I run a couple of Mods from Colin ( onelesscharlie ) on my .243 .223 .17HMR, as he is a personal friend he has asked me to test these and others from time to time. I can say that they perform brilliantly and the quality is top draw. Mike Powell from Sporting Rifle tested one in last years mag and also gave it good reviews. I have eneded up getting rid of my Wildcat mods and buying them from colin for my range of rifles. I am happy with them and they have had some serious use, only gripe is he didnt give me mates rates when bought them !!! no complaining realy ! HIGHLY RECOMMENDED !