SuperSafety inconsistent in different lowers

TheBigJDawg

I have a SuperSafety in an Aero lower.
I have the following uppers:

Aero 16" Upper
Aero 11.5" Upper
Unknown 16" upper that I bought off of Reddit back in 2020; I have no idea the brand/make of the barrel or the stripped upper, but the handguard seems to be generic budget one.

The unknown upper's stripped upper receiver seems to be almost identical to the stripped upper portions of the two Aero uppers (they all have that "shelf"), but the SuperSafety only works in that unknown 16" upper.

In the 16" Aero upper, it ALMOST seems like it could work, but the BCG will bind up at least 50% of the time when doing a function check.
With the 11.5" Aero upper, it binds up almost all the time. In many cases, it will start to bind up before the BCG is all the way back, i.e., the extractor part of the BCG is very visible in the action.
What's strange is with all, when the SuperSafety is in "normal" mode, you can see that the lever is able to go back and forth fine when doing a function check with no issue, but when you put it in "SuperSafe" mode, it binds up pretty bad.

I have three lowers (one of them being the one with the SuperSafety with maybe one or two quarters down the buffer tube), so every one of them has a home now, but it would be nice of the SuperSafety lower could be used in the other ones.

What are my options here? Should I look to making the lower compatible with all? Or just accept that one upper works with it?

hoffmantactical

TheBigJDawg The bindings dependency on transverse cam position is most likely due to the lever shifting to one side. Probably needs a centering block.

The root issue here is the lever. Needs some material removed from the bottom of the tail, preferable curving it to match the uppers ID.

TheBigJDawg

SuperSafety inconsistent in different uppers*, not lowers. Oops

TheBigJDawg

hoffmantactical

The lower I have cannot fit the centering block that my SuperSafety came with; it's too narrow. In addition, I'm not sure what would be the "center" position based on how my lower looks here: https://imgur.com/a/narrow-lower-29Q9yu5

I've tried using an earbud plastic cover, but it didn't really work well as a centering block.

Since posting my original post, I've slapped the 11.5" onto the lower again, and now it works??? I'm not sure what changed, cause literally nothing did. Occasionally it will ALMOST bind up, maybe less than 1% of the time. The lever tends to move to the left side of the lower, as seen here: https://imgur.com/a/leaning-left-HLIsaEg

I tried putting it into the 16" Aero upper, but that still binds up. Seems that the 16" mystery upper, which has a stripped upper almost identical to the others, is the best performer here.

hoffmantactical

TheBigJDawg You have a common lower with only the right "cheek" intact. Should actually be OK without a centering block. I would definitely remove some material from the lever.

TheBigJDawg

TheBigJDawg
Replying to this, the 11.5" will have moments where it works flawlessly with the SS lower, and then it will start to bind up like crazy randomly. A good smack of the buffer tube will get to unbind though.

Not sure what is causing it, since I put the 11.5" upper on, it works fine, take it off, try again, and then it may start to bind up.

Still no issue with the unknown 16" upper, the Aero 16" upper still binds up most of the time.

TheBigJDawg

hoffmantactical
From under the tail?
I've removed some material (not much if any) from the top of it, do you have a diagram of sorts to demonstrate the area(s) I should focus on?

hoffmantactical

The underside, where it contacts the inside bottom of the upper. Make it rounded to match the uppers curve.