What You Need to Know About Parts

There is only one standard for the dimensions, machining, quality, and life span of every part on an M1 Carbine. The standard adopted by U.S. Army Ordnance for the U.S. .30 caliber carbines M1, M1A1, M2, and T3. There is no other standard. Ordnance standards were established based on research and development, testing, field use of the carbines during WWII, and more. These standards insured the parts were interchangeable between all of the U.S. GI carbines, regardless of manufacturer. They also set the requirements each part would have to meet to pass inspection, not only by the manufacturer but also by U.S. Army Ordnance inspectors assigned to the manufacturing facilities of each of the primary contractors making carbines. If a manufacturer didn't get it right, it didn't go out the door on a finished carbine. If a manufacturer consistently and repeatedly didn't get it right they risked losing their contract.

Almost all of the post war commercial carbine manufacturers started out using as many of the surplus GI carbine parts as they could get. As the availability of each part dried up, each commercial manufacturer made, or subcontracted to be made, a commercially manufactured part that would fill the role of it's GI counterpart. While these commercially manufactured parts may have been dimensionally the same as a GI part, none of them were manufactured using the standards established by U.S. Army Ordnance. The new "standard" became whatever "worked" and was cost efficient. How well it worked and for how long was/is nowhere near the quality and lifespan of any of the parts manufactured for U.S. Ordnance. Commercial manufacturers could get by with parts that didn't meet the standards of U.S. Ordnance as their carbines were mostly made for the average citizen during peace time, not soldiers subjecting their carbines to conditions common during a war.

If a commercial carbine and it's parts were manufactured to GI dimensions, then they were "GI compatible", meaning they could be interchanged with all other parts manufactured to GI dimensions, including the surplus GI parts. Most, but not all, commercial carbine manufacturers attempted to stick to these dimensions and interchangeability. Some did it better than others.

Buying a Replacement Part

The first thing you need to determine is if the part you want to replace is "GI compatible". The table below lists the commercial carbine manufacturers and identifies which ones made carbines that have "GI compatible" parts.

If a carbine is indicated as less than 100% "GI compatible", read the web page for that particular manufacturer.

If a carbine and it's parts are GI compatible, the best replacement part is one that was manufactured for U.S. Army Ordnance (surplus GI parts-see bottom of page). There are plenty still available and still in very good condition with many years of service left in them. If the cost is above what you want to pay for a part, the commercially manufactured parts are an option. Realize the quality control standards are an unknown. Most GI compatible parts will work. The questions is, how well and for how long. Most parts will wear out quicker and need to be replaced sooner than their GI equivalent would.

The following parts should be inspected occasionally and replaced before the wear becomes excessive. Parts followed by an asterisk (*) are safety critical parts you should seriously consider replacing with GI surplus parts instead of their commercial equivalents if your carbine's parts are GI compatible. A few commercial companies may have manufactured and hardened them to the high standards necessary for safety. The problem is knowing which commercial manufacture did and how to identify their parts from those who didn't. The markings used by U.S. Ordnance contracted companies for quality control served a purpose. Commercial equivalents rarely have identifiable markings. Testing each part requires equipment and expertise that is cost prohibitive.

• Bolt*
• Firing pin
• Extractor
• Extractor spring and plunger
• Hammer*
• Sear*
• Slide*

Where do I buy the parts I need?

I do not endorse retailers. There are plenty of other retailers, just do an internet search on what you want to buy and shop around. Gunbroker.com is an auction website with hundreds of sellers offering just about any part you would need. Like any other internet auction website, common sense and caution when dealing with people you don't know is advised. On the links page there are links to parts suppliers I have found to be honest and reliable.

Company	Link	GI Compatible? Parts	Notes
Alpine Industries Los Angeles, CA		100%
AMAC Jacksonville, AR		100%
American Historical Foundation Richmond, VA	Pending	100%
AMPCO Miami, FL		100%
Auto-Ordnance Worcester, MA		inconsistent	see web page
Bullseye Gun Works Miami, FL		100%
Crosman Air Guns Fairport, NY		no
Erma's Firearms Manufacturing Co. Steelville, MO		100%
ERMA-Werke Dachau, Bavaria		no
Federal Ordnance South El Monte, CA	Pending	100%
Global Arms		100%
H & S		100%
HOWA Nagoya, Japan		95%	rear sight & rear sight dovetail not GI compatible for commercial models refer web page
Israel Arms International (IAI) Houston, Texas		100%	.30 carbine is 100% compatible, for others refer to web page
Iver Johnson's Arm's Middlesex, NJ & Jacksonville, AR	Pending	100%	.30 carbine is 100% compatible, for others refer to web page
Johnson Arms Inc. New Haven, CT	Pending	100%	.30 carbine is 100% compatible, for others refer to web page
Johnston-Tucker Arms Co. St. Louis, MO		100%	.30 carbine is 100% compatible, for others refer to web page
Millville Ordnance Co. Union, NJ		100%
National Ordnance Azusa, CA South El Monte, CA		99%	some barrels made to work with short cast slide may be a problem
NATO Atlanta, Georgia		100%
Plainfield Machine Co. Dunellen, NJ		100%	.30 carbine is 100% compatible, for others refer to web page
Rock Island Armory Inc. Geneseo, IL	Pending	100%
Rowen, Becker Company, Inc. Waterville, OH	Pending	100%
Santa Fe Pasadena, CA		no	made no carbines
Springfield Armory Inc. Geneseo, IL		100%
Steelville Manufacturing Co. Steelville, MO		100%
Tiroler Sportwaffenfabrik und Apparatenbau GmbH Kufstein, Austria		5%	Uses GI sights, barrel band, mag catch, safety
Tri-State Tool & Die Frostburg, Maryland Roxbury, Pennsylvania		unk	No examples found so far
Universal Firearms Corp. Hialeah, FL			s/n below 95k are 95-100% compatible s/n above 95k refer to web page calibers other than .30 carbine refer web page
William's Gun Sight Co. Davison, MI		95%	rear sight dovetail eliminated on some

A Special Note Regarding Surplus U.S. GI Parts

U.S. Ordnance redesigned a number of parts, several more than once. Most of these changes were to improve reliability and/or function, manufacture time, and/or cost. A few of these changes were important enough to merit replacing the earlier part with the later variant when the carbine could be inspected by U.S. Ordnance personnel. None of these changes were so critical as to merit a massive recall.

One of the unique things about the U.S. GI M1 Carbine is almost all of the parts are backwards and forwards compatible regardless of whatever change was made. The few exceptions aren't realistically an issue when buying replacement parts. The earlier parts tend to be less common and more expensive. The later parts generally tend to be more common and less expensive. A few of the later parts manufactured after WWII are still available in new unissued condition.

Later variants that improve function, reliability, and accuracy include the following:

Barrel Band with bayonet lug, as opposed to bands without the bayonet lug (accuracy)
1st style Barrel Band	2nd style Barrel Band	3rd style Barrel Band with bayonet lug

Slides with angled face above chamber (deflects spent casings away from chamber)
Slide w/ flat face	Slide w/ angled face

Magazine Catch with the letter M on it's face, or an M2 mag catch (works with both 15 and 30 round magazines-the M has nothing to do with the mfg)
15 round mag catch	15 & 30 round mag catch	M2 15 & 30 round mag catch	M2 mag catch arm

Rotary Safety as opposed to push safety (eliminates pushing the wrong button)
Push Safety	Rotary Safety

Adjustable Rear Sight, adjusts for windage and elevation (accuracy)
Flip Sight	Adjustable Rear Sight

Note: GI Round bolts are no better or worse than GI flat bolts on a semi-automatic carbine

Some of these variations are shown on the page devoted to carbine Nomenclature. A basic introduction to the markings found on various surplus GI parts is included on the bottom of the Nomenclature page.