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Extreme Long Range Hunting & Shooting (ELR)
First trip out with the 338/408 Imp.
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<blockquote data-quote="yorke-1" data-source="post: 1201273" data-attributes="member: 11960"><p>I got out today to start testing my new 338/408 Improved. Here's the build sheet for the rifle. I haven't decided what scope to use on there yet. After the picture was taken I threw one my Mk 4s on there but it looks a little small still. </p><p></p><p>- CheyTac M310 action (made by Lawton)</p><p>- Bartlein 30" 1-9.5" twist barrel (1.350" for 5" and straight taper to 1")</p><p>- Jewell trigger</p><p>- CheyTac Chassis (McRee Big Bore folder)</p><p>- Terminator T4 brake</p><p><a href="http://s162.photobucket.com/user/collegekidandy/media/B7D15BCC-AF40-4987-8E09-E258948A795A.jpg.html" target="_blank"><img src="http://i162.photobucket.com/albums/t260/collegekidandy/B7D15BCC-AF40-4987-8E09-E258948A795A.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></a></p><p><a href="http://s162.photobucket.com/user/collegekidandy/media/ACE44CE6-4F70-4D63-AE08-C888591FD90D.jpg.html" target="_blank"><img src="http://i162.photobucket.com/albums/t260/collegekidandy/ACE44CE6-4F70-4D63-AE08-C888591FD90D.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></a></p><p></p><p>I loaded 3 rounds each using 300gr OTMs and H 50BMG in 1 grain increments from 130 up to 135gr. I was a little surprised by the velocities I got. These were all recorded with a Magneto Speed V3</p><p></p><p>130gr: </p><p>Avg- 2943 fps</p><p>SD- 9 fps</p><p></p><p>131gr: There was one shot that came in at 2908 which threw the numbers. The other shots were 2971 and 2959</p><p>Avg- 2946 fps</p><p>SD- 33 fps</p><p></p><p>132gr:</p><p>Avg- 2927 fps</p><p>SD- 18fps</p><p></p><p>133gr:</p><p>Avg- 2980 fps</p><p>SD- 18 fps</p><p></p><p>134gr:</p><p>Avg- 2963 fps</p><p>SD- 7 FPS</p><p></p><p>135gr:</p><p>Avg- 3047 fps</p><p>SD- 8 fps</p><p></p><p>The initial velocity with the 130gr charge seemed in line with what I expected. The following charges are what have me a little stumped. All charges were hand weighed and bullets all seated withing .002" measured to the ogive. The fact that the SD on all of the loads is reasonably small given a case of this size is really throwing me off. The loads appear to be consistent, but the velocity just doesn't seem to track the way I expect. I will say that in my experience Bartlein barrels have always been on the slow side, especially their 338s. These velocities are just a little lower than I expected even with the 30" barrel.</p><p></p><p>I shot groups starting at 100 yards to zero the scope and then moved back a few hundred yards at a time with the final group shot with the 135gr charge at 1025 yards. The group at 1025 isn't bad but could be better.</p><p><a href="http://s162.photobucket.com/user/collegekidandy/media/971ABF05-B501-4A02-9F8C-15344BC3E61E.jpg.html" target="_blank"><img src="http://i162.photobucket.com/albums/t260/collegekidandy/971ABF05-B501-4A02-9F8C-15344BC3E61E.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></a></p><p></p><p>All of the groups were in the .5-.6 MOA range which is about as well as I was shooting any of the guns today (I was having an off day with all of them).</p><p></p><p>If anyone has some insight on the odd velocities I'd love to hear it. Next trip out I'll start at 135gr and work up a little more and see when I start seeing pressure signs.</p></blockquote><p></p>
[QUOTE="yorke-1, post: 1201273, member: 11960"] I got out today to start testing my new 338/408 Improved. Here's the build sheet for the rifle. I haven't decided what scope to use on there yet. After the picture was taken I threw one my Mk 4s on there but it looks a little small still. - CheyTac M310 action (made by Lawton) - Bartlein 30" 1-9.5" twist barrel (1.350" for 5" and straight taper to 1") - Jewell trigger - CheyTac Chassis (McRee Big Bore folder) - Terminator T4 brake [URL=http://s162.photobucket.com/user/collegekidandy/media/B7D15BCC-AF40-4987-8E09-E258948A795A.jpg.html][IMG]http://i162.photobucket.com/albums/t260/collegekidandy/B7D15BCC-AF40-4987-8E09-E258948A795A.jpg[/IMG][/URL] [URL=http://s162.photobucket.com/user/collegekidandy/media/ACE44CE6-4F70-4D63-AE08-C888591FD90D.jpg.html][IMG]http://i162.photobucket.com/albums/t260/collegekidandy/ACE44CE6-4F70-4D63-AE08-C888591FD90D.jpg[/IMG][/URL] I loaded 3 rounds each using 300gr OTMs and H 50BMG in 1 grain increments from 130 up to 135gr. I was a little surprised by the velocities I got. These were all recorded with a Magneto Speed V3 130gr: Avg- 2943 fps SD- 9 fps 131gr: There was one shot that came in at 2908 which threw the numbers. The other shots were 2971 and 2959 Avg- 2946 fps SD- 33 fps 132gr: Avg- 2927 fps SD- 18fps 133gr: Avg- 2980 fps SD- 18 fps 134gr: Avg- 2963 fps SD- 7 FPS 135gr: Avg- 3047 fps SD- 8 fps The initial velocity with the 130gr charge seemed in line with what I expected. The following charges are what have me a little stumped. All charges were hand weighed and bullets all seated withing .002" measured to the ogive. The fact that the SD on all of the loads is reasonably small given a case of this size is really throwing me off. The loads appear to be consistent, but the velocity just doesn't seem to track the way I expect. I will say that in my experience Bartlein barrels have always been on the slow side, especially their 338s. These velocities are just a little lower than I expected even with the 30" barrel. I shot groups starting at 100 yards to zero the scope and then moved back a few hundred yards at a time with the final group shot with the 135gr charge at 1025 yards. The group at 1025 isn't bad but could be better. [URL=http://s162.photobucket.com/user/collegekidandy/media/971ABF05-B501-4A02-9F8C-15344BC3E61E.jpg.html][IMG]http://i162.photobucket.com/albums/t260/collegekidandy/971ABF05-B501-4A02-9F8C-15344BC3E61E.jpg[/IMG][/URL] All of the groups were in the .5-.6 MOA range which is about as well as I was shooting any of the guns today (I was having an off day with all of them). If anyone has some insight on the odd velocities I'd love to hear it. Next trip out I'll start at 135gr and work up a little more and see when I start seeing pressure signs. [/QUOTE]
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First trip out with the 338/408 Imp.
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