I recently picked up a CTR high Blitz Needle. I was using an ASI high Blitz Needle before. I immediately noticed that I wasn't able to shield-block as quick as before. The Blitz Needle with no ASI takes a split second longer to get through the reload animation at the end of a charged attack.
I didn't realize that ASI affected the reload animation at the end of a charged attack, so this got me killed during a Vanaduke run since I wasn't able to block in time.
it doesn't speed up the reload animation technically, but it does speed up the animation where you bring ur gun up and down. at least you can charge faster now