I noticed sprue marks on my S&W 638s barrel and thought this was an investment cast part. By accident I found out that it is a MIM part. Is this safe ? Look up PARMATECH on Youtube. They seem to supply parts for Smith and Wesson. Watch the video and you will see several parts - hammers,triggers,sears,rail blocks for the M&P pistols and a Stainless J-frame .38 special +P S&W barrel ! Anyone know how long this has been in use ? The hammer and small parts that are MIM dont bother me, but the barrel ? Come on?