Aero Precision M4E1 Lower and BAD Ambi 45 Short Throw Safety Selector

[n517rv]

I'm working on finishing up a build and ran into an issue with the Aero Precision M4E1 Lower and BAD Ambi 45 Short Throw Safety Selector not playing nice together. Tried searching the forums, but couldn't find anything specific.

See the attached picture. The Aero Precision M4E1 lower is a bit thicker on the right side and is preventing the BAD Safety Selector from lining up properly. There is a pin in the BAD that's preventing it from lining up right.

50875

Anyone else encountered this issue? What's the best way to resolve it? I'm trying to figure out if that pin is truly necessary. Maybe just file it down and move on?

[HeruMew]

It's the "lawyer pin", most people shave them down.

It's so the companies, supposedly, can't be sued if some fudd uses it in a gun marked for 90 degree safeties and shoots themselves because the positions don't match up with the 45 degree throw.

Mill it off, dremel it, sand it. You don't need it.

However, if you plan on submitting for warranty repair or anything like that, I believe it does void the warranty.

In case you're wondering, yes, most lowers with the markings set for a 45 degree throw have the pin channel already milled open to hold those levers without modification.

[NoveskeFan]

Isn't the lower milled to accept a short throw selector? Are you inserting it correctly? Edit: Try installing it with the pin kept on the relief cut side.

[officerX]

Looks like you're installing it backwards. Have the pin on the bolt catch side of the lower. (I think)

[JSantoro]

Moved to AR Technical, as befitting the topic.

There’s a stickied post in Custom Build that describes what belongs in Custom Build.

[n517rv]

Yes, ironically this lower is "designed" for a short throw selector. It has a small keyway notched out to allow the lawyer pin to pass through... Damn lawyers!

So I actually tried installing it the other way. That's how I originally installed it, but it didn't pass a function check as the selector isn't designed to be flipped that way. The function check failed to disengage the safety.

Sounds like it's time to get out the Dremel tool!

Thanks for the replies.




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[HeruMew]

Looks like you're installing it backwards. Have the pin on the bolt catch side of the lower. (I think)

Never even noticed that in my quick glance.

It looks like it is the Ambi, so just flip it around and you're good to go.

[NoveskeFan]

Yes, ironically this lower is "designed" for a short throw selector. It has a small keyway notched out to allow the lawyer pin to pass through... Damn lawyers!

So I actually tried installing it the other way. That's how I originally installed it, but it didn't pass a function check as the selector isn't designed to be flipped that way. The function check failed to disengage the safety.

Sounds like it's time to get out the Dremel tool!

Thanks for the replies.

Sent from my SM-G930P using Tapatalk

Not sure I'm understanding. The levers can be removed from both sides of the selector barrel. Sounds like a strange malfunction.

[n517rv]

I called BAD and they were very helpful. I eventually spoke with George, one of the techs, and he suggested it was the combination of the AP M4E1, the BAD, and the Geissele SSA-E trigger. He said that the rear shelf (don't know the exact technical term) of the SSA-E is slightly taller than a mil-spec trigger.

He suggested taking a wet stone and remove a very slight amount of metal in order to fit the BAD selector. I plan to try that next after checking the operation with a mil-spec trigger.



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[alx01]

I understand that you like the BAD safety selector, but I would highly recommend getting a different safety (like a standard ambi one) instead of shaving $250 trigger.

[n517rv]

I understand that you like the BAD safety selector, but I would highly recommend getting a different safety (like a standard ambi one) instead of shaving $250 trigger.BAD suggested I smooth out the rear surface of the SSA-E and remove about the thickness of a hair. I understand your point, but would that really ruin the trigger?


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[SDSwoll]

I have the same selector in an M4E1 with a BCM trigger with no issues, Geissele triggers do sometimes have clearance issues with aftermarket or non standard parts. Generally good advice to modify the least expensive part if possible, when modification becomes necessary. Mistakes happen even during simple operations.