1 inch vs 30mm scope tube

[TassieTiger]

So I’ve got both 25.4 and 30mm scope tubes on various rifles.
A couple of days ago I looked at one of the clearest scopes I’ve ever seen and that had the smaller 25mm tube - so this had me wondering, what are the real benefits of the larger main tube ? Given I’ve bought the smaller tube / what am I effectively giving up ? Why was there a move away from 25mm scopes ? Is it true that 30mm tubes allow more light to pass ? I’ve seen some tubes now at 34mm and done are bigger - is this advantageous or a bigger must be better mentality?
Obviously, the larger tubes would allow for more internal adjustment, probably more expensive generally, stronger? maybe...but optically, are there any significant differences for the hunter / target shooter ?

[Harrynsw]

I do believe it relates to the amount of elevation and windage you can achieve...
And would I be wrong in saying that the size of the eye box is relative to the tube size??

[bladeracer]

I do believe it relates to the amount of elevation and windage you can achieve...
And would I be wrong in saying that the size of the eye box is relative to the tube size??

Not really. My 25mm Bushnell 4.5-18x40 has 105 minutes of elevation.
My 34mm 10-40x50 and 35mm 10-40x56 have just over 40 minutes.
I think magnification is the big limiter of adjustment, not tube diameter.

[Blr243]

On my back up 243 I have what vortex call their hog hunter model with an illuminated reticle 56 mm up the front and 30 mm tube Supposed to be for hunting in the moonlight or low light. Down size is weight and puts the balance of the outfit way off.

[solarpak]

I agree with Harry - more internal adjustment

C.

[Stix]

Ive been led to believe its the adjustment value/more elevation & windage adjustment in a wider tube...

But ive never bothered to investigate it...

I cant help but imagine there would be at least some difference in the resolved image at the other end one way or the other, but if there is, i doubt the human eye would be able to pick it up...

[solarpak]

Stix,
i am a fan of lightweight scopes - anything under 500 grams is perfect on a stalking rifle . Some modern scopes weight 700 grams plus !! (maybe i am getting too soft in my old age - if you call 50 old!!)

C.

[SCJ429]

Obviously, the larger tubes would allow for more internal adjustment, probably more expensive generally, stronger? maybe...but optically, are there any significant differences for the hunter / target shooter ?

Larger internal lenses will perform better than smaller ones but the advantage is only small.

[SCJ429]

Your exit pupil is determined by the objective lens size devided by the magnification. Having a larger tube will not allow any more light to be captured, all things being equal.

[Lorgar]

There's an argument to say the optical performance of larger tubes is better, but I think it's largely a moot point these days really.

Technically, the internal lenses of a 30mm can be larger meaning more light transmission, but really... materials, coatings, manufacturing ability etc. are all so good now on quality scopes, and have been for years, that you're splitting hairs at a technical level rather than a practical one IMO.

There are loads of excellent clarity scopes with 1 inch tubes that are perfect for their intended use.

[straightshooter]

30mm scopes generally have the capacity to be stronger, more rigid, provide more internal room for bulkier internals and for easier assembly and / or more adjustment range.
The amount of light entering a scope is determined purely by the unobscured size of the objective assembly.
Similarly the field of view is determined by the size and design of the ocular assembly.
Clarity is determined by optical design, quality and precision and surface finish of lenses, precision of assembly of all internal components and elimination of internal reflections. However there are many individual perceptions of clarity.
Brightness is determined by the unobscured size of the objective, the number of lenses light has to pass through and the effectiveness of lens coatings if any.
The visual acuity of the user also plays an important role.
Most other perceptions are the consequence of having been moulded by advertising and are generally misleading or erroneous.

[TassieTiger]

Interesting comments - makes you wonder, if there are benefits for say dedicated target shooters, why not move to 40 or 45mm tubes ?

[GQshayne]

Interesting comments - makes you wonder, if there are benefits for say dedicated target shooters, why not move to 40 or 45mm tubes ?

Diminishing returns perhaps.

I reckon just buy what suits the need, be it 25 or 30. In my case I wanted a quality 1-6 wide angle scope with illuminated reticle. As it happens, it was a 30mm tube. Not a factor in the purchase though. I now have 3 of them though, so make of that what you will.

[Stix]

Interesting comments - makes you wonder, if there are benefits for say dedicated target shooters, why not move to 40 or 45mm tubes ?

Extra weight of scope due to excess alloy's & weight of bigger glass...centreline height of exit pupil above scope/lack of cheek weld...cost of manufacture, not just in re-tooling the Chinese lego style assembly line, but more so the optical/lens manufacturers,...bla bla bla...all versus the already excessively overpriced cost of a CNC machined 20/30MOA pic rail or equivelant scope/scope base spacer...

Nah...not gonna happen...not for target shooters anyway... just watch any LR steel ringing hoorah & you'll see they get a real woody from dialling them turrets mate...& i mean a real woody...nothing they'll want you to take away from them...!!...

[Ziege]

s**t I hate exposed turrets on a scope, it's the worst. My 5c haha

[bladeracer]

s**t I hate exposed turrets on a scope, it's the worst. My 5c haha

I'm the opposite, I hate capped turrets. Don't you find them a pain when you went to dial up those long shots?

[Ziege]

I'm the opposite, I hate capped turrets. Don't you find them a pain when you went to dial up those long shots?

Never had to, taken plenty of s**t out to 500m and even a few thing a fair whack further and never needed to dial in anything, infact after dealing with blokes and their constant scope ****** I won't hunt with anyone that keeps piss farting around with their scope, it's never worth it. They, at least in my experience, always lose the opportunity for a shot or miss anyway, meanwhile ya stuck waiting for them to mess around with it all day, better policy, practice holdover and get good at it. That's how I take all my shots, and why mildots exist.

[Harrynsw]

This is a cut and paste from the vortex website

- 30mm main tube offers improved windage and elevation adjustment along with greater strength.