MkII Recoil spring replacement- Inner vs. Outer.......questions.

[TactAdv]

Okay, don't think I have ever seen a directed question to this specific topic so Ill risk double-posting.

Got around to getting some NOS recoil springs (along with every other spring in the gun) as I wish to replace them all with "new" springs, for good measure if nothing else real, since my gun is from '42 and is probably fairly experienced.

I don't have any real issues or complaints other than it's 70-odd yrs of life already passed and I have no way of knowing when they were last replaced. I almost always run it in fullauto, but it does run perfectly in any setting. There are no particular issues. So, the questions......

-is there a definitive measure for free-length of both the inner & outer recoil springs to indicate "new" condition??
-along those lines, is there a "reject/replace" length published somewhere?
-Does one 'always' replace BOTH inner & outer as a full "set" of new springs, or may one or the other be replaced "as needed"??? Whatever that might mean.....

-For FP/extractor stay springs.....same questions related to "lengths" being published, etc.

-Is there any official guidance as to the need/timing of replacing all the various detent springs, etc.??

-any other "spring" advice for the gun??

TIA.
-TomH

Information

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[Peter Laidler]

Seek and ye shall find Tom!
SPRING, return, inner free length 13,4" high. 13,00" low
SPRING, return, outer - same as above
No need to replace as a pair. Only replace as required
SPRING, stay, extractor: .098" high. .088" low
SPRING, pin, firing. .906"
I think that I published a list of the spring lengths, strengths, diameters etc etc on the forum a coup0le of years ago Tom

If you can't find it, send me your email and I'll scan the EMER inspection standards page

[TactAdv]

Peter, you really make it too easy!

Thank you, Sir, that is exactly what I was interested in.

With MG's, people often times forget the critical importance of lowly springs; Was educated long ago to the value of proper spring function and in that lesson learned also that an absolutely huge amount of functioning problems can be solved by administering to the spring variable of the overall mechanical equation at play.

-TomH

[Peter Laidler]

That's dead right Tom. They also forget that in a machine gun, every individual spring operates at the rate of fire of the gun, say 10 times a second and at high temps too. Regards