Scope diameter

[greyspider56]

I was thinking about preferred scope diameters for F class open, which diameter do you prefer and why? Doesn’t a larger tube provide better light transmission? Thanks in advance
Mike

 

[deadidarren]

Nope but it does give the erector assembly more adjustment room.

 

[Dimner]

The large diameter of the objective lens means more light for sure. As for a larger tube, they keep getting larger and larger. I do not know if it has been scientifically proven that a larger tube will help with light transmission, but I think there is a correlation. We are seeing larger and larger tubes being used with better (high quality) objective lenses and larger objective lenses. So a larger tube might seem like it is helping with light transmission, but I think it's the components that the manufactures are using that go along with the larger tube that make the biggest difference.

 

[greyspider56]

Thanks for your replies

 

[Fast14riot]

30mm will be just fine. F/class is known distance and only 1 distance (even a Palma match is only 8,9,1k). Put a 20 moa rail on it and you'll have more than enough travel for dialing wind.

 

[D-4297]

Maybe ; One of the things that the excessively large tubes do , is allow for seeing mirage , without having to use a spotting scope . Just a slight movement of the rifle will allow mirage to be picked up visually . Don't know if that's a reality , but just thinking out loud . I do it with my TR set-up sometimes .
As far as light into scope , since I live in Arizona and shoot where it is extremely Bright , I keep the Sun shield on my scope , to reduce glare .

 

[searcher]

As a rule, the larger the objective, the more light, and the larger the tube- the more adjustment in elevation BUT, a lesser quality scope that is huge can still transmit poor light. I have a relatively small (2x10, I believe) Nightforce compact scope, for example, that is significantly brighter than some other very high-end scopes I have with significantly larger objectives and tubes. Bigger is not always better - but it usually is with quality scopes. There are a lot of really good 30mm tubes out there. I can't imagine going less than that - but larger is not necessary. There seems to be fewer quality scopes with tubes larger than 30mm to choose from - but there are a few really good ones.

 

[NZ_Fclass]

As a rule, the larger the objective, the more light, and the larger the tube- the more adjustment in elevation BUT, a lesser quality scope that is huge can still transmit poor light. I have a relatively small (2x10, I believe) Nightforce compact scope, for example, that is significantly brighter than some other very high-end scopes I have with significantly larger objectives and tubes. Bigger is not always better - but it usually is with quality scopes. There are a lot of really good 30mm tubes out there. I can't imagine going less than that - but larger is not necessary. There seems to be fewer quality scopes with tubes larger than 30mm to choose from - but there are a few really good ones.

Well, my March HM is 34mm, as is my Burris XTR 8-40. Kahles 10-50 is 30mm as is the Vortex GE and Sightron 10-50. The March and Kahles are both brighter toward the max magnification, but I doubt that the diameter has much to do with it.

 

[std7mag]

The only time I competed in an F-Open match, the best scope I had was a Sightron STAC 4-20X56.
I could still make out the mirage with it.
Plan on doing it again.
But now I have a Sightron SIII 10-50X60.
Both are 30mm tubes.

 

[searcher]

Well, my March HM is 34mm, as is my Burris XTR 8-40. Kahles 10-50 is 30mm as is the Vortex GE and Sightron 10-50. The March and Kahles are both brighter toward the max magnification, but I doubt that the diameter has much to do with it.

I also have a March (though a 10x60x52 objective), as well as several of the Sightron10x50's, neither of which is nearly as bright as most of my lower-powered Nightforce models. I think the brightest scope I own is definitely a Swarovski Z6 in 5x30. Brightness seems to be all over the map on scopes and different models.