A relative of mine recently back into guns who is absolutly meticulous in what he does says the work is 3rd world and a disgrace. I who am not meticulous quite like those blocks and even though i also like the screw in back block of the 77 etc can dismanlie the 99 back block quicker. The lack of preload means you only need 2 blocks in one either side, even though I use them all.