Double "Rat's Tail Springs"

[Peter Laidler]

Interesting........ and this very subject has been aired here before. Mechanically, multiple spring should be would and used opposing. This prevents the inner spring coil binding the outer (which is supported externally by the return spring tube of course). It's the ROD, return spring by the way!

I have just looked at 4 sets of springs. In a Bren, the outers (C1-BE6897) are all the same (except for a very minor change on the very earliest Mk1 guns) as are the inners (C1/BE6896). All of the outers are wound the same way and 3 of the inners are wound in the opposite direction. The 4th inner being would the same way as the outer. And operates perfectly!

What is very interesting is that nowhere in the technical information, the EMER's, parts lists, technical spec, Inspection standards etc etc does it specify that the inner spring should rotate opposite to the conventional outer spring. Indeed, several years ago I published an Armourers crib-sheet for the identification of the many Bren springs...., some VERY similar but soooooo different in application. I think that in this case, it doesn't matter as coil binding will not(?) be a problem. In the Sterling SMG the tech spec distinctly states that Armourers will find return springs wound in either direction.

And what about the L1A1 rifle double return springs.............. I think that this will run and run awhile

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[Vincent]

I think the diameters of the springs and the distance between coils is what keeps them from binding. Same with the FN49’s triple return spring setup.

In the Sterling SMG the tech spec distinctly states that Armourers will find return springs wound in either direction.

That’s interesting, Peter. It never crossed my mind to look for that.