Recently I have bought HS Precision rifle in 338 Lapua Magnum caliber thinking that HS will give me better combination then Blazer R93 with 7 Rem Mag which I normally use for longer than usual shots. Unfortunately with 4 different types of bullets and different types of loads first 7-10 shots make very nice groups but after that groups start to go loose. I cooled the barrel obviously, try different loads and cartridges types but it is still the same result. I decided to clean the barrel after 7-10 shots but broke the extractor and have to wait to get a new one. Are anybody has the same experience? What it could be? Is it supposed to be like that?