I have Leupold Competion scopes on my springers, but have used big Nikko's with no problem at all. Same set up as you....AJP rail with standard sportsmatch mounts, never had one move.
Some of the lads on the FT scene use Busnell elite 8-32x40 the older front PA model to very good effect,,Brian Samson, the current springer world champion being one of them.
Don't put a big Nikko on an SR TX.
The Pope HW97 V-Mach. Gary Cane Laminate stock. Leupold Competition 40 mag Mildot.
The Smiler. Walther LGU. WE Laminate stock. Leupold Competition.
The Dark Destroyer. TX200 MK3. Leupold Competition 40 mag.
Pro-Sport. Warren Edwards Blue Laminate stock. Bushy 8-32x40.