When I shot pistol I shot a lot of silly wets with my 686 with both 180gr RCBS GC and RCBS 158gr GC and found no gain in using gas checks accuracy wise, but those days I had not heard of Hi-Tek, I also shot a lot of steel challenge with my 45 Auto and 230gr RCBS gas check design, I actually found much better accuracy with that bullet without the checks as many others also did. I still have that 230gr mould and I have removed the gas check ring and it shoots a dream in brothers 45 auto and his 460 SW. I don't claim to know it all but Hi-Tek has improved the accuracy of all loads I use and I don't have to deal with greasy lubes any more. I also believe that Hi-Tek allows the use of alloys that may have been marginal in the old lube days. I also think powder selection is more important than gas checks. A lot of what we all knew before Hi-Tek is no longer relevant in my view. I have cast some 320gr plain base .452 for my brothers 460sw out of 50 50 clip on and stick on wheel weights with no extra tin to see what difference it makes to present loads, I am tipping none. Regards Stephen