Wonder if a PTRD with 5 ft long barrel is stable enough

for ELR , rebarrel to 416 and use our 416 HSM, 500 gr bullet ....

.Here is up north guy using 585 HE in a PTRD with inserts,

Light load.....Inserts are in the shape of the 14.5mm case....

https://www.youtube.com/watch?v=jyabm-cbwgc&feature=youtu.be

HERE ia video, 585 Hubel Express and water jugs - slow motion

750 gr with 155gr RE17, just a moderate load.....Ed

https://www.youtube.com/watch?v=uXAo1mJqw8Y