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Chester Nimitz
April 24, 2017, 07:01
Here are two versions of the Recoil Tube Nut: The first two to the left have a stepped shoulder to seat the spring, the third (right) does not. Both have been observed with Lithgow Parts kits. All the standard book diagrams show the one with the stepped shoulder. When was the shoulder done away with?

http://i28.photobucket.com/albums/c216/AmericanIdols1944/IMG_2233_zpsfbwltzoo.jpg (http://s28.photobucket.com/user/AmericanIdols1944/media/IMG_2233_zpsfbwltzoo.jpg.html)

Here are two versions of the Recoil Spring Plunger: The one on the left has a hollow tube shaft, the right is a solid bar shaft. Sorry for the poor contrast. Any ideas when these changes took effect?


http://i28.photobucket.com/albums/c216/AmericanIdols1944/IMG_2232_zpslg3af0pu.jpg (http://s28.photobucket.com/user/AmericanIdols1944/media/IMG_2232_zpslg3af0pu.jpg.html)

gunplumber
April 24, 2017, 08:14
The short one is is the original. It fit only the wood stock. Center hole was not threaded internally (wood stock didn't need it).

Screw and neoprene washer added to keep water out. Needed to thread nut for screw. I do not know if they were only replaced with new threaded ones, or if existing ones were threaded at the local level.

Discovered that hydraulic pressure would rupture stocks if fired wet. Little sealing screw and washer discontinued. Hole drilled near end of return spring tube for drainage.

UK goes to plastic stock, needs internal threaded for buttplate screw. Also, little flange added to keep spring centered.

So there are

short no thread
short thread w/screw
short thread screw discontinued
long thread.

Chester Nimitz
April 24, 2017, 10:13
Thank you. I hear you on the concern of the sealing screw and the hydraulic pressure problem. Then the British Rifles fitted with Marynyl stocks by default are subject to the same hazard potential, since those required a longer screw threaded into the same hole?

Likewise, are the flanged Recoil Spring Screws only found in UK rifles?

gunplumber
April 24, 2017, 12:16
I think what you are seeing as flanged is just a seized washer. Never seen one where the nut had an integral flange.

And yes, that's why there is a drainage hole in return spring tube.

But it is not in all of them. I'll have to check the REME I&R standard to find out when this started, and whether it applied to the plastic as well. And whether it was just a new production change or to be retroactively applied to guns in service.

y18376
April 24, 2017, 20:14
But it is not in all of them. I'll have to check the REME I&R standard to find out when this started, and whether it applied to the plastic as well. And whether it was just a new production change or to be retroactively applied to guns in service.[/QUOTE]

It applied to Aramid nylon furniture also. :]

Chester Nimitz
April 25, 2017, 15:43
Thank you for checking.

What is bugging me about the Recoil Tube Nuts with the flange to seat the spring is that it appears in the isometric drawings published in Skennerton's books dedicated to the Lithgow L1A1's. Whereas, my earliest Lithgow 1964 matching parts kit has the short Recoil Tube Nut, without spring flange.

And I am starting to suspect the majority of flanged Recoil Tube Nuts on the market today (with dark blued finish) were taken from Metric FALs, thus being one of several parts that is interchangeable with the Inch pattern guns