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Discussion Starter #1
Sorry if this comes out as a bit of a ramble, but I have been thinking to myself about how much of a pain in the arse it is to have to clean gas parts in assault rifles, be it a gas tube as in the AR15, or a short stroke gas piston as in the AR18, or a long stroke system as in the AK47.

Now, of course there is the roller delayed locking system of the various H&K rifles, and the sliding breach block(?) delayed locking system of the FAMAS - but both of these are supposed to be expensive and over complicated from what I have heard.

Ergo I got to thinking of how you could let enough time to pass after the round is fired for the pressure to die down, before the bolt is opened, while having a simple bolt carrier and no gas parts.

Now for my idea :D I am sure there is a (or indeed several) reasons why this wouldn't work, but in my head it works rather well. :?

Take a standard SA-80 bolt carrier to work from, it being very similar to the AR18 one as far as I know.

You have (A) the bolt, (B) the bolt carrier, (C) the cam stud, (D) the fireing pin, (E) and the fireing pin retaining pin.

As you know, starting from when the shot is released, the hammer is released, which hits the free floating fireing pin, which fires the round, the gas goes up the gas block, hits the gas piston, which pushes the bolt carrier back, which manipulates the cam stud in its channel, which rotates the bolt, which unlocks the action and allows the bolt to fly backwards. On returning to the forward position, the bolt head splines fit into the barrel extension, the bolt carrier moves forwards which manipulates the cam stud, which rotates the bolt and locks the action.

And so my idea has to manipulate the cam stud as to rotate the bolt head, without the gas piston moving the bolt carrier back.

My idea takes the bolt, and reduces it down to little more than its head, while enlarging the fireing pin to form its rear section. This while the firing pin head still goes through the bolt of course, and is free to move. The bolt carrier is stretched however, allowing for the fireing pin retaining pin to be located further to the rear. Now, the cam stud with its channel which manipulates it as to rotate, is fixed to the fireing pin rather than to the bolt head. A new cam stud is added, with a hole across it, which holds the bolt head in place, its channel is cut so that the bolt head can rotate, but no longer move forwards and backwards inside the carrier. Now, both these cam studs are on the same side of the bolt carrier, say the top, in a slight recess. A new small metal pole, is fixed rigid to the cam stud on the rear of the enlarged fireing pin, with the origional style channel, the end of the pole slotting through the hole on the bolt heads cam stud so that it is free to move through it back and forth, while rotating it.

Ergo, the fireing pin now has the motion of the bolt carrier, only it is not the gas piston which causes it to move back, but by the recoil of the round, knocking the firing pin back, while the bolt remains locked. As the fireing pin flies back until it hits its retaining pin, the linked cam studs are manipulated until the fireing pin has moved far enough back for the bolt to unlock, and the bolt carrier flies back on its recoil rod assembley as normal. At the end of its travel the bolt carrier returns forwards, the bolt head still in the unlocked position, the bolt splines interlock, then the fireing pin hits its fully forwads position, turns due to the cam stud, and the bolt rotates and locks due to the pole link, with the hammer being able to hit the rear of the fireing pin again, knocking it into the primer and so fourth....

Now, the only problem I can think of which may call for refinement, is the fireing pin slam fireing the weapon on closing, it being a great deal heavier than a normal free floated pin, but I assume some sort of spring arrangement could work there.

So, what part of my gibberings wouldn't work? :D
 

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Discussion Starter #2
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23 views and no comment/criticism?

Jeez, its must work then!

*Runs off to patent office* lol
 

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Hold your horses....read about half of it and gave up lol. I'll try to figure it out tomorrow :D
 

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Discussion Starter #5
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"Am I correct in guessing that aside from being a lazy arse and not wanting to clean your rifle as much,"

Nah, thats about it really. :D
 

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The delayed blowback action of the HK weapons delays the cycling action enough to where it allows the pressure to lower inside the bore so that the cycling is not fast enough to over pressure the barrel... this also helps with fouling. Not sure if that was what you were trying to do (since i honestly didnt read the whole thing)... but there it is.

You will also notice on G3 rifles that the left side of the forearm holds the oprod and when the oprod is fully back it exposes the gas system... wich also helps reduce ALOT of the pressure and fouling in the gas system. Same goes for some of the AK variants with the holes in the gas tube... when the AK piston moves all the way rearward... it exposes the holes in the tube and the extra pressure exits the gas system through the holes.

BC
 

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Interesting. My SKS has holes in the gas tube like that. Now I actually know what they are for lol. :D
 

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Discussion Starter #8
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As far as I know all gas operated weapons with pistons have venets in the cylinder - otherwise where would the carbon go?

And the G3 doesn't have gas parts, as it is delayed blowback. Unless I am missing something?
 

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Not all of them do... but some do. Most rifles with piston driven op rod systems compensate for fouling by having really easy disassembly. For instance... the M-14. Unscrew the nut using your hands (finger tight) or the Multi tool... and stick the chamber cleaning down in there and pull it out. It is now clean (for field purposes).

BC
 
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