Had the same thing with Mangum and Mosin.

Same issue with M4, however standing. See attached video:

http://www.youtube.com/watch?v=JZpX55Q2N7I

Edit: Windows 8 64b

Several issues with this behaviour, really needs more attention.
See video:

http://www.youtube.com/watch?v=u3ioOZQ_i98&feature=youtu.be&t=45s

lol @ the 1 downvote.

someone always has to be that guy

This has ruined my surprise attacks many times and forced me to either relocate or take shots.

confirmed, was outside the powerplant at elecktro, Mosin, LRS, Bipod, ammo all pristine, bullet hit the ground every time unless i was crouched instead of prone even when i dialed the scope up to 800 which should have caused my barrel to lift compared to looking at the same spot with a 200 hold

it seems to especially happen on hills

Hello,

this is a known issue and we are already working on a fix. We appreciate your feedback however!

Thank you!

Hills & Trees are the enemy..

Please fix ASAP, was just killed due to this bug.

This bug needs a lot of attention. You can't shoot at people on the ground, by trees, by buildings.... I've hit invisible walls in the most random places. It appears a blade of grass is a barrier at times.

I've been standing up, shooting downhill along a trench and hit some type of wall. This makes good terrain, ambushing, etc... pretty useless.

I sincerely hope this is being treated as a top priority. Game breaking bug in my opinion.

There have been some adjustments made on the internal build. This issue should be fixed with the next experimental update (0.42).

Leaving this open until players can confirm the issue being fixed.