Like Slim said, be sure you are using pistol primers, not rifle primers. CCI are the hardest primers, Federal are the softest, Winchester somewhere in between. I don't know where Remingtons fit in the hardness scale.
If you haven't had any problems setting off factory shotshells with 209 primers, then the shotgun is probably fine and you shouldn't have any problem setting off the pistol primers in the brass shells.
If you have any shells that are not loaded, you can experiment with primers and seeing if you can pop them without having to shoot loaded ammo.
Good luck.