I'll give you the straight review on it brother..
you won't be able to put that ring around the end of the site that is on your 336 now.,,,the site is too high..Also I read a review on them from Cabelas..Folks who are not mechanically inclined will break them..They are fragile..You wil need a small 3 sided file to dress up that front site..it will not fit from the package..it took me a good 20 minutes to finesse with it,,then I carefully tapped the front site in with a small punch.
The rear site is easy but cheap..much like a pellet gun site..I'm real careful when pulling the rifle up to my climber with a rope..not to bump the rifle along anything..
Positive..it shines man..and my eye sight is going ..it shines right up till dark..it sites in good..My groups were in a quarter when I left the range..Teh rear site will nearly max out in height though becasue of the tall front site.
Summary ..worth the money and the hassle..I missed a once in a lifetime buck last year..never again.