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308sako
03-16-2008, 12:45 AM
Easy shot... right


http://i181.photobucket.com/albums/x160/308sako/DSCN0044.jpg

As posted elsewhere, this testing is with the 175 Berger BT Match bullet. The powder is IMR 4064 and the brass is Lapua, the primers Federal 210M. Seating depth was set to 2.825 COL for this run, but (brace yourself Jethro) the rifling contact begins when seated to approximately 3.0". Yes that means .175" of jump... outrageous you say... so do I, Thanks Remington.

Unfortunately the Oehler 35P failed after the last fouling shot... suffice to say these loads should be traveling between 2500 and 2600 ft/secs. There was a full grain of powder difference between the Load #1 and Load #3, and the comeup between 300 yards and 410 yards was projected to be 13 clicks or inches... I used 10 not to superimpose the groups.

Important note on group size... these are the outer dimensions... no bullet diameters deducted as yet.

Load 1 - 300 yards group is 1.831 high 2.068 wide all dimensions outer edge to outer edge
http://i181.photobucket.com/albums/x160/308sako/DSCN0048.jpg

Load 1 - 410 yards group is 1.172 high 3.169 wide
(first three touching .842, best 4 - 1.376)
Yes, I choked on round #4.
http://i181.photobucket.com/albums/x160/308sako/DSCN0053.jpg

Load 2 - 300 group is 1.664 high 2.479 wide

http://i181.photobucket.com/albums/x160/308sako/DSCN0049.jpg

Load 2 - 410 group is 1.983 high 3.268 wide

http://i181.photobucket.com/albums/x160/308sako/DSCN0052.jpg

Load 3 - 300 group is 1.555 high .975 wide

http://i181.photobucket.com/albums/x160/308sako/DSCN0050.jpg

Load 3 - 410 During this string, the wind was quite variable left to right

Group is 2.112 high 4.280 wide

http://i181.photobucket.com/albums/x160/308sako/DSCN0051.jpg

I am about to load the second test batch and am thinking along the lines of loading to contact length the same loads as fired with the massive amount of jump. Thoughts are same brass, primers and powder, just .175 longer. The charges were well below book maximums, but did show some pressure on the primers.

I have partial sized the cases in a Redding F/L bushing die, using three different bushings to ease the necks back down. Fired necks are about .345, so a .340, .366, and a final .333 were used. The loaded neck dimension is .3365. The "partial sized" method allows a small shoulder to form on the neck aiding in concentricity (compensating for the gross factory chamber.)

Appreciate any feedback or input to help this project along. Thanks in advance.