30mm tubed scopes for hunters?

[Bob Nelson 35Whelen]

I've been "researching" the 25mm scopes in the Leupold VX3 range; interesting ...

@geoff rath
Check out the Meopta 25mm range you won't be disappointed.
Bob

 

[geoff rath]

@geoff rath
Check out the Meopta 25mm range you won't be disappointed.
Bob

Will do; thanks for the "heads up" Bob.

 

[The Engineer]

Just for interest, if you assume the scope tube wall thickness are the same to prevent denting, a 30mm scope is 23% stronger in bending than a 1" scope.

However, one reason for the larger diameter scope tubes is to accommodate the current high zoom power change mechanisms. The 8x mechanism is not only larger but significantly heavier. Both more room for the power changes cams is required and significantly more robust internal structure must be provided for the mechanism.

It was also stated that a 50mm objective will be the same distance above the bore for either a 30mm or a 25mm scope. I take objection to that statement as the minimum distance above the bore is set by multiple constraints. The first mandatory requirement is the objective bell must clear the barrel. Similarly the eyepiece must clear the action as the action is cycled. With a large objective scope eye relieve can impact how far forward the maximum diameter/taper of the objective is with respect to the barrel (IE: If the scope is mounted further forward the taper on the scope and barrel can sometimes allow the scope to be mounted lower without contact.). And as mentioned access must be provided for loading.

In my case I like my scopes mounted as low a possible to obtain a good cheek weld to both lower perceived recoil and acquire the target more quickly. Once I have selected a scope (More on this in the next paragraph.), the process of selecting bases and rings starts. This can be quite tedious as as you first must establish what the minimum mounting height must be and then search the manufactures literature for what mounts/rings will meet that minimum. From my stash of previously used mounts/rings I can usually find a set that will accommodate a 1" scope. I mount the bases and lower half of the rings loosely. Using a 1" dowel or a smaller objective 1" scope, I build up the expected interference point for the objective AND eyepiece by wrapping blue tape smoothly around mockup until I obtain the correct diameters. Setting the taped mockup in the lower scope rings the action can be cycled to check eyepiece clearance and the objective clearance directly observed. If there is clearance it can be measured, if not the mockup can be shimmed up. From the data on the base/ring height and the measurement the minimum mounting height for the scope can be calculate and the appropriate mounts selected. At this point I agree this dimension is independent of scope tube diameter.

When trying to mount the scope as low a possible, the scope selection is critical. I will provide a couple of examples from my experience.

On my 300 Win plains game rifle I originally had a Swaro Z6I 30mm scope. This is a magnificent piece of glass but I did not pay attention to the eyepiece diameter when I purchased it. Because the red dot controls are in the eyepiece it is quite large in diameter and required fairly high rings to clear the rifle's bolt. That mounting did not provide a good cheek weld. I put the scope on one of my single shot rifles where the large eyepiece was not an issue. My replacement scope was a Zeiss Victory HT 30mm scope which had a MUCH smaller eyepiece. This allowed me to mount the scope over an eight of an inch lower than it had been with the Z6i. That does not sound like much, but it makes a significant difference in cheek weld.

On my Heym Martini Express rifle it has European styling included a classic laid down bolt handle. Because of this the bolt handle interferes at the root of the handle and not further out which is more common. In this case there are no bases as the mount dovetail is an integral part of the receiver. Therefore, the selection of rings was a bit limited. Doing quite a bit of research I found two CZ 550 front rings could be used on the Heym and Alaska Arm supplied their magnificent quick removable rings that provided about .050" clearance with the bolt handle root. No lower mounting would have been possible.

 

[The Engineer]

Should have been a 45% increase in bending strength. Stiffness and strength rapidly increase with diameter but I suspect the wall thickness on the average 30mm scope is less than on a 1" scope to reduce weight.

 

[CBH Australia]

@The Engineer thanks for your input.

I new I had read there is an increase in the tube strength relative to tube size.

I think sometimes it's put forward as one of the advantages of a 30mm tube but then as you say it might have a thinner wall to reduce the weight increase that comes with the other features of the scope.

It sounds like the option of a 6x or even an 8x Zoom might be the most beneficial advantage of going to 30mm tubes. Obviously higher quality and better glass are relevant to the make and model but for some a good magnification range in a scope makes the setup versatile for various situations.

 

[Kevin Peacocke]

Since I am mounting my scope on a Ruger No1 I don't need to worry about the bolt clearance. Also, to accommodate the long eye relief required I chose the recommended Swarovski Z6i EE scope which only comes with a 30mm tube. So in my view the choice of tube diameter is dictated by other things, it is not a degree of freedom in engineer speak.

 

[Jon Glajchen]

I too prefer 30mm scopes over their 1 inch brethren, all be it for no logical reason. Perhaps my 30mm scopes are just of slightly better quality and of a higher spec in the product range when compared to those that I have in 1 inch.
I have a Swarovski Z3 4-12 x 50 BT on a rifle and love it for its weight, clarity and ease of operation. It is a 1inch scope.

 

[geoff rath]

Since I am mounting my scope on a Ruger No1 I don't need to worry about the bolt clearance. Also, to accommodate the long eye relief required I chose the recommended Swarovski Z6i EE scope which only comes with a 30mm tube. So in my view the choice of tube diameter is dictated by other things, it is not a degree of freedom in engineer speak.

I'm with you there; most of my rifles are No 1s, so I go as low as I can, aftermarket ribs are available for Ruger No 1s from several reputable sources, only issue is direct importation from the US...

 

[Obi Wan Kenobi]

Does anyone mount 30mm scopes on hunting rifles.

Do you choose it for the tube size or the other specifications like "model" quality/Brand/adjustment? Example my mate likes the Swarovski z6 series.

Do you feel there is any specific advantage?

I know it can offer more adjustment but is there any advantage to the hunter?

I own 41 rifles, only 1 has a 1inch tube.

30mm and 34 mm tubes for me only