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Getting Started


This paragraph is to provide a quick check list of those parts which are unique to the C1/C5A1 and those parts that can modified. In later chapters of this writing I will get into detailed discussion of the modifications and parts.

I will say that I had no problem obtaining the required C1/C5A1 parts after having been able to identify what I needed. These parts are expensive!! So if you are looking to do this project cheaply with minimum machining skills that’s just not going to happen. You will find individuals who can sell you “complete” conversion kits but the kits are lacking several parts simply because the seller is unaware of all the required parts for conversion to the C1 and then to the final C5A1. As with any seller, there are individuals who want a quick profit and have done their own conversion to the Breech Bolt Assemblies and selling them as original when in fact they are not to C1 specification and are dangerous to the shooter. I was able to find all of the original parts most in new condition for the conversion except for the barrel which I could not import and the rear guide NSN# 1005-21-864-5268.
The rear guide I had to personally manufacture from scratch. In conversation with my Canadian military source he indicated that this part was installed during the C1 remanufacturing process and very, very rarely broke off or wore out. He could not remember ever having to replace the rear guide or ordering a replacement. And sadly all the rear guides were destroyed that were attached to the C5A1 when they were destroyed.

Breech Bolt Group:

Breech Bolt – NSN# 1005-21-850-4068 Can be modified from original M1919A4 or Israeli 7.62mm bolt assemblies. Israeli breech bolts are probably easier as the T-slot has already been modified to the 7.62mm NATO cartridge.

Extractor Assembly - NSN# 1005-21-848-9145 Can be modified from original M1919A4 Extractor.

Unique parts—
Ball bearings - two NSN# 3110-00-100-6162 Can be purchased
Compression spring – two NSN# 5360-21-848-9117 Can be purchased
Spring Seat Pin – two – NSN# 1005-21-848-9116 Can be manufactured from rod stock
Stud (Charging handle) - NSN# 1005-21-844-3354 Can be manufactured on Lathe.

Barrel, Barrel Bearing and Barrel Jacket:

Barrel NSN# 1005-21-848-9110 - Can easily be modified from new Israeli 7.62mm NATO barrels. Very difficult if not impossible to import original barrels into the US with proper license. Originals were remanufactured .30-06 barrels. I will provide details in a later installment on how the Canadians converted these barrels.

Front Barrel Bearing Assembly NSN# 1005-21-848-9118 - This assembly is the original one piece M1919A4 front barrel bearing with a 7.62mm NATO bushing pressed in. This conversion is not unlike the Israeli conversion.

Front Barrel Bearing Assembly NSN# 1005-21-113-1421 - This assembly is the original multi piece M1919A4 front barrel bearing with a 7.62mm NATO bushing fitted. The unique aspect that can identify an original is that unlike the Israeli conversion the front plug is permanently pinned in with three pins through the Barrel Bushing Lock Band.

Machine Screw NSN# 5305-00-984-7360 This screw is used to hold the barrel jacket to trunnion block. For those of you who really want to get down in the weeds on this conversion. This screw is a Phillips Head version of the single slotted screw used on the American Brownings.

Barrel Extension Group:

Barrel Extension Assembly – NSN# 1005-21-848-9122 Can be easily modified from original M1919A4 Barrel Extension.

Cover Group:

Gun Cover Assembly NSN# 1005-21-848-9123 Originally remanufactured from M1919A4 top covers in C1 remanufacturing process. Requires detailed machining of top cover and addition and welding of a new bridge and plate cover for a unique C1/C5A1 Slide and Pawl Assembly NSN# 1005-21-848-9676. The Slide and Pawl Assembly has many unique parts to the C1/C5A1. I will cover in detailed section on Cover Assembly.

Belt Feed Slide Lever NSN# 1005-21-854-2806 - Unique to C1 remanufacture process can be identified by a 1/8 inch size number “2” being either stamped or etched into the lever ¾ of inch from the hole for the Belt Feed Lever Pivot Pin NSN# 5315-00-515-7434.

Casing Group (Left Side):

Trunnion Block Assembly – Modified from Original M1919A4 during C1 remanufacturing process. Cut performed on left side of block for new unique feedway bracket assembly, and belt holding pawl. A new hole for the belt holding pawl spring is drilled. Additionally, a space is machined on the top of the trunnion block for clearance of the bullet of the 7.62mm NATO cartridge.

Feedway Bracket Assembly NSN# 1005-21-878-5161 Unique to C1 remanufacture process. Consists of two parts the feedway bracket and filler piece. I have seen two types of these brackets one that has the filler piece attached to the feedway bracket and one that does not. The filler piece fills in the space on the trunnion block where the original .30 caliber belt holding pawl was located. This part can only be made in a well equipment machine shop. The feedway bracket assembly replaces the original .30 caliber feedway bracket which was riveted to the left side plate. The feedway bracket assembly is retained in place by two hexagon socket drive cap head screws 8-32 UNC-3A NSN# 5305-00-988-7602 and one hexagon socket drive cap head screw 8-32 UNC-3A NSN# 5305-00-988-7601. These screws can be purchased in any well stocked hardware store.
Belt Holding Pawl NSN# 1005-21-848-9127. Unique to C1 remanufacturing process. Probably can be manufactured in well equipped machine shop.

Front Guide Body NSN# 1005-21-848-9112 Unique to C1 remanufacturing process. Probably can be manufactured in well equipped machine shop.

Front Guide Spring NSN# 1005-21-848-9113 Unique to C1 remanufacturing process. Probably can be manufactured in well equipped machine shop.

Belt Holding Pawl Axis Pin NSN# 1005-21-848-9114 Unique to C1 remanufacturing process. Probably can be easily manufactured. Looks very similar to the axis pin used on the M37 Browning Tank Machinegun.

Rear Guide NSN# 1005-21-864-5268 Unique to C1 remanufacturing process. Can be easily manufactured in well equipped machine shop. Probably the hardest part to come by. I had to make mine. Rear Guide Pin NSN# 5315-00-844-4789 and Rear Guide Rivet NSN# 5320-00-714-7662 are used to hold the Rear Guide to the Left Side Plate.

Feed Extractor Cam NSN# 1005-21-874-8292 Unique to C5A1 upgrade from C1. Generally Feed Extractor Cams were removed and modified and reinstalled. Easy Modification.

Link Guide Platform NSN# 1005-21-848-9111 Unique to C1 remanufacturing process. Can be easily manufactured in well equipped machine shop. Probably the hardest part to manufacture. The part is stamped steel and then heat treated to hardened the part. A suitable replacement can be probably machined.

Casing Group (Right Side)

Right Side Plate is modified to take the Link Guide Platform for the M13 links to proper feed out of the action. Original M1919A4s were used in the initial C1 remanufacture process. In this case a new registered semi-automatic right side plate for a semi auto M1919A4 was used. Modifications would be the same as the C1.

Breech Bolt Retracting Bar Assembly NSN# 1005-21-854-3419 While most people believe that the retracting bar is unique to the C1/C5A1. This field modification was initially conducted on the .30 caliber M1919A4 back just before the M1919A4 was remanufactured to C1 configuration. No doubt that those .30 Caliber M1919A4 not converted in the field by the Canadian military were converted during the C1 remanufacture process. Strangely, after this field modification was made the .30 Caliber M1919A4 Browning was identified as a C1A1. Through the history of the M1919A4/C1/C5A1 I have counted no less than four maybe five different breech bolt retracting bars used in Canadian service. The oval shaped retracting bar seems to be most common one. Canadian Army EME Manual E317 Instr 4 dated 28 April 1967 details this modification.

Retracting Bar Guide NSN# 1005-21-844-3356 Two Required.

Retracting Bar Detent NSN# 1005-21-844-3357

Machine Screw NSN# 5305-00-984-7363 10/32 UNF-2A Philips Four screws are required and can be obtained in any hardware store.

Rear Sight Leaf Assembly -- NSN# 1005-21-848-9126 Unique to C1 remanufacturing process. The rear sight leaf is calibrated in meters for the 7.62mm NATO cartridge.

Well this covers most of the major parts and modifications to the M1919A4 to the C1 and then the upgrade to the C5A1. Most of the parts are modifications of existing M1919A4 parts which can be easily performed while others are unique to the C1/C5A1 and require to be obtained to make the conversion work. With a little patience and lots of money most of the parts are obtainable. To build this gun just to run the cheaper M13 7.62mm NATO links should not be the driving factor in your build. It would be far less expensive to get an Israeli kit and use the Israeli 7.62mm NATO Browning links. If you are seeking something unique then this document is a guide to go by.

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