XDM first-person model position when using iron sights is too low before the first shot

[root-talis]

When you select the XDM pistol and aim down the sights, the handgun appears to be too low. After the first shot it snaps to the proper position. After that, if you select a different weapon and then select the XDM, the positioning stays fine.

[T-MaxWiese-T]

"I've found a workaraound for the XDM bug , just set the animation "full" for the equip animation. the pistol now shows in the right position immediately" from Beppe.

[NinesChaosu]

How to fix this? what tool i need to do this