30 mm scope tube ?

B

btmj

New member
What are the advantages to a scope with a 30 mm tube, compared to a 25 mm tube? Particularly in a low power application like a 1-4X scope?

Thanks !

Jim
 
The first thing that comes to my mind is better light gathering qualities. In other words better performance in low light.
 
More internal adjustments. The objective lens size and lens quality are more important for light gathering than the tube diameter.
 
I was assuming the difference in tube diameter was with all else being the same. So are you saying a 3-9x40 in 1" tube would not gather less light than the same scope in 30mm?
 
I'm saying "light transmission" is way down on the list of reasons to buy a 30mm scope. You buy a bigger objective lens if you want more light; you buy a bigger tube if you want more internal adjustments. Other benefits are gravy.
 
Thanks, that is good to know. Sorry for being ignorant here but, what do you mean by more internal adjustments?
 
The crosshairs have more range of motion. For dialing elevation and windage, you move your point of aim X MOA or mils up/down/left/right. 30mm tubes allow you to dial more correction before reaching the scope's mechanical limit.
 
+1

Zoomies got it.

All factors need to be equal though. Lens quality, coatings etc.


Also, a 30mm with its larger range of adjustment, will allow the sight plane to remain near the center of the lense, for best clarity.
 
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