Some years ago , a Russian developed a barrel configuration that had five lands and grooves instead of the , then common four . After some experimentation the five "Lands" were radiused , and the "squared" corners taken off . This appeared to significantly improve accuracy , and reduce break-in time , along with the barrel being both easier , and faster to clean . Thus the designation 5r , or 5-radiused (lands) . When this barrel style first came to the U.S. , most thought it stood for 5-russian . Not correct . A famous gunsmith / shooter brought the 5r style to this country in the late 50's/ early sixties , and dominated in his discipline for several years . Currently ; Brian Blake , of Blake Barrels in Phoenix is turning out a 6r style barrel , believing the 6 lands reduce pressure and drag on the bullet . And his barrels are winning many events throughout the country , by top shooters . I know this to be true because the guys , and Ladies are beating me .
Regarding "X" count . F-class targets have the usual scoring rings as other targets , with one exception . The "Center" ring , or Bullseye is called the "X"-Ring . It is 1 MOA in diameter , in relation to the distance being shot . A 600 yard F target for the TR , or Open class has a X-ring of approximately 3" in diameter . About 5" in diameter for "Sling" shooters . Just like the 10 Ring , it also has a point value of 10 points for score , but it is also used to designate a Match winner .
Example : Two shooters tie in score after 3 relays of 20 shots for record . Both shooters score a matching 598 out of a possible 600 points . The scorekeepers then count shots within the "X" ring to determine the Match . The higher "X" count is determined the winner . It is extremely difficult to shoot a 200 - 20X , "perfect" score , but it does happen more than most think . I've managed to accomplish this feat four times in five years , and once during a certified NRA Match . To put that in perspective ; I've fired over 40,000 rounds in both practice and competition , during that period . And my wife is asking if I want my mail sent to Ben Avery .
