ACR Forum banner
1 - 2 of 2 Posts

· Registered
83 Posts
Discussion Starter · #1 · (Edited)
So i found this bit of information that i thought was quite interesting regarding extractor springs on AAC's website. I was always told the the black insert and gold extra power spring with 'O' ring combo was the best and to try to upgrade from the blue insert and silver spring, but it looks like i could be mis-informed.

We have 5.56mm test data for the Bushmaster ‘4 coil’ extractor spring with a blue insert and an o-ring. Four uppers
completed a 12,000 round test with no extractor spring related failures. Two uppers completed an 18,000 round test
with no extractor spring related failures.
We do not recommend using extra-power extractor springs because they are under higher stress and will likely
break sooner. The included o-ring adds the desired extra extractor force without requiring a spring which would
have more force and hence more stress. Also, extra-power springs, when combined with an o-ring, may make the
extractor harder to snap over the case rim and may lead to function problems. If you do use such a spring, please
don’t use an o-ring and change the spring every 1500 rounds for mission-critical use.
Note that, again per our spring discussion, Chrome Silicon springs do not resist taking a set better than ASTM A228
certified music wire when used at temperatures below 250 degrees F.

· Mod Squad
1,906 Posts
I have seen the blue o ring before and throught it would be a good upgrade. I have fired some beat to he'll m16 and m4 types and never have I had a failure to extract due to the spring but from carbon building up I. The extractor lip. What I did have a severe issue recently was the ejector being stuck from so much carbon buildup. Which shouldn't be an issue with our system. Still a litle extra power for extraction is a plus for rapid fire engagement. Plus I believe that blue o ring is silicon versus the rubber ones normally in the extractor. I've den those crush a bit over time. But these are weapons that have has hundreds of thousands of rounds through them. Thanks for the post. I actually havnt considerd that upgrade.
1 - 2 of 2 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.