I just bought several boxes.
The velocity in the Remington 5R would probaly show 2890fps average, if he set up his chrony at a standard 15 feet from muzzle. If you check 762NATO spec, I believe the velocities are given for 2" shorter barrel and taken at 78 feet from the muzzle. The REM700 5R has a 1/11.2" twist rate versus 1/12" for most NATO rifles which the original spec load was developed for, which should show a slight velocity increase and pressure gain. I throwing this figures out off top of my head. If anything is off the chart, please correct me.
The split case looks like a brittle steel case for sure. I can't see any other reason for it to split in that region longitudinally. I'm sure his 5R has a nice tight match chamber .308WWin dimensions, so we may see splitting likewise if our M-14's have NATO dimension chambers, being a little more generous than .308Winchester.
I'm going to fire these, keeping an eye on velocity and pressure. I'll try to remember my chrony, and I'll shoot at NATO spec distance from muzzle, to see if indeed it is producing M-80 ball velocities. and I'll post if something looks out to lunch. Some large firing pin holes can produce tiny craters in primers, which should not be looked at a excessive pressure by itself, without a flattened primer filling the pocket along with it, and knowing the composition of the primer hardness as a baseline to compare.
The charge weight seems light for the round, I believe the US ammo uses 46 grains????, based on a 150gr projectile for 2750 in a 1/12" twist barrel at 78feet. They may be using faster powder, like the video mentioned, to save on charge weight's/ cost's per round,, but it may produce higher port pressure, and more abrupt cycling.
Great video he did there,... and thanks for posting it. I love when someone document's there finding's like this. Bravo!!!1
