Anyone who flies 30mm birds often has probably run into this before. There's been numerous threads started about this issue, but very few films. You earn that sweet tater shot on a Spitfire only to have him shrug off the hit with minimal to no damage and fly off as if nothing happened.
In this case the lucky Spit14 takes a fuel leak after being hit by a 30mm round from within d200... 
http://dasmuppets.com/public/Scotch/SPITTATER.ahf
I was running into this left and right, last night. Although, unlike your Swallowfire (TM) which suffered at least some damage, my 30's were consistently registering zero damage.
I suppose I should start filming. Just last night, I scored (visually) hits on two Spit 16's with no discernible damage (one of which was a clear wing strike), a single hit on the nose of a P51 with no damage and what must have been a dozen strikes against a B24 with *nothing* even falling off.
The 24 was particularly interesting because the hits were long range (long enough that the standard hit sprite was shown instead of the burst, 500+? - and no I wasnt firing the 13's - and they were all concentrated in the tail section). Nothing. Not a darn bit of damage. And I DID get an assist when we went down later so at least some of the hits actually registered server side.
Since this comes up fairly frequently - I wonder if HT might chime in with some theories as to why this is happening?
Not angry about it - but it would be nice to know, if it is a client-side issue, how one might go about fixing it.