DEATH IN THE AFTERNOON

I daresay the rhyme scheme of this poem has a specific name but if it has it escapes me. 
At lines 6 and 7 the end-rhyme-pattern commences and then runs in reverse, so that line 8 rhymes with line 5, line 9 with line 4 and so on until the final line rhymes with line 1. 
Why have I written it that way? 
I wanted to contrast the hunter's mounting excitement with the growing sense of dismay he experiences as a result of his action. 

 BLACKBIRD

With catapult, when school was finished,
I went to hunt in woodland, high
above Belfast, in summer light
and heard, among leafed branches spread,
a blackbird, singing like a bell.
I took aim, shot; the missile flew
unerringly, my aim was true.
With awful suddenness it fell,
all broken. Exultation fled,
to be replaced by sickly fright.
I knelt to watch it slowly die.
Within me somewhere, light diminished.



Now check out a popular radio tune from the 1950s featuring the amazing Ronnie Ronalde, one time resident of Guernsey. https://www.youtube.com/watch?v=trtxVvyzlrA