There are signs of higher accuracy/precision by using the Tenex piston on three cheap ammo types. TopShot, CCI Std and Geco. I think the geometry on the Tenex bullet from Eley are shaped like that for a reason and that reason is higher accuracy/Precision.
Here are TopShot testet on 50 yards. First 2 x 5 shot on top with original bullet, and the seria down to the right is after pressing with the tenex piston.
I dont claim this tool will make crappy ammo into match ammo, but it seems to improve a bit. Tenex piston increase diameter on the bullet from 5.690 mm to between 5.695 mm - 5.700 mm.
Deep Hollowpoint piston increases diameter on the bullet from 5.690 mm to between 5.700 - 5.705 mm.
Supershock increases diameter by 0.005 mm.
I have a personal impression that a little increased diameter on the bullet will in some guns help a lot on the accuracy/Precision, but I have no Scientific proofs of it.
The material beeing used is steel.
You can use the tool to make good ammunition without hollowpoint into hollowpoint ammo.
You can increase accuracy/Precision With the use of the Tenex piston.
You can make ammo expand extremely so you can use it to hunt pest indoor.
You can use ammo that expands extremely to kill game cought in traps without destroying the trap from the bullet going straight through the game and the trap.
You can also use it for FUN!
Orange shot at 50 meters With Maximum hollowpoint in TopShot.