CIA L1A1 sporter mess

[s&w 24]

took a chance on a canadiean reciever CIA sporter and let just say it's a mixed bag. when I test fired the weapon the gas system would not adjust,play with things all you want it ran wide open. found out the gas tube was missing the retaining pin. Mesured bbl (20") and looked at the gas block/front sight ass. and it's british proofed so I think OK get new brit. gas sytem parts and start from scratch. Not so. the inch parts I ordered don't fit on my rifle!
http://i239.photobucket.com/albums/ff38/radom35/100_0188.jpg
the top tube is from the rifle I own the bottom is the NOS L1A1 tube I purchased.
http://i239.photobucket.com/albums/ff38/radom35/100_0189.jpg
left is the old part right is the new won't fit part.

so what parts do I need to by and how do I get the gas system parts
installed correctly?

[FULLMETALJACKET]

The bottom tube in the first picture looks like a recoil spring tube for the lower receiver.

[bykerhd]

At least it is an L1A1 recoil spring tube.

Not sure what is going on with the gas plug. Maybe it's from the Indian version ? All the regular British, Canadian and Australian stuff interchanged.
I thought.

[s&w 24]

OK soo the guy sent the wrong part. What is the right way to install the parts I have? I know I need a tube retaining pin, what size is it? I didn't get one with the rifle.

[Radio]

Coat hanger wire is the perfect size. Custom cut to fit. Also happens to be super-cheap.

--Radio

[wolfkidd]

I'm looking at your parts there, and the one item I'm not seeing in your replacements is the gas-adjusting nut, the one part that controls the whole thing. In fact it's the one part I can think of that would cause trouble with the gas system: the gas-plug is pretty much "on/off" (for launching grenades), the gas-tube, as long as it's not binding the piston, should be fine. The retaining pin can be made with an appropriate bit of wire, or a small finishing-nail cut to size.