Of course, he can make one shot and:
- firstly it will be surrounded, tanks are usually moved by a group and will be destroyed by another tank
- Secondly, the tanks are usually accompanied by infantry, so the infantry will also try to destroy the crew, and notice the infantry's chances are very good 200 meters from the cannon.
- in the third, the loader will have to leave the shelter and load the cannon on the barrel, this will unmask the cannon and the loader most likely the dubet is immediately killed
may not be entirely correct, but here are historical footage from the PAK-36
Report tell a different story, according to The History of the Panzerjäger.
On 3 March 1942 the Panzerjäger got 2 Pak38 with Stielgranate, who where facing soviet heavy and Super heavy tank other weapons could not defeat. The Stielgrenate managed to destroy 2 of them and the Panzerjäger began to regain trust in their weapons.
According test that took place on 3 March 1942
"all 6 round hit and did destructive impact on T-34s"
Conclusions:
"The new Stielgranate 41 will allow the 3.7cm PAK, to be used as an effective ambush anti-tank gun against enemy tanks."
The rate of fire was low. In order to reload the weapon the would turn the barrel to left and the Stielgranate was load from the prone position. But this is rather irrelevant since it was used as ambush anti tank where it was all about the first shot.
The weapon was effective when operate by experienced crew and it was given to Fallschirmjäger that where elite unit.
These are historical fact and have little to do with the game.