Speaking from experience, the Mark V leaves a very distinctive mark... and that is it. I can't see it on the left, but the case on the right definitely has it. Not only that but primers while subjective, don't look that great either. Definitely a pressure issue.

In addition to the items already mentioned have you checked your distance to the lands? I doubt you'd be able to reach them and still fit in the magazine but stranger things have happened. I just want to make sure that you're not right up close to the rifling, or touching. That could cause you some problems. Are the cases the proper length? If they're a little long and the neck is running up into the throat area they could be getting squeezed/pinched. I doubt that happens all that often, but I know that it happens.

You should be just fine with that length, but be advised that just because that length will fit the magazine does not mean the cartridges will feed.

Distance to lands and Weatherby shouldn't be in the same sentence.

Okay so I just did the marker on the bullet to see my seating depth on the 160gr accubond in my markV. I did it 3 times and it was 3.852 each time. I tried to go .015-.03 back but it wouldnt fit in my mag. The longest I could fit was 3.722 coal. I am guessing its okay to start from that coal even though the book says 3.6 max?

You can also see pressure on the case on the left at the "S" with your 82.5 load. It's a warm load also. I would be using Retumbo or even H50BMG powders. The Magnum powder is very sensitive to temp change. A load safe in the winter could easily be over pressure in the hot summer. I have experienced this, and do not use this powder for that reason. The bigger the case, the more powder it has to effect the temp changes.