This is a direct quote from PSA from ARFCOM
Front and rear take down pins (longer)
The bolt catch (larger)
The Mag catch
The carbine buffer tube (longer)
Carbine and rifle buffers (shorter)
The PA10 stripped upper receiver is low profile, but the PA10 configuration is mostly proprietary. We can only guarantee that PA10 parts will be compatible with other PA10 parts.
Also the uppers and lowers are not AR10/LR308 compatible a PSA PA10 upper will not fit on a DPMS/Armalite lower vise versa with PA10 lowers and DPMS/Armalite uppers.