New SA42 Main Springs

[fjruple]

Folks this is not another scam for springs.

I have approached the Wolff Gunspring company to see if they would be able to do a short production run of new Main Springs for our SA42s. I need the following information from the SA42 owners for the Wolff Gunspring Company:

...if you supplied us with the OD, wire size or spring ID, the number of coils and the overall length of the existing spring.

I don't need the specification for the full length version just the modified "cut down" version.

I am not taking any money or orders until I can see if this is doable.

Please let me know if you are shooting a 8mm or 7.62mm NATO version of the SA42 as there may be a difference in Main spring length.

I like a lot of folks have only one last weakness in our SA42, the shorten main spring. This is going to be a one-time shot and it still may not work out. I believe it to be worth the try.

--fjruple

[sdk1968]

i'll measure my spring and count the coils so you can compare to some other people...

im on a WLA receiver and left all that i could in it.

[salt6]

Best thing to do is the full size spring. Then the builder can cut to size. Also people with full auto 42's would be able to use them. This would increase the customer base.


salt

[PvtJoker]

Best thing to do is the full size spring. Then the builder can cut to size. Also people with full auto 42's would be able to use them. This would increase the customer base.


salt

Not trying to be a smart-ass here Salt6, but what would be the point in making custom springs that replicate what we already have? Why not just buy an original, if you have to cut it down anyway?

[JBaum]

I don't see one very important part of the spring specifications here.... strength. The reason the springs are weaker than they should be is because they're cut off so they'll fit with the semi bolt. Cut off 10% off the spring, and you lose 10% of the power the spring needs to push the feed lever and bolt forward. A weak spring is the problem here, not the number of coils the spring has.

Get full-length power in a spring that's short enough to be compressed inside the receiver when using a semi-auto bolt, and you'll have the spring problem solved. Specs should include OD, ID, minimum length, and strength. The number of coils possible is determined by the compressed length and wire diameter. If it has to have a certain minimum length, that will determine the number of coils, because only a certain number of coils will fit. The OD and ID will be the same as the standard MG42 recoil spring, since that's what everyone is using. The uncontrolled variable is the length of the semi-auto bolt extension, which determines the minimum length of the recoil spring when compressed.

Getting a spring that is as strong as needed, then having to cut off a coil or two to get it to fit, defeats the purpose. Get the spring to fit and make it strong enough (as strong as a full-length spring) without having to cut anything off, and the problem is solved.

[tomcatshaas]

I'm not sure the cut down spring is a problem. I have not had any problems with the cut down spring, so I am not seeing the issue. Maybe I am just lucky, who knows. With the ample supply of new full springs out there, maybe start out with a new spring and when it starts to give problems replace it. Just my $6. worth of input.

How many are really having issues with the cut down springs?

TC

[salt6]

Best thing to do is the full size spring. Then the builder can cut to size. Also people with full auto 42's would be able to use them. This would increase the customer base.


salt

Not trying to be a smart-ass here Salt6, but what would be the point in making custom springs that replicate what we already have? Why not just buy an original, if you have to cut it down anyway?

Yeah OK, I stand corrected . I think jbaum has the right idea.

[fjruple]

To All--

Thanks for your comments and thoughts on the subject. I believe the last reliabity issue with the SA42 is the main spring. I have found that when I use new belts the tightness of the link to cartridge causes the action to slow down which I would think the cut down main spring is performing only marginally. I think jbaum hit the nail on the head about compressive force. What I will probably do is visit Wolff Gunspring and take two springs, full size one and a cut down one to ball park the compression part of the equation. I will probably still need some of the main spring data to get an idea of the variations in SA42 out there. Please let also me know what caliber you are shooting in your SA42 8mm or 7.62mm. PM the info to me at this forum.

I am out of town on business until the end of the month and probably not going to be able to get to Wolff until May sometime. Again this whole thing can go no where but I am willing to give it a try.

--fjruple