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Posted: 12/19/2001 5:30:29 PM EDT
Anybody have a link or can describe it? I am curious. How do they "pull" the next round in? how does the link get "de-linked"? etc
Link Posted: 12/19/2001 6:03:53 PM EDT
[Last Edit: 12/19/2001 5:57:07 PM EDT by No_Expert]
well, the linking belt part is easy. originally the rounds were on loops attached to an actual belt of material, and it stayed solid coming out the other side of the weapon. "disintegrating" links are a link that normally has 2 bands on one side, and a single band on the other, a round goes in the three loops and holds two links together, and on and on, when the round is fired, the casing is pulled from the bands on the links and they fall apart. bad picture here;

O|
.|O
O| now think of two links side by side with a round of ammo going in like a hinge pin through the three bands.

as for the feeding, it's kind of like the extraction process on a AR, the bolt pulls back, extracts the case, and when the bolt moves forward it strips a new round. except, when it extracts, it also pulls the belt over, and the bolt going forward strips a round off and into the chanmer.

hope that helps,

No_Expert
Link Posted: 12/19/2001 6:11:12 PM EDT
Ok, now what about the original .30 caliber Browning machine gun the uses the cloth belt. Does it push the round through the belt or does it pull it out, and then pushes into the chamber?

Vulcan94
Link Posted: 12/19/2001 6:16:59 PM EDT
Link Posted: 12/19/2001 6:17:44 PM EDT

Originally Posted By Vulcan94:
Ok, now what about the original .30 caliber Browning machine gun the uses the cloth belt. Does it push the round through the belt or does it pull it out, and then pushes into the chamber?

Vulcan94



not entirely sure on that one.... sorry.

No_Expert
Link Posted: 12/19/2001 6:27:57 PM EDT
The mechanism of the M1919A4 Browning is that of the original M1917 Browning, it operates by short recoil of the barrel, barrel extension and bolt locked together.

After 8mm of movement the bolt is unlocked by cams in the receiver and is then accelerated to the rear while the barrel and extension move back into battery. During the rearward movement of the bolt a fresh round is extracted from the belt and fed into the T-slot in the bolt face, displacing the empty case just extracted and ejecting in downwards.

On the return movement of the bolt the new cartridge is aligned and fed into the breech and the bolt is once more locked into the barrel extension.
Link Posted: 12/20/2001 5:26:36 AM EDT

Originally Posted By libertyof76:
Anybody have a link or can describe it? I am curious. How do they "pull" the next round in? how does the link get "de-linked"? etc



Here's some of my 1919 linked ammo, as you can see it has to be pulled from the links, same with the cloth belts. The disintegrating links were developed for aircraft use. They de-link as the bullet is pulled.


Link Posted: 12/20/2001 6:47:52 AM EDT
The 1917, and 1919 Browings pull the cartridge from the rear of the belt, then it slides down a "T" slot in the face of the breechbolt..

Basic cycle consists of pulling back the charging handle.. This draws the bolt back, compresses the operating spring, cocks the weapon, while a set of feed pawls are cammed by a milled slot in the top of the bolt. (These move back and forth in operation, to draw the belt in..) The belt is stopped by a cartridge stop, and the round is picked up when the bolt is released. Now, unless you LAID the belt in the open feedway, it will be necessacary to again draw the charging handle back, to pick up the round.. It is drawn out by a claw like extractor.. When the bolt reaches it's full rearward travel, the round is fed into the "T" slot, and slides down into alignment with the chamber, and the bolt travels home to close.

Now Brownings fire from a CLOSED BOLT. The firing pin is cocked, and when you pull the trigger, it fires, and this cycle continues..

A better description is found in a probably out of print book, "Automatic Weapons" by Johnson, and Haven..

Meplat-
Link Posted: 12/20/2001 4:03:55 PM EDT

Originally Posted By libertyof76:
Anybody have a link or can describe it? I am curious. How do they "pull" the next round in? how does the link get "de-linked"? etc



I asssume this is a general question and not specifically about belt-fed AR's, which I know nothing about.

There are different types of belts. Disintegrating belts are used in all modern U.S. weapons I'm aware of. They break into pieces after the rounds come out, and are typical of our throw-away society. Cheapskate Eastern Block nations tended to favor non-disintegrating belts, which inconvenently drag on the ground on the "fired" side but are more likely to be re-used in the field.

Perhaps a more important division (as far as gun design is concerned) is between pull-out belts and push-through belts. Browning .50 and M1919 .30 types, and probably all the old designs for cloth belts, use the pull-out style. The Browning .50 has a pivoting arm on the bolt that snaps over the rim of the round in the belt, then pulls it out and slides it downward into line with the chamber as the bolt moves back. Most more modern designs, like the M60, M85 and M249, use push-through links. Such links are split on the side that faces toward the bolt, so a lug can pass through and simply ram the round forward into the chamber.

The Mk. 19 grenade machine gun fires it's rounds without removing them from the links at all, though the links do disconnect from each other in the process, which resembles a pull-out arrangement. This is possible because about a half inch of the cartridge case is still sticking out of the chamber when the round fires.

As far as belt feeding goes, typically there is a "belt feed pawl" that is cammed back and forth by the movement of the bolt. This pushes the rounds forward (sideways) one at a time. While the belt feed pawl is doing its return stroke, the belt is prevented from going back with it by a "belt holding pawl" which pivots from a fixed point. On the Browning .50, the feed pawl is in a cross-slide in the top cover and is operated by a lever that engages diagonal tracks in the top of the bolt. The holding pawl pops up from the underside of the feedway.

The M60 and several other designs attempt to smooth out the belt feeding process by doing half on the back-stroke of the bolt and half on the forward stroke. They have two sets of feed pawls with alternating action, and a holding pawl is not needed.

Some machineguns use a rotary wheel, actuated by some type of ratchet linked to the bolt, to feed the belt. The only one I can think of is a Soviet design.
Link Posted: 12/21/2001 12:51:05 AM EDT
Thanks for the descriptions so far.
But as I am more a visual person, is there any diagrams on the operation of beltfeds, how they cycle etc? Or even just some pictures of the parts of them, say a Browning .50 or .30 cal, or a M60, cause that would help a lot!
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