (see pic below). Some were also silver soldered together. The chamber was then reamed for the .30 caliber carbine cartridge.
cutaway allowing view of 1903A3 barrel inside .30 caliber carbine barrel
Notice the pin through the swaged gas piston housing is visible directly above the ROC in ROCK-OLA
One of the challenges that can present is these barrels can look exactly like an M1 Carbine barrel manufactured under contract to U.S. Ordnance during WWII, with the exception the normal barrel manufacturer marking is absent. Yet, they retain any GI manufacturer markings or U.S. Ordnance markings on the gas piston housing and the carbine half of the barrel.
Clues to identifying a 1903A3 barrel used inside a .30 caliber carbine barrel (without trying to dismantle the barrel):
downturned area on muzzle end exceeds 1.6"
A variation of the same theme, with an extra support ring coming out from under the front of the swaged gas piston housing (note seam)
Barrel skirt has been ground down, 1903A3 barrel runs around the breech even with the inside of the barrel skirt.
Notice condition of receiver metal around breach. This will be discussed further below, under Known Issues with the Erma's Manufactured carbines.
A Note about safety. Anyone familiar with barrel manufacturing would rightfully criticize this method of making barrels. Logic would follow that they are inherently unsafe. Not necessarily true. Thousands of barrels were manufactured by various companies using variations of what is shown above, many of which ended up on GI M1 Carbine receivers in addition to carbines manufactured by National Ordnance, Alpine, Millville Ordnance, Plainfield Machine, and H&S. As commercially manufactured barrel blanks became available, all but Erma's Manufacturing switched to a different barrel. When in doubt, get the barrel inspected by a gunsmith. Don't even consider sacrificing safety, that might be someone's other than yours.
Erma's Manufacturing used surplus GI parts on their carbines as long and as often as they could get them at a competitive price. Two parts they at some point switched to manufacturing cast replacements for, were the hammer and trigger housing. To their credit, they marked both of these with the letter E in a distinctive font and size used only by Erma's Manufacturing. These two parts are easily distinguished as something not done by any company who manufactured carbine parts under contract to U.S. Ordnance. Unfortunately, Plainfield Machine was the only other company to do this (but not consistently like Erma's).
Distinctive font with single letter E identifies Erma's/Steelville Mfg. hammer and/or trigger housing
Most or all of the stocks and handguards used by Erma's Firearms Manufacturing were made from walnut by S.E. Overton in Michigan. Overton manufactured stocks and handguards for the Inland Division of General Motors during WWII with the letters OI, often observed as IO, inside the stock slingwell or under the handguard. Stocks Overton manufactured for various commercial carbine manufacturers do not have these initials, which were assigned by U.S. Army Ordnance as a means of quality control. The Overton stocks used by Erma's were designed equivalent to the GI stocks known as M2 "pot belly" stocks. The M2 stocks fit M1 Carbines. The stocks Overton manufactured for Erma's are some of the nicest stocks manufactured for or by any commercial carbine manufacturer.
Shotgun News issues between February and June 1964 show Erma's Manufacturing of Steelville, MO advertisements for M1 Carbine parts and receivers. The last issue of Shotgun News that an Erma's Manufacturing ad appeared in was June 15, 1964.
Missouri corporate documents indicate that on July 23, 1964 the name of Erma's Firearms was changed by the Board of Directors to Steelville Manufacturing Company, Inc. The Chairman of the Stockholder's Meeting was Virgil E. Center, the Secretary-Treasurer was Paul Bell. Paul Bell was the attorney for Erma's Firearms when they incorporated in 1959. In another corporate document dated August 5, 1964 Virgil E. Smith is identified as President of Steelville Manufacturing Co., Inc.
Harold D. Tucker incorporated Johnston-Tucker Firearms in St. Louis, MO on August 5, 1965 and began producing .22 caliber M1 Carbines under the Johnston-Tucker name. Further information on Johnston-Tucker Firearms can be found on this website's page devoted to their company.
Beginning with the Shotgun News issue of September 15, 1964, continuing off and on until October 1, 1965, the earlier Erma's advertisements appear under the name of Steelville Manufacturing, "formerly Erma's Mfg".
After the name change to Steelville Manufacturing Erma's no longer sold complete carbines, only parts, barrels, and receivers. The ads indicate their receivers were manufactured from 4130 steel.
June 15, 1964
September 15, 1964
The October 15, 1967 issue of Shotgun News carried an advertisement by Steelville Manufacturing announcing a final clearance on the surplus left over from Erma's Firearms. A copy of the advertisement is being sought for inclusion in this page.
Missouri marriage records indicate Virgil Center married Madge Harman in Iron Co., MO on 23 Feb 1937. According Jim Dobkins, grandson of Virgil and Madge, his mother Sharon Center was their daughter and married Jim "Sunny" Dobkins, his dad. Jim Dobkins indicated his grandfather Virgil was a machinist at Erma's Firearms. Sharon Center and Jim "Sunny Dobkins met at Erma's Firearms where they were both employed as machinists. Sharon manufactured the .30 caliber carbine barrels from the Springfield 1903A3 barrels. One day her clothes were caught in a lathe and Jim "Sunny" Dobkins came to her rescue, eventually leading to their marriage.
As indicated on the previous page the three shareholders at the time Erma's Firearms incorporated were Harold D. Tucker, Raymond K. McConnell, and Arthur E. Pursley. Arthur Pursley died May 28, 1964. According to Jim Dobkins, Pursley died of a heart attack and his shares were purchased by Delmar Hudson. In 1964 Paul Bell purchased the controlling shares in Erma's, changed the name to Steelville Manufacturing and ceased M1 Carbine production. His grandfather Virgil had been a stockholder at the time. The company switched to manufacturing aircraft parts.
As of 2011 Steelville Manufacturing is still owned and operated by the Bell family. They manufacture various parts for the aerospace industry.
Three Erma's Manufacturing receivers have been hardness tested to date. The serial numbers range from 1300 to 1550. Using two separate Rockwell C scale testers, all three receivers tested less than 10. This is consistent with the receivers having never been hardened.
It is clear from the number of receivers observed that are bent and/or deformed around the breach and along the right side of the receiver between the bolt and slide, the receivers made and used by Erma's Manufacturing are consistent with having never been hardened. This is a serious safety issue. Over time the receiver will worsen until it fails completely. The deformity of the breach area can lead to improper headspace and catastrophic failure of the carbine during firing, which could include serious injury to the shooter and/or anyone nearby.
It is strongly recommended these receivers be inspected by a gunsmith before they are used. The gunsmith may determine the receiver can be hardened and refinished, rendering it safe to be used. He will need to know the receiver was cast from 4130 steel.
Catastrophic failure of an Erma's Manufacturing receiver typical of improper headspace, in this case the deformity indicates improper hardening
of the receiver which may have caused or contributed to improper headspace.
Same receiver, different angle