Well, I suppose if you expected your carrier to be fired upon by the standard .303BRIT round, it may be reasonable to perform a proof test to that standard. A .303BRIT standard bullet would have a jacket made of a material that encases a lead core. Could one expect the adversary to be equipped and shooting at you with 7.92x57 or perhaps 7.7x58 ? Those rounds would likely be fired from a distance and angle other than what we see in the LP2A. Close range and at right angles would be a worse case scenario. Not to mention 20mm Solothurn ... Quite interesting Nathan. I do not doubt the possibility that a rifle round may have created the mark shown: I am simply intrigued that it enters production.
Why would a factory invest time and material to produce an armoured vehicle without having knowledge ahead of time that the material meets standard?
It is a common practice to test assorted armour under simulated field conditions on post production items, in particular at set periods of time during service life. Once the armour has been struck by a round, it is not deemed appropriate to return the item to stock for service issue.
Here is an image showing an example of a heat treated Canadian Universal Carrier side plate, displaying what I believe is the hardness test dimple,(
update, not from a bullet strike) along with strike marks left from the straightening process, and the control or registration number of the production plate. The number is not related to the lower hull number, upper hull number, serial number or WD number. On the sample shown, the opposite side plate of the Carrier has a non-sequential number.
There are numerous wartime examples showing Canadian Universal Carrier armour was defeated by enemy small arms fire. Here is an image of a captured Canadian made MKI* that has gone through the retrofit program to the MKII UCW standard. You can see the side plate has been struck at an acute angle and defeated. June, 1944, France. Ignore the red circles, they identify the deep wading plate pads over the MKI* folding armour.
As a side note, you can see this Carrier being driven by the adversary, as it is brought along side of a Sherman. See minute 7:49 in:
http://www.youtube.com/watch?v=Dpb9_YS3CzE