I grabbed this image by Chris Bristow from the same EF thread and matched both rulers directly and this perfectly illustrates why you must take into account basic photogrammetry principles when comparing objects. The differences between the intervals are proportionally opposite to each other.
Ray Mitcham originally said that the following comparison was proof that the rifle straps were on opposite sides, then it was pointed out that the EXIT sign was reversed? DOH!
Anyway it's clear that the angles and rotation of the rifle in both photos are not a direct comparison and like the above ruler example, photogrammetry allowances must be applied. This isn't as easy as it seems.
JohnM