I used them for about 5 years, I added a bit extra Bore Butter and shot them with a 240 gr lead bullet and 100gr of RS. The groups Averaged about 1.5 to 1.7 inch at 100 yds and I never cleaned the gun till I got home. The do have their points, the one limitation is the load the design just wont work as far as I know with more than 100gr RS or equevilant[ 90 of 777- FF ].
Within their limitation on the 100gr load they did an excellant job for me I took 8 deer with them,if they would work with a bit more powder I would still be using them, this wiping every shot is a pain. Lee