What is the chambering of your Ruger? Do you really need more eye relif or just have the scope set further from your eye? A different base could be a solution as Jon A suggested. How does the rifle fit you otherwise? For large people increasing the length of pull can be a solution. Adding a spacer behind the existing recoil pad or a thicker but stiffer pad may do the job. Another solution is to add a muzzle brake
if you don't have one. That can greaty reduce the eye relief requirement. How effective it is depends on the cartirdge, barrel length, and rifle weight.
There is a downside to using a longer eye relief scope than necessary for hunting. Increasing the eye relief will reduce the field of view unless the diameter of the eypiece is increased in the same proportion. THe weight of the lenses in a scope goes up the cube of their diameter, so that's not desirable. The area of field you see for for a given magnification and eyepiece dimaeter must decrease by inverse square of the eye relief. On a scope that is already high magnificatiion chosing a longer eye relief can seriously increase the time it takes to acquire the target. You have to decide if that's a problem for the terrain and kind of game you hunt. Scout scopes or pistol scopes are available with eye relief from 6 to 24", but at more than about 4X magnification the field is so small that target acquision becomes rediculous.
Leupold scopes have long eye relief compared to many other manufacurers and it's enough for most shooters and most practical hunting rifles. Leupold scopes don't give "picture window" views. Leupold is smart enough to know that their rifle scopes are rifle scopes and not spotting scopes. Recoil wil be painful on just about any rifle if 4" of eye relief isn't enough. It could be you aren't adequately controlling the recoil with your hold, or allowing your body and head to move with the recoil. I have several rifles which recoil more than four inches, particularly a 26 lb 50 BMG carbine, but my body and head roll back with the rifle and 4" eye relief is plenty.