Reply To: Did I purchase correctly? I know, VERY SUBJECTIVE
Shroud ext= $49
AR stock kit= $79
Internal mods are opened up transfer port and barrel port with heavier hammer spring. Tuned to 17fpe for 24 shot below 4%ES. Lapped the barrel polished up crown and leade as well as deburr the hammer and airtube. Polished hammer and where it rides in the airtube.