Originally Posted by Darron
I'm not so sure Mart, I first used a known good batch of 4.52 in the FTP , I was shooting groups at 55 yards with Keith Hassell when he said try these 4.53 , I did and groups instantly went from 50p size to pinging a drawing pin. It could be that they were just an even better batch than the the 4.52 but I get the same results on different batches.
Air gauged JSB pellet head size distribution. no.3 = 4.49mm. no. 6 = 4.50mm. no. 10 = 4.51mm. no. 15 = 4.52mm. (source
Could be a number of things but I've pretty much come to the conclusion that 4.XX means nothing but not to be confused with batches.