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Rifles, Reloading, Optics, Equipment
Reloading
Somehow I'm going way too fast with not enough powder?
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<blockquote data-quote="EXPRESS" data-source="post: 1226786" data-attributes="member: 1441"><p>In my .338 win mag, 26" barrel I noticed that after about 250-300 rounds that the load I was using had "sped up". It was a fairly hot 75.5gn of VV N160 pushing a CEB 225 at 2880fps. It went up to around 2960fps. So I dropped back to 71 grains and MV went back to 2880fps. This load had shown some pressure signs with flattened primers, but I hear that it is very common in the Blaser R8 rifles, and this one seems to have a large chamber.</p><p></p><p>Now I've been testing 300 grain Bergers in the same .338win. </p><p>My first tests with VV N560 gave a mv of 2483fps av with 68 grains. Consider that 65 to 72 are the published parameters. With 72 grains I got 2618fps av! That is 338 Lapua territory!</p><p>These loads are all about 1mm off the lands, all FL sized cases, charges are weighed on a RCBS beam scale, which is regularly checked and zeroed. </p><p>Velocity was measured using a Magnetospeed and Chrono simultaneously, with the chrony giving speeds of a dozen fps more than the Magnetospeed. I have junked the Chrony...</p><p></p><p>And all this with no discernable pressure signs. </p><p></p><p>I settled on 68 grains because velocity is acceptable but above all accuracy is phenomenal, shooting into a single ragged hole. Even at 72 grains and 2600fps it's shooting sub MOA, but I just can't get my head around the idea of safely pushing 300 grains at 2600 in a .338 win mag? </p><p></p><p>Has anyone ever seen this kind of speed from this cartridge in a 26" barrel?</p></blockquote><p></p>
[QUOTE="EXPRESS, post: 1226786, member: 1441"] In my .338 win mag, 26" barrel I noticed that after about 250-300 rounds that the load I was using had "sped up". It was a fairly hot 75.5gn of VV N160 pushing a CEB 225 at 2880fps. It went up to around 2960fps. So I dropped back to 71 grains and MV went back to 2880fps. This load had shown some pressure signs with flattened primers, but I hear that it is very common in the Blaser R8 rifles, and this one seems to have a large chamber. Now I've been testing 300 grain Bergers in the same .338win. My first tests with VV N560 gave a mv of 2483fps av with 68 grains. Consider that 65 to 72 are the published parameters. With 72 grains I got 2618fps av! That is 338 Lapua territory! These loads are all about 1mm off the lands, all FL sized cases, charges are weighed on a RCBS beam scale, which is regularly checked and zeroed. Velocity was measured using a Magnetospeed and Chrono simultaneously, with the chrony giving speeds of a dozen fps more than the Magnetospeed. I have junked the Chrony... And all this with no discernable pressure signs. I settled on 68 grains because velocity is acceptable but above all accuracy is phenomenal, shooting into a single ragged hole. Even at 72 grains and 2600fps it's shooting sub MOA, but I just can't get my head around the idea of safely pushing 300 grains at 2600 in a .338 win mag? Has anyone ever seen this kind of speed from this cartridge in a 26" barrel? [/QUOTE]
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Somehow I'm going way too fast with not enough powder?
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