The solid copper bullets leave a mess
I remember when Barnes was first pushing there bullets that it was a problem with them leaving lots of copper in the bore. They were formed using soft copper due to them not having a soft lead core. I thought that there was also problems with the Barnes TTSX bullets leaving more copper deposits then say a Nosler ballistic tip or Partition bullet. The story that I remember was that Barnes used pure copper instead of the alloy that bullet manufactures normally use. The solid alloy bullets from Nosler and Hornady use basically jacket alloy without the lead core. I would like to buy a box of the Barnes TTSX bullets, but don't want to have issues getting the copper fouling out using standard cleaning methods. I know that Barnes added the groves into their bullet to lower the pressure of the bullet in the bore without a compressible lead core. This might also mean that they have gone over to an alloy of copper, and is no longer pure copper.