Originally Posted by 5teve L
Dave, the breech on the MPR & the S400 are different mate, the MPR barrel is thicker & therefor the breech is machined slightly different ot allow this. (thats my theory) Because as you say the aim points are indeed different, I think with my old mounts the scope to barrel on the MPR was 2" & on my old 400 was 1.75"
There are two different breech blocks on use on the S400's they changed to a 2mm higher version nearly two years ago, I'm not sure this will make a lot of difference.
Don't forget the relative angle on the barrel & scope as well