Colt 6940P--Piston Parts Pics

[Tokarev]

We haven't seen much posted about this different and unique rifle. Yes, it's a piston but I say it's different and unique because Colt's approach to the parts is quite unusual. Rather than use a solid rod, Colt added a swivel joint. This joint allows the piston to "float" free of the rod. This, in theory at least, keeps the piston from adding any undue stress on the barrel when things start heating up.

Here's the assembled rifle. Note that Colt used a built-in folding front sight rather than a railed gas block. Excess gas is vented out the small bleed-off hole located on both sides of the block.


To access the piston, the small captured pin is pushed out as far as it will go. This allows the piston parts to be removed as a complete unit. Note the opposing grooves in the block. These help free the piston if it's frozen in place from carbon. Twisting the plug will cam it against these surfaces and help with removal.



The piston assembly removed from the rifle.


The piston parts disassembled.


The transfer rod is attached to the piston by means of a small internal snap ring. The two parts are easily seperated by simply pulling them apart.


The piston. Note the three small gas rings.


The ball on the end of the transfer rod that works as the joint for the piston.


This is the latest style from Colt with the solid bolt carrier.

[Airhasz]

Thanks for sharing pics, first look for a lot uf us.

[amd5007]

Thanks for doing this. I've wondered about details of the Colt Piston carbine. I've heard that the carrier and upper receivers are different as well. Perhaps you could post some more pics of the details farther back.

[eternal24k]

This is the first time the 6940P peaked my interest,
thanks for sharing.
Looking forward to some range reports

[Tokarev]

Thanks for doing this. I've wondered about details of the Colt Piston carbine. I've heard that the carrier and upper receivers are different as well. Perhaps you could post some more pics of the details farther back.

I'll see what I can do tomorrow. I'm hoping to shoot the rifle in the morning but it might not happen until Tuesday.

[El Pistolero]

Hmm, I suddenly want a 6940P with a 14.5-inch barrel. I wonder how accuracy of the 6940P compares to the 6940, with the both being free-floated and just about identical other than the piston parts.

[Tokarev]

Surprisingly, the gas plug only has one gas port and there is no provision for suppressed settings. I can only assume the gas vents in the block allow any overpressure to exit before adding excess gas to the system.

I can't seem to find anyone with an AAC 51T flash hider in stock so I can't run my suppressor on the Colt for the time being. If I can't find a 51T in a couple weeks, I'll pull one off one of my other rifles so I can see how the Colt works with a can attached.

[tog]

Reminds me of the FAL gas system. Add a gas adjustment nut and you will have a Colt FAL.
Tog

[El Pistolero]

Reminds me of the FAL gas system. Add a gas adjustment nut and you will have a Colt FAL.
Alien

Don't tease me. The FAL is one of my favorite rifles of all time and I'm a Colt fanboy. The two together, well that would be just epic but impossible.

[tog]

Don't tease me. The FAL is one of my favorite rifles of all time and I'm a Colt fanboy. The two together, well that would be just epic but impossible.

I agree. Big, big FAL fan here, though I am learning to love the m4.