SB tactical PDW+aero lower won't collapse

[stage20]

The rods on the PDW get into the lower just before it collapses all the way. Just seems there is a lot of material around the buffer area on the lower.
Std x15 lower.
Is this combo a known issue? Thought I had it installed crooked. Loosened the castle nut and tied to center. Both rods are hitting on each side.

 

[JWlineman]

Wouldn't think this would happen on a standard lower, maybe their "enhanced" lowers. Never messed with a PDW, any chance the mount could be off center?

 

[stage20]

Why I loosened the castle nut and tried to collapse again to try and center itself. There is interference. Cerekoted noveske bazooka green and the brace is FDE. It was going to look so sweet. I don't know now.

 

[JWlineman]

Typical...
Although it should still slide even with the coating.

 

[Anangrypasta]

Got any pics? I had mine on an Aero before I traded it, and it was a fine fit! It really liked pulling my cheek hairs off though lol

Does it work okay off the gun? Any weird wear marks on the brace arms?

 

[stage20]

I'll get some shots tomorrow if I can get the right angles. It's like it's locked into the 2nd position. Won't go any further. Brace works great off the lower. I need to get my mic out and measure this lower