Is it all about the lighting?

the 30mm tubes have more room for windage and elevation adjustments.

30mm offers more windage and elevation adjustment range.
30mm is (theoretically) stronger
1" is (typically) lighter in weight
there is no significant optical difference

30mm is of European origin. It is a nice, even metric number. 1" is of US origin and is a nice, even English number. I believe this is why the choice exists - an even number to measure and not really for any technical advantages.

333OKH---Going to a 1" tube has nothing to do with lighting. Going to a bigger bell(objective lens)is for light purposes---to a point it could but maybe not. The ratio of the objective lens to the power gives exit size. In other words lets use a 3x-9x 40MM scope for example. On 9 power, 9 into 40 = 4.444 MM. So you have a 4.444MM exit. On 3 power 3 goes into 40=13.333MM exit. Once this exit is the size of the persons pupil--you gain no more going bigger. As people get older,their pupil gets smaller. A youngster might have a 7MM pupil but older folks dont---thats why it takes us older geezers longer to adjust in a theater. So in the example if a person has a 6MM pupil once they turn the power down to 6.67 or lower---they gain no more light. Go outside at night with a variable scope and start on full power and turn it down and you'll see what Im saying. It will reach a point of brightness but not get any brighter. I have 7x50 and 7x35 binoculars---7.143MM exit and 5MM exit---I can tell no difference but a youngster could.

say I put a Leupold 3-9X40 European-30 on my new custom MRC1999 short action. Do you think it will look out of portion to the gun compared to the 1 inch tube?

quote:

Originally posted by 333_OKH:
say I put a Leupold 3-9X40 European-30 on my new custom MRC1999 short action. Do you think it will look out of portion to the gun compared to the 1 inch tube?

It's in the eye of the belolder, but to my eye, yes, the 30mm is out of proportion with a trim sporter rifle.

By the way, the last time I looked at Leupold's specs, their 30mm tube scopes were shown to have LESS W & E adjustment than the comparable 1" tubes. I don't know whether that is an inaccuracy in specs (common with scope manufacturers) or the gospel truth. If the published specs are accurate, it would call into question why Leupold would even bother to build the 30mm.

IMO, the 30mm tubes have been associated with the better European scopes like Zeiss, Swarovski, Kahles and Schmidt and Benders. 15 years ago if you had a 30mm tube you probably had a superior scope. Not so today. The 1" scope can be as good as a 30mm because they are producing better scopes in 1" tubes.

I have heard that Leupold took a 1" tube scope and put it in a 30mm tube without changing the interior construction for marketing purposes. I don't know if this is true or not.

Comparable 30mm Scope tubes are stronger than 1" tubes. 30mm Scope tubes allow for more internal adjustments. Larger lenses are easier to manufacture to higher resolution. 30mm tubes allow for larger internal lenses. Not all 30mm scopes weigh more than 1" scopes in the same mag and obj range. The bad thing is that they are usually more and sometimes much more expensive.

I have scopes from the same manufacturer in both 1" and 30mm tubes. The 30mm Scopes are better optically - you can see the difference. I don't know if it's because the 30mm scope lenses are easier to make to a higher resolution or if they use better more expensive glass in the high end 30mm tube scopes. But you can tell the difference if you'll take the time to really compare both.
IMO a 2.5-8x32 1" tube scope looks just as goofy on a Beanfield rifles as a 4-16x50 30mm scope looks on a Mountain rifle. There are rifles and hunting situations where 30mm scopes are the best way to go, but in fairness most hunting in the US is probably just as well served by 1" scopes. There are good places for both sizes. I think you should balance the scope to the rifle and what you use it for and buy the best quality optics you can afford. I'd rather hunt with an inexpensive rifle with a really good scope, than an expensive rifle with a cheap scope.........................DJ