The pump handle and action bar should pull the Breach Block fully into battery. If it does not, you also will have a head space problem. Yours is a take-down and may well be subject to "wear and tear." I will go ahead and start the other discussion ...... Dry Fire with or without snap caps is not good for your shotgun.
I had toyed with the idea of doing Kirst gated, or Uberti factory conversions, but here in the Peoples Socialist Republik of Californication, I can only get one pistol every 30 days. Last month I got an S&W 9mm Shield, this month I got an S&W .38 Special Victory Model (WW 2 vintage). The would make it two more months out before I could even think of start shooting. Besides, here in CA, it make sense to go with the BP pistols and conversion cylinders.. They can be sold to others without dealers! Easy money in the bank.