Suppressor causing my AR to fire bursts and fail to reset

[Dennis]

Which SD trigger are you running? SD-3G, SD-E, SD-C? The 3G is touchy by design and I ended up selling mine off. I have several SD-Cs and SD-Es with no issues to include in 9mm and .22 builds.

Good Luck!

Dennis.



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[Disciple]

Yea I've been doing some googling and it seems like lots of people with Geissele triggers are having this issue. Seems like hammer follow is the issue. Seriously thinking about just ditching the Geissele trigger and going back to the milspec one. This is just ridiculous.

Consider the LaRue MBT-2S. It has a rather long reset but a very nice break. I have not read of any problems with it other than one member here who found it would not fit the trigger pocket of his receiver. He did not appreciate the dismissive response he got from Mark LaRue but I don't believe he measured the trigger either.

[georgeib]

Are you, by chance, using anti-rotation pins in your FCG?

[polydeuces]

'Good' to see this happened to someone else as well.

Zeroing my new 13.5 .308 upper with a 10" F1 can, Geissele SSA trigger, VLTOR A5 (for ar10), everything else stock.
10 round mag loaded with 5 rounds Federal Sierra 168 bthp. Geissele SSA trigger.

Broke the shot and HOLY CRAP WTF was that???!!! Took me a few seconds to comprehend what happened - I just experienced a full auto burst.
Still haven't figured out how that happened and have not used that particular can on that upper again.
Has not repeated with my other can (F1 w different internal design.
Be happy to hear some ideas.

[Todd.K]

Bump fire.

[okie]

Are you, by chance, using anti-rotation pins in your FCG?

Nope.

[okie]

Bump fire.

I considered that, but it doesn't explain why it didn't do it for the first like 500 rounds, and why it got progressively worse over time.

Oh, and the cyclic rate is way high. Much higher than I think an accidental bump fire is capable of. It also doesn't have that variable cyclic rate that bump fire does. It's just zip and it's gone.

[okie]

'Good' to see this happened to someone else as well.

Zeroing my new 13.5 .308 upper with a 10" F1 can, Geissele SSA trigger, VLTOR A5 (for ar10), everything else stock.
10 round mag loaded with 5 rounds Federal Sierra 168 bthp. Geissele SSA trigger.

Broke the shot and HOLY CRAP WTF was that???!!! Took me a few seconds to comprehend what happened - I just experienced a full auto burst.
Still haven't figured out how that happened and have not used that particular can on that upper again.
Has not repeated with my other can (F1 w different internal design.
Be happy to hear some ideas.

Yea it seems to be pretty common if you do some googling. I tried multiple suppressors and they all do it.

[georgeib]

Yea it seems to be pretty common if you do some googling. I tried multiple suppressors and they all do it.

It sounds like the disconnector spring is getting weak, and the suppressors might be increasing the carrier velocity enough to make it overrun the weak spring. Maybe.

[okie]

It sounds like the disconnector spring is getting weak, and the suppressors might be increasing the carrier velocity enough to make it overrun the weak spring. Maybe.

That's what others have suggested, and sounds pretty reasonable. Problem is, the trigger only has like maybe 1500 rounds on it tops. Proly closer to 1000. Only thing I can figure is the 22 conversion I was using killed it. But I checked, and the manufacturer doesn't warn against them. Or 9mm for that matter, which is way more severe even.