Never chronoed it.  
The smith that built it, has built many, says its right at the 4000 mark, just under.  
However, I was corrected on here by some of the tech guys when I made that proclaimation.  So, I dont know for sure.   Its fast enough.  I can attest to that.  
 
Actually, it shoots great when fire forming.  Cant tell alot of difference.  Another thing I like is I can shoot the 75gr VMax and the 100gr Partition, and it doesnt change the 0 enough to mess with.  Right there.  
Andy