Hi Peter, here is the today new tests with 13 to 14mm of free hull space qith Z2M wad without pressure!!!
Look also my ballistic results, with MBx32 powder
MBx32 249/11 - 12/67.40 - 1.70x33gr/N.8 - Aquila 22 - * - 56.00mm
- PMax 751 bar - V2.5 418.9 m/s - V10 292.8 m/s - TC 2611 usec - RT 394 usec - Int 0.577
- PMax 762 bar - V2.5 420.3 m/s - V10 302.5 m/s - TC 2574 usec - RT 338 usec - Int 0.592
- PMax 778 bar - V2.5 420.0 m/s - V10 312.5 m/s - TC 2595 usec - RT 384 usec - Int 0.588
- PMax 792 bar - V2.5 422.1 m/s - V10 306.0 m/s - TC 2520 usec - RT 279 usec - Int 0.590
- PMax 829 bar - V2.5 423.9 m/s - V10 300.9 m/s - TC 2486 usec - RT 304 usec - Int 0.595
Average
- PMax 782 bar - V2.5 421.1 m/s - V10 302.9 m/s - TC 2557 usec - RT 340 usec - Int 0.588
So, if you consider that I have put the CX2000 primer and not the 686/615 primer for that setup, you will probably understand why I lost the residual velocity on V10!!!
Kind regards!

Nikos - Greece - Idiogomosi Reloader Cal.12 - Mec Grabber/9000/650 modded + Gaep 3 pistons modded + Cortini 4 pistons modded + Cortini 5 pistons + 5 x 5 stage super precision prototypes designed by me