KAC PDW (Dual tappet gas system)

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[ARCHIVED THREAD] - KAC PDW (Dual tappet gas system)

Posted: 7/14/2006 5:31:37 AM EDT

Could someone please enlighten me about the operation of this system. I have only seen a few picts of this weapon and definatly none of it field stripped.

The AL-7 and Ak-107 come to mind here and the Balanced Automatic Recoil System(BARS) BARS Animated

Thanks Mike

Posted: 7/19/2006 2:32:59 AM EDT

[#1]

ok please look again someone????????-

There may be some value to all of you piston/upper kids here??

thanks Mike

Posted: 7/19/2006 4:55:21 AM EDT

[#2]

wish i could give you a straight-up answer man, but i know about as much as you.

about two months ago (i think) someone mantioned the KAC PDW. shortly thereafter, a member "in the know" posted that the only thing he could tell anyone is that it *isn't* really anything like an AR. if there were to be any comparisons drawn, it should be with the various AK-types. and that's about where it was left...

Posted: 7/19/2006 5:51:17 AM EDT

[#3]

There was a long thread on the KAC PDW about 2 months ago. Its probably archived now. Coldblue put out some information on the system. Most of it concerned the cartridge, but I don't remember specifics of the gas system being addressed.

Posted: 7/19/2006 6:54:12 AM EDT

[#4]

Rex if you question is on the KAC system, sorry I can't help you. I have not seen diagrams of its system.

The AK system you posted looks pretty standard - except for the fact it allows some gasses to push on a forward moving piston. It looks like this 2nd piston moves forward to counteract the recoil from the bolt moving backward. A forward force canceling out the rearward force.

It's an approach similar to the idea of a recoiless rifle (which has a rearward jet pushing forward to offset the recoil from launching a projectile out the muzzle).

Posted: 7/19/2006 7:01:20 AM EDT

[#5]

very interesting................

Doesnt the mass of the forward moving bolt/piston have to be the same as the rearward moving bolt/piston?

I wonder what full auto groups look like at 100 yds?...........

Posted: 7/19/2006 7:31:11 AM EDT

[#6]

Quoted:
Doesnt the mass of the forward moving bolt/piston have to be the same as the rearward moving bolt/piston?

If they are at the same velocity - yes the mass must be the same for absolute cancellation.

Posted: 8/14/2006 9:32:39 AM EDT

[#7]

Well its been about a month anything new found out or forgotten?

Posted: 10/26/2006 2:10:17 PM EDT

[#8]

Regarding the animation, here is some information on the Russian "balanced action"

AK107/108

AEK-971

AEK971 is being developed at Kovrov Machinebuilding Plant (formerly known as Kovrov Machineguns Plant) by chief designer S.I.Koksharov.
Key feature of the AEK971 is gas driven, balanced action with rotating bolt barrel locking. Balancing mean that AEK971 gas drive has two gas chambers and two gas pistons. First gas piston is linked wia gas rod to the bolt carrier an moves as usual. Second gas piston is linked to the balancing msteel weight and moves in opposite (to main gas piston) direction. This design is implemented to eliminate 3 of 4 total impulces of the movement that affect rifle during the full-auto fire. 1st impulse rifle received when bullet moves along the barrel - this is recoil itself. Second impulse rifle received when heavy bolt carrier/bolt group moves along the receiver back and forth. Third impulse is received when bolt carrier/bolt group stops in the rear position and fourth - when this group stops in forward position after new cartridge is chambered. Synchronous and opposite movement of the balancing weight eliminates all except the recoil impulse, so rifle becomes far more stable during full-auto fire.
The gain of accuracy in full auto is whole 15-20%, when compared to AK-74 asault rifle in the same kaliber. The newly adopted by Russian army AN-94 assault rifle has slight edge over the AEK974 only in short burst (2 rounds only) mode. In full-auto medium or long bursrt fire mode (3-5 or 7-10 rounds per burst) AEK974 wins hands down, being also some 0.5kg lighter than AN-94, simplier and cheaper to manufacture.
At the present time AEK971 in both 5.45x39mm and 7.62x39mm chamberings is being tested by Russain army in some quantities (my sources said that at least one hundred of AEK971s in 7.62mm was aquired by Russian army for field testing).
AEK971 has folding metall buttsock with plastic coating (to protect shooter in extremely hot or cold conditions), plastic forearm and fire control grip, and uses standart AK-47 or AK-74 30rds magazines (depending on chamberings). It also features safety switch/fire mode selector of diferent appearance (when compared to Kalashnikow design). Fire selector allows 2 modes of fire - single shots semi-auto and full auto. At some 800-900 rounds per second it's not impossible to manually control lenght of the fire bursrts, and this weapon is more stable during the fire than ordinal design rifles, so 2 or 3 rounds mode is not implemented (at least, at this time).

Regarding the KAC system, I have read several online that (1) it used a dual-piston system, (2) the recoil spring runs the full length of the upper receiver, right up the middle between the two gas pistons and (3) the bolt system is AKM/Kalashnikov style. The KAC PDW Flyer refers to a "'controlled motion' operating group designed for low recoil", but if you look at the photos, it doesn't look like it employs a Russian-style balanced action. You can see two conventional gas regulators at the front of the monolythic upper and a conventional operating rod on the right side.

Posted: 10/26/2006 5:44:36 PM EDT

[#9]

I was hoping for a field stripped picture. SOF mag just had an article but it was not informative at all. I am very curious as to the mechanical operation of this weapon.
I did notice from the flyer pict that the pistons were side by side. I would just like to know how the system is counter balanced or what ever it likes to be called.

thanks Mike

Posted: 10/26/2006 10:40:53 PM EDT

[#10]

I don't know a lot, but from what I do know now, I think it would be a cool thing to have.

TS

Posted: 10/28/2006 4:40:56 PM EDT

[#11]

Quoted:
I don't know a lot, but from what I do know now, I think it would be a cool thing to have.

TS

+1 - The KAC PDW is closer to the assault rifle ideal than the M16 or even the M4. It's pretty darned close to what the Infantry Board asked Gene Stoner for in the late '50s. CONARC Commanding General Willard Wyman told Stoner the Infantry Board was looking for a .22 rifle with respectable hit probability out to 300 yards. The 300 yard requirement turned into 400 and then 500 yards between the Infantry Board and the Pentagon (See The Black Rifle pp 55-56). The KAC is a .243 and not a .22, but you get the picture.

Posted: 10/28/2006 4:55:51 PM EDT

[#12]

Quoted:
I was hoping for a field stripped picture. SOF mag just had an article but it was not informative at all. I am very curious as to the mechanical operation of this weapon.
I did notice from the flyer pict that the pistons were side by side. I would just like to know how the system is counter balanced or what ever it likes to be called.

thanks Mike

In the article by Gunwritr in SGN, I think he said that KAC didn't want the field stripped gun photographed, so I would imagine the inner workings of it are goin g to be a closely held secret. Maybe coldblue or gunwritr can tell us a little more, though, [hoping].

[ARCHIVED THREAD] - KAC PDW (Dual tappet gas system)

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