Charging handle trouble after ss install

Mysterymachine8

I installed the super safety and it seems to be done correctly after careful attention to detail. My trouble is regardless of the setting the ARP is in, the charging handle will not pull all the way back. Effectively making the trigger dead all the time. How can I get the charging handle to fully pull back and the ARP to function correctly (charge, cycle, reset properly, etc.)?

hoffmantactical

Lever interfering with the carrier? Removing some material from the underside of the levers tail should fix it.

Mysterymachine8

hoffmantactical I will give this a try thank you!

whoisjohngalt

What do you recommend for this interference with the rear of the recessed and un-Dremeled upper slot? (See metal showing through blue Dykem.)

Metal SS. Lever ground to match CAD model. 3D printed model interferes at same point but nylon "gives" enough that it's fully functional when installed with the same metal cam and lower/uppers.

Manufacturer of metal SS unknown.
Two different manufacturer's uppers.
300 AAC Blackout with 10.5' barrel and standard buffer (3 oz) and buffer spring..
With the metal lever, bolt carrier stops and sticks before it's racked rearward enough to catch on the bolt catch.
Bolt catch works with 3D printed nylon lever, despite marks of interference on the nylon lever.

Thanks!

whoisjohngalt

After investigating with a bit more Dykem, I don't think the two points in the corner of the lever are causing the BCG bind. Perhaps relieving those areas on the lever would make the lever bind even worse, as would relieving the aft end of the upper slot (where the perimeter of the slot has a recessed edge) as some SS manufacturers have recommended and some users have done.

As Tim suggested, the bind is between the inside BCG surface of the upper and the BCG so relieving the areas described and illustrated above in my photo might allow the lever travel further rearward, where it might bind worse.

So removing some material from the underside of the lever's tail, as Tim also suggested, seems to be the best fix. I'd already removed some material from the topside of the tail but I now suspect there's not a lot of extra height available on the top, so the underside is probably the best place to "thin the tail."

I've now removed a ton of material from the underside of the tail...well, at least 1/3 of the tail thickness documented by the Lever V4.4.STL model file, and the metal lever had quite a bit more thickness than the .STL / nylon printed lever to begin with, so there's no wonder the metal lever jammed! The nylon lever is slippery Taulman 680 (also quite stiff with a high transition temperature) so it doesn't cause a bind at full model thickness like the metal lever.

After countless filing and grinding iterations, there's now no binding with the metal lever and the bolt catch works with three quarters in the buffer tube. I'll thin the lever tail more and, hopefully, get it down to zero quarters before I break the SS with too much lever thinning!

whoisjohngalt

The returns from thinning the tail of the lever have diminished to zero. I thinned it considerably more than described in my last post, but there was no improvement realized and it still needs three quarters to not bind at all and function properly. It dawned on me that this is a nice 300 BO build with high quality parts (Brownells barrel, Toolcraft boron BCG, etc.) except for the buffer tube and buffer, which are cheap CDNN parts. I've had trouble with some CDNN parts in the past and I believe that a shorter than spec buffer or internally longer than spec tube would exacerbate this problem. I plan to try a quality name brand buffer and tube next.