My experience with CheckMate & my CCO were mixed. One of the OEM mags was OK, the other was nearly unusable. Though there was some improvement with use.
I also had a used (I mention "used" because I'm not entirely certain they are OEM.) PM7 40 that came with Metalforms. They sucked...period. I replaced them with MecGars because .40 S&W Wilsons were unavailable. They worked well.
Sadly, even with a premium product such as Dan Wesson, Mags are still the weakest link. Hunt down some Wilsons or Tripps and things should be fine.
MSgt, USAF, Retired
NRA Life Member
The hardest thing to explain is the glaringly evident which everybody had decided not to see. - Ayn Rand