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Rifles, Reloading, Optics, Equipment
Reloading
300 Win. Mag. barrel life.
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<blockquote data-quote="Bart B" data-source="post: 1124332" data-attributes="member: 5302"><p>When the .300 Win Mag was popular in 1000-yard prone matches, those using one to win and set records got about 1100 to 1200 rounds of accurate barrel life. That's based on them testing 15 to 20 shots in 5 to 7 inches at 1000 yards when new but opening up to 8 to 9 inches at that round count. That's about a 50% increase in test group size which has been a popular standard for competitive rifle shooters for decades.</p><p></p><p>I've measured throat erosion in three .30-.338 Win Mag match barrels over their 1200 to 1300 round barrel lives. They all eroded away about .001" for every 15 to 20 shots fired. Bullets needed to be seated about .070" further out at the end of barrel life to gently set back by the rifling when chambered. Therefore, I think a .300 Win Mag will wear out its barrel a bit faster as it uses 5 to 7 grains more powder for a given bullet weight compared to the .30-.338.</p><p></p><p>No barrel shoots as accurate 1500 rounds into its life as it did when new. But the way a lot of people test them, I understand why they will come to a conclusion they shoot the same accuracy at that many rounds of barrel life. Sierra Bullets uses a .300 Win Mag test barrel checking their 30 caliber match bullets 190 grains and heavier for accuracy. They start out probably 1/4 MOA average at 200 yards with their reference lot of bullets, but the last I heard from them, when it gets to about 1200 rounds, it's opened up about 50% to 60% to around 3/8 MOA average. But that keeps their accuracy extreme limit under 1/2 MOA at 200 yards for all their match bullets. Sierra uses a .308 Win test barrel for ligher match bullets and get the same accuracy standards but a 3000 round barrel life is typical.</p></blockquote><p></p>
[QUOTE="Bart B, post: 1124332, member: 5302"] When the .300 Win Mag was popular in 1000-yard prone matches, those using one to win and set records got about 1100 to 1200 rounds of accurate barrel life. That's based on them testing 15 to 20 shots in 5 to 7 inches at 1000 yards when new but opening up to 8 to 9 inches at that round count. That's about a 50% increase in test group size which has been a popular standard for competitive rifle shooters for decades. I've measured throat erosion in three .30-.338 Win Mag match barrels over their 1200 to 1300 round barrel lives. They all eroded away about .001" for every 15 to 20 shots fired. Bullets needed to be seated about .070" further out at the end of barrel life to gently set back by the rifling when chambered. Therefore, I think a .300 Win Mag will wear out its barrel a bit faster as it uses 5 to 7 grains more powder for a given bullet weight compared to the .30-.338. No barrel shoots as accurate 1500 rounds into its life as it did when new. But the way a lot of people test them, I understand why they will come to a conclusion they shoot the same accuracy at that many rounds of barrel life. Sierra Bullets uses a .300 Win Mag test barrel checking their 30 caliber match bullets 190 grains and heavier for accuracy. They start out probably 1/4 MOA average at 200 yards with their reference lot of bullets, but the last I heard from them, when it gets to about 1200 rounds, it's opened up about 50% to 60% to around 3/8 MOA average. But that keeps their accuracy extreme limit under 1/2 MOA at 200 yards for all their match bullets. Sierra uses a .308 Win test barrel for ligher match bullets and get the same accuracy standards but a 3000 round barrel life is typical. [/QUOTE]
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Rifles, Reloading, Optics, Equipment
Reloading
300 Win. Mag. barrel life.
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