I posted earlier about using blackhorn 209 and experinced some serious blowback from my mk85. I know that gun does not have the correct breech plug but where exactly is the blowback occuring? I was using blackhorn and had just converted my gun to 209 primers. The week before I was using my normal musket cap,100 gr of triple 7 and a 270 gr powerbelt without any blowback at all. My brother talked me into using a pack of precision elite hp 300gr bullets which seat much tighter then the powerbelts. I was feeling a fair amount of blowback using this bullet with 100gr of triple 7. Isa certain amount of blowback normal? I have shot this gun for years mainly using 45 cal speer hollowpoints with knight sabots using pyrodex and then switching to powerbelts about 3 year ago and never remember blowback issues at all.Thanks for any input.