Things I liked:The Ultra loads easily, fires smoothly, and has the blend of weight and ballance to makes it a hoot to shoot! Things I would have changed:My Ultra needed several improvements to make it the fine shooting instument it has evolved into: polishing the rifling to a precise 8.95mm consistency, removing rifling in the breech that was cutting the bolt o-rings, and bevelling the lip of the barrell air inlet to allow for concentric seating of bullets without shaving lead off their lower edges. The factory o-rings for the sliding bolt seal lasted less than 200 rounds, and after some experimentation were replaced using staged 1.9 mm thick o-rings (4.8 I.D. followed by 5.8 I.D.) in order to seal the breech up tp the 2600 psi optimum pressure for this rifle. Fill the o-ring grooves with sticky silicon grease prior to slipping the o-rings on. What others should know:As other reviewers indicate, this is a rifle for experienced pcp airgunners who have the skill to understantd the mechanics of the wheapon - or who at least have access to someone who does. The 102 grain cast Lee bullets work well, but the Hornady .36 cal roundballs are a breeze to use and are just as accurate, so why waste time melting lead when you could be out shooting for around a nickle a ball. Also, for quieter, slightly more accurate and for comparable downrange energy, shoot 60 grain Aguilla .22-SSS ammo from a quality bolt action rifle - but there will be no kick and not nearly as much fun!