I know they are not all fixed, but for the good ole 30-30 these would be my choices...I like the 32mm scopes for the 336 that way you can leave the rear sight on and use quick detach rings...just in case...I don't like the "see-through" style rings at all.
Nikon Monarch 2x-7x32mm. I have one of these on a 336 and I think it suits the gun perfectly.
One of these would be right up the 30-30's alley too.
Bushnell Elite 4200 1.5x-6x36mm might have to use high rings or remove the rear sight.
Bushnell Elite 3200 2x-7x32mm
If she is dead set on a fixed I would go with one of these depending on the money you are wanting to spend.
Nikon Monarch 4x40mm or Nikon Buckmaster 4x40mm. Although, chances are, the rear sight will have to come off.
I think the fixed 6x is a little too much for big game, when using the 30-30. Just my opinion. I have used the 7x on my Monarch on my 336, but not on deer, just coyote and groundhog and 99% of the time it sits on 4x even then.
I would rather be under-magnified than over-magnified.
Stay Safe. Happy Hunting/Shooting.
