I realize that I am also chiming in a tad late here. I would agree that as young as your Grandson is, he should have no trouble continuing to learn to shoot lefthanded, using his dominant eye. I'd not sweat the idea of how hard it might be to find a lefty bolt rifle, as there are other excellent choices that will work perfectly for him. One of the best that comes to mind is the fine Browning BLR, which comes in a lot of great chamberings. The lever is amidextrous and so is the hammer/safety.

A Marlin Lever gun would also work, but it does have a second safety to contend with, although with proper teaching he could just as easily hunt safely (as I do) without using the HBS (hammer block safety found on the Marlins made since 1983). The safety can be used while loading and unloading, but he could simply rely on the original half-cock safety while he hunted.

Nothing wrong with a nice lefty bolt gun, but there are also some very fine lever rifles and single shots, like the Ruger #1, that can be used just as easily by a lefty as a righty. 

Best of luck!!

I would get him the left handed rifle. If he prefers it he will be more comfortable shooting and there for more accurate. I think especially with kids get what they feel more comfortable with and they will enjoy the sport more.

Gentlemen, I have some experience with left eye dominate for a right handed person!  My youngest son has this problem.  He is now 49 yrs old but when he was six yrs old I started to teach him safe gun handling and shooting accuracy.  Like all four of my kids I started them at age six as I was started.   

   This boy was started with little bolt action Colt single shot .22 and we had the  local range to our selves on Mondays while the range was closed to the public.  The Desert sands Rifle Range near El Paso, Texas belonged to a close friend of mine, and I taught all my kids to shoot there when the range was closed.   

  The boy simply couldn’t hit the target at all at 25 yds with the scoped rifle.  We tried and tried but he simply couldn’t hit the bull.  I left him at the bench with the unloaded rifle, and went inside to the coke machine and my friend (owner) was in the office where I was telling him that I thought my son was going the be the only member of my family who simply was not going to be able to shoot at all.  My friend said look at your son out there!  The clouds of doubt went away and the sun shined through.  The kid was shouldering the rifle left handed and looking at the target through the scope!  BINGO! He had a left master eye! 

  I went out to the firing line and handed him a round.  He loaded the rifle and mounted the rifle left handed and promptly put the next 5 shots in the bull!  

 Now I taught all my kids (three boys and a girl)  individually with only me and the kid walking the desert the kid carrying the unloaded single shot rifle or shotgun and I carried the ammo, handing it out one at a time as they learned safe gun handling.  This did two things I watched how they handled the firearm, till they learned to be a safe handler of the firearm.  The second thing it taught was to make the first shot count with a single shot.   

  When it came time for a larger caliber rifle or shotgun, I would build them their first center fire rifle, and had always built on a Mauser 98 CRF action, stocked to fit them, and most times chambered for 243 Win.  The bolt rifle was going to be a problem for the LME kid, and then about the only LH bolt rifle available was a push feed Remington 700 and those rifles had some safety issues, so they were out for a new kid.  To get a decent rifle that could be had in a lot of good chamberings I was left with a Ruger No1 single shot. That rifle could be had with chamberings from 222 to 458 Win Mag, and about everything in between. I promptly bought him a Ruger No1 chambered for 243 Win, and today he has 7 Ruger No1s chambered for that 243 to on in 375 H&H, and one LH Winchester Mod 70 bolt rifle chambered for 375H&H as well.  

 IMO, a left eye dominate right handed person should use a left handed rifle and certainly a left hand cast off double rifle of shotgun!  Most pump or semi-auto shotguns are ambidextrous but almost all doubles, ether O/U or S/S are cast off one way or the other.    

      The Ruger No1s are a very good choise for a beginner’s rifle for safety reasons till they get some field experience!

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This is a good topic as I have the same issue. I struggled with it for a while before I learned how to resolve it. I am right handed but left eye dominate and I used to get highrise mounts so that I could shoot right handed because I thought that was how I was supposed to shoot. I've since changed and primarily shoot leftie with a RH action. My advice would be to learn to shoot both ways. I stuck with RH action because it left me more options when it comes to rifle selection. It's just something to learn to adapt too and shooting from either direction is a huge benefit. Many a time a deer has come into sight from my natural opposite direction. The shot was easy because I was prepared for it. 

Just my $0.02 so take it as such. Would be nice to know the outcome for him though. Good Luck