
Originally Posted by
rsilvers
I never felt comfortable referring to spring by the number of coils when the drawing says that the number of coils is a REF and it changes from batch to batch.
I ran spring analysis software on pretty much all extractor springs in the Brownell's catalog. The newer military gold one was not bad but still over-stressed (over 45% of MTS). There are some absolutely horrifyingly bad extractor spring designs in some of 'your' favorite bolts (I don't mean you specifically, lamarbrog). Some were at 80% of MTS.
I was not able to buy the spring that I wanted in the AAC bolt - had to have it made. Basically, the AAC spring is the original M16 spring design (which is not overstressed). Except I had them made from MountJoy brand Rocket Wire to make it even lower % of MTS, and then the extraction force was raised to carbine standards without adding additional stress to the spring by the o-ring.
I pull all other springs out of bolts, including the newer gold military ones.
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