I don't post much here so I hope this is the correct section. I have a Savage 12 FV in .223. For the 1st 600 or so rounds I have not had a single issue with the gun. Now I am having keyholing problems with 55gr varmint nightmare extremes. When I shoot them 1st bullet from a cold barrel will keyhole and then the next 4 will group(often times around or though the sideways bullet hole). At 1st I thought it was a copper fouled barrel so I cleaned it with wipeout and didn't get a lot of blue out. After some reading I thought it might be carbon so I used Hoppes #9, KG1, and wipeout(not that great for carbon). I cleaned the barrel until the patches were colorless when passed through the bore. I took the rifle out to the range this weekend and the first 12 shots were fine and then after the rifle cooled for 30 min the 1st round keyholed followed by a four shot group. I let the rifle cool and again the 1st shot keyholed followed by another nice 4 shot group. Now I am not sure it is a cleaning issue at all. It seem like a temperature issue or bullet issue but I would like to know what everyone else thinks. I have shot 55gr sp, 69 sierras and 75 a-maxs without issue. Thanks in advance for all the help
