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Israeli Defense Forces Modifications to the M1919A4
Text and photos by Charles Brown

When Israel was recognized as a state in 1948, their armed forces were equipped with a variety of small arms left over from WWII and, ironically, many were formerly fielded by Germany. While this assortment would make the basis for a nice arms collection, it was a logistics nightmare due to ammunition and spare parts issues.

With the post-WWII super powers, former super powers, and assorted local Pooh-Bahs, each elbowing each other for hegemony in the Middle East, Israel became closely aligned with the United States. This placed them in a position to receive large quantities of surplus U.S. military equipment.

The U.S. had lots of WWII leftovers after producing vast quantities of everything including almost five million M1 rifles, six million M1 carbines and about 494,000 new production .30 caliber air cooled ground Browning M1919A4/A5/A6 types not counting the ones converted from WWI era Model of 1917 water cooled, Model of 1919 Tank Machine Guns, and assorted obsolete aircraft machine guns.

The IDF liked the U.S. made Brownings because they were reliable, came with lots of 100% interchangeable spare parts, were available in sufficient quantity along with enough ammunition to make them a standard weapon, and they were inexpensive if not free.

Post Korean War NATO, leaned on by the U.S., adopted a standard rifle and machine gun cartridge: the 7.62x51 NATO. The ever practical IDF decided to modify their Brownings to use this cartridge to simplify supply since that supply in wartime would likely come from the U.S. or its NATO allies. Most modifications were designed so that the changes were to existing components rather than make new parts.

To prevent confusion over which parts had been modified, some parts like top covers, front barrel bearings or plugs and belt feed slides were marked with a square bottomed “U” symbol resembling the Hebrew letter H, some parts like belt feed levers modified for use with an IDF designed belt feed lever pivot system were not only unmarked but retained their original U.S. markings. Modified weapons were generally marked on the left side plate just below the top plate with “7.62” and sometimes Hebrew letters. Many IDF conversions have a six digit number stamped on the right side of the top cover just above belt feed slide opening. This may be the serial number re-stamped by the IDF, however, because the right side plate is missing on parts kits, this is difficult to determine.

As far as terminal ballistics go there was not enough difference between the 7.62 M80 Ball and the .30 caliber M2 Ball cartridge to argue about. Aside from cartridge case profile the main difference is the 7.62 x51 case is 12mm or about 1/2 inch shorter and since the projectiles are just about the same this results in a round that that is about 1/2 inch shorter in overall length. Both used a Ball projectile in the 147-152 grain range and had a muzzle velocity of 2,600-2,700 fps.

Size does matter at least in the conversion of the Brownings. If John Moses Browning’s basic design has a serious flaw, it is that the weapons derived from the Model of 1917 design were not at all tolerant of variations in overall length of ammunition. Ammunition too long would not enter or jam in the feed way and ammunition too short would cause failures to extract cartridges from the feed belts.

Obviously new barrels with properly cut chambers needed to be provided and the weight of the barrel would have to be at or near the standard .30 caliber barrel. The IDF opted to forgo the expensive Stellite barrel assemblies being used by the U.S. at the time; instead they chrome plated the bore and chamber. They also decided that the scalloped barrel locking notches and pointed tip barrel lock spring that made head spacing the U. S. models and removing the M1919A6 barrel from the muzzle end fairly easy would be replaced by square cut notches and a rectangular profile locking spring tip.

While this provided a more positive lock on the headspace adjustment it also makes setting the headspace a three handed operation. The IDF may have viewed this as “soldier proofing” to discourage the operators from head spacing experiments.

The shorter 7.62 cartridge also required modifications to the feed system comprising the casing and top cover assembly because of cartridge length and also the gas assisted recoil booster system. While the new cartridge was only slightly less powerful than the original, the IDF likely wanted to maintain a higher margin of reliability by slightly increasing the gas assisted boost energy. This was accomplished by making the orifice smaller.

The IDF modified both one piece and two piece front barrel bearings, commonly called “boosters” and “booster plugs” made from standard USGI parts. The standard .30 caliber .718 orifice was drilled out and a sleeve with an inside diameter of 13.5 mm (.532 inches) pressed into place. Occasionally one finds a modified front barrel bearing with a 15mm orifice. These are thought to be for M1919A4s modified to use 7.92x57 ammunition of which the IDF supposedly had a few.

The feed way received front and rear spacers, a new rear cartridge stop, and a wider belt feed pawl. The feed way spacers were an ingenious design that were held in place by the existing cuts in the belt holding pawl bracket and pin on the left side of the weapon. The front spacer had a hole on the right end that slipped over the original front cartridge stop and the rear spacer required changing out the original rear cartridge stop with its “U” shaped cut out for a simple “L” shaped stop.

Occasionally one will find that the rear cartridge spacer has been tack welded to the left side plate. The Ordnance Department shied away from welding on small arms but the IDF resorted to welding to tighten loose top cover latch handles and attach a small guard to the right front of the rear sight base along with other minor repairs or reinforcement thought necessary.

The new belt holding pawl required a wider cut in the left side plate, belt holding pawl bracket and the trunnion block. From samples viewed it appears that this cut was made while the casing was assembled.

The top cover and its feed system components also got a makeover to accommodate the NATO cartridge. The finger on the belt feed pawl, which prevents double feeding if a cartridge is not extracted from the feed belt, got a dog leg bend that positioned the cartridge contact surface farther to the rear to insure that the pawl was lifted high enough to prevent double feeding. This required that a portion of the belt feed slide be milled off along with a cut on the adjacent surface of the top cover.

The 7.62x51 NATO cartridges besides being shorter than the M2 Ball has a much different “rim” and extractor groove profile that in some cases due to “stacking tolerances” required modification to the original M1919A4 bolt face T slot to improve chambering reliability.

These changes are minor and not readily distinguishable so the IDF stamped 7.62 on the top of the bolts to prevent confusion with standard USGI .30 caliber bolts that had not been gauged. The 7.62 marked bolts will function with U.S. .30 caliber and 7.92x57 cartridges.

The front sight of the M1919A4 had sufficient adjustment to accommodate the NATO cartridge, but the rear sight was re-graduated to 1,800 meters maximum range and adjusted for the difference in exterior ballistics. The left side of the scale had the “MILS” designation ground off and remarked in what appears to be the Hebrew equivalent. The IDF also welded a small piece of steel to the right front of the sight base apparently to protect the slide elevation adjustment knob when the sight was folded down.

Originally, the timing adjustment on the M1919A4 was accomplished by bending the trigger slightly up or down by trial and error using timing go-no go gauge to insure that the weapon would not fire before bolt lock up because the firing pin is released slightly before the bolt is in battery. The IDF modified the spacer on some lock frames to accept a screw that bore against the top of the trigger in the manner similar to the .50 caliber Brownings to adjust timing without bending the trigger.

Apparently the IDF liked the bolt latch feature, which was on all the air cooled .30 Browning ground guns all the way back to the Model of 1919 Tank Machine Gun until about June 1943 when the U.S. dropped this feature on guns in production. About 65% of WWII production M1919A4’s were equipped with bolt latches that were designed to prevent “cook offs” in what was now an air cooled weapon but was originally a water cooled design and fired from a closed bolt.

There is some evidence that that the IDF may have reinstalled these latches in cases where they had been removed during overhauls or installed them on weapons not originally so equipped. We say this because nearly every “parts kit” sold includes a bolt latch and many of these kits have an 3/8 inch “extra” hole in the left side plate that is opposite the location of the bolt latch rivet hole in the right side plate. Additionally, there is a very wide variety in the rolled end of the latches.

The IDF also liked the concept of the M1919A6’s shoulder stock, carry handle and bipod. Apparently they didn’t like the logistics of different barrel jackets, barrels, booster caps/flash hiders and all the bipod parts. They decided to go old school and use the original U.S. concept of a kit of parts to convert any A4 into an A6.

The shoulder stock assembly remained the same, but the bipod was redesigned and improved. Instead of mounting on the front barrel bearing the new bipod mounted to the barrel jacket using a spring loaded pin that mated with the jacket holes. The bipod could be slipped on over the front barrel bearing and by pulling the pin the bipod could be slid up and down the jacket eliminating the need for the adjustable legs.

The new bipod featured a swivel mount that allowed the muzzle to be trained about 20 degrees left and right without skidding or repositioning the feet and the ring/race mounting on the jacket let the gun be canted in either direction to allow for uneven ground under the feet.

The IDF had plenty of M2 tripods but the utility of being able to remove a M1919A4 from a vehicle and slip the bipod over the muzzle and the shoulder stock on the pistol grip must have had some appeal. Many IDF guns show multiple jacket screw holes indicating that it is likely that the barrel jackets had been removed and trimmed on the trunnion end and reinstalled to allow one row of jacket holes be positioned on the bottom to give uniform bipod mounting from gun to gun.

The IDF version of the carry handle was a completely new design. The late style U.S. handle had a walnut grip with steel end caps mounted with a screw in the center of the grip and clamped to the barrel jacket with a bolt and nut arrangement that required tools to adjust the carry handle position. The IDF version featured a molded plastic handle and the barrel clamp adjustment was by means of a large wing bolt eliminating the need for tools to adjust handle position on the jacket.

The IDF used fabric belts in 225 and 230 round capacity purported to have been made by the Dutch as late as 1976. The 225/230 round belts were a better fit in the M19A1 steel ammunition box, which replaced the M1 and M1A1 boxes, than 250 round belts. They also designed a link similar to the U.S. M1 .30 caliber link for the 7.62x51 cartridge. The IDF link lacked the flared skirt at the rear of the forward loop and was properly dimensioned for the NATO round.

The entire series of Browning’s .30 caliber machine guns were designed to use fabric belts and as metallic linked ammunition became more prevalent several problems arose; one being excessive wear evidenced by grooves and chipping to the floor of the feed way. The U.S. solved the wear problem by chrome plating this area on new built guns and to reclaim worn trunnions on weapons being rebuilt.

For the weapons being rebuilt, this process involved removing the trunnion and reinstalling it after chrome plating. The IDF opted for milling the trunnion and installing a plate attached with screws apparently without removing the trunnion from the casing.

Many IDF guns have had the pintle bolt hole in the mount adaptors, side plates and trunnion bored oversize and some sleeved back to original size to reclaim worn casing assemblies. Some believe this to be a purely IDF modification, however, Ordnance Department rebuild requirements dating from 1970 mention this same technique.

The day of the M1919A4 may be over in Israel but it soldiers on in other countries. A few have turned up in Iraq and Afghanistan and minus the right side plate right back in the U.S. as candidates for semi-auto conversions to shadows of their former selves.

In 2009, the AP published a photo of a student demonstration in Portugal and mounted on what appeared to be an armored personnel carrier was one of John Moses Browning’s finest. Not too shabby for a weapon last produced at the Rock Island Arsenal in 1955 from a design that dates back to 1919.

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