30mm vs. 1 Inch scope tubes?

[Bob Nelson 35Whelen]

Why a 30 mm tube on scopes with objective bells...

The 30 mm tube choice has nothing to do with light transmission. The only advantage a 30 mm tube has over a 1" tube on a scope with an objective bell, is that it allows more room internally for a wider range of adjustment of the scope erector, i.e. the mechanism that holds the reticle:

• The reason why European scopes standardized at 30 mm instead of 25 mm is that in days when the tolerances on the mounting of scope bases were much looser than today, a 30 mm scope generally had enough internal adjustment to avoid having to shim the bases and/or the rings. 25 mm scopes often needed external adjustment in addition to internal adjustment. A definite weakness...
• The reason why virtually all modern military scopes have 30 mm tubes is similar, but applied to a different purpose. More internal adjustment allows more elevation clicks to shoot farther.
• The reason why some military scopes are now available with 34 mm tubes is more of the same: more internal elevation clicks for latest longer range loads (e.g. Lapua, etc.).

Why a 30 mm tube on scopes without objective bells...

First we need to explain a little more the exit pupil concept. Yes, human pupil vary in diameter from 2 mm to 7 mm, but the application of this fact has nothing to do with the tube diameter, because indeed whether the tube be 25 mm, 1" (25.4 mm), 30 mm or 34 mm is irrelevant to a 7 mm light beam. Bert the Turtle is correct!

The application of the basic rule that a 7 mm light beam must desirably reach the pupil at full dilatation in low light condition applies to the diameter of the objective. The basic rule is that magnification x light beam diameter determines the diameter of the objective. This is the reason why most European x6 scopes have a 42 mm objective (6x 7mm = 42 mm), most European x8 scopes have a 56 mm objective (8x 7mm = 56 mm), etc.

This is the reason why a straight 1" tube DG scope with 20 mm objective on a .375 H&H rifle that may see yeoman service on a 1 rifle safari involving early or late shooting, is not ideal. Regardless of glass quality, a 1.5-4x20 straight tube 1" scope only produces a 5 mm light beam at 4x (20 / 4 = 5). This typically means 5 to 10 less minutes of shooting light at dawn or dusk, and that may make all the difference in the world, where legal...

Everything else (such as glass and coatings quality) being equal, you will factually see a Leopard at dusk, or a Kudu at dawn, better with a 42 mm objective than with a 20 mm objective because a 42 mm objective will collect a 7 mm light beam at 6x and a 20 mm objective will only collect a 5 mm beam at 4x. The best glass in the world, from whichever manufacturer, will not make up for this. Period.

A straight 30 mm tube DG scope with 24 mm objective is a step in the right direction. At 4x a 24 mm objective gives you a 6 mm light beam. This is not as good as 7 mm, but this is appreciably better that 5 mm.

I personally play the game on both ends: I use a 30 mm straight tube because of its 24 mm objective, and I rarely use it at more than 3.5x because it produces a 7 mm light bean at that magnification, and anyway I do not shoot far in general when I use a DG rifle... and anyway I am incapable of seeing a difference between 3.5x and 4x... and anyway any variable optic from any manufacturer will typically not have the best image quality at max power...

Please note that all these considerations disappear when using the scope in full day light when a younger shooter pupil is shrinking to 2 mm and an older shooter pupil is shrinking to 3 mm. This is why a modern straight tube scope with a lot of magnification still makes some level of sense. It would be a gross misuse of a Z8i 1-8x24 to try to use it at 8x at dawn or dusk because its 3 mm beam would not even carry half the light the shooter could use and would need, but at high noon this 3 mm beam would work just fine. Although why one would want 8x on a DG rifle scope escapes me...

In summary:

1. A 30 mm tube provides a wider internal adjustment range, which may solve a less than perfectly aligned scope mount issue, and which allows more internal elevation clicks, useful for long range shooting;
2. On straight tube scopes a 30 mm tube provides a larger objective diameter over a 1" tube (typically 24 mm over 20 mm), which increases the diameter of light beam reaching the shooter's eye at any magnification considered.

@One day
Every thing you have said is true and correct but
How many times do you hunt DG 20 minutes before dawn or 20 minutes after sunset.

A Z8i is an ideal scope for longer shots in good light as the exit pupil is 3mm the same as the eye. Conversely if the power is set on 1,2 0r even 3 you have well in excess of 8mm exit pupil. Notre than enough for any light. The lower powers combined with the illuminated dot makes for a wide field of view and instinctive close range shooting.
Personally I walk around the bush with my scopes set on 3x good for 10 to 100 yards. If game is further off I have time to wind the power up for the shot.

Leopold got it right with their DG scope a light weight 3x25. It may only have an 18mm usable objective but that still give a 6mm exit pupil, more than enough for pre dawn or dusk. Light weight to help prevent scope slippage under recoil which does happen from time to time .
Bob

 

[Nhoro]

Good informative post

Also, keep in mind that with age, the eyes ability to OPEN as well as close the pupil decreases. So at 20, your eye could adjust from 2 mm to 7mm. At around 50, you are reduced to 3.5 to 5mm. At 70, even less.

At 43, I can already notice that I take small fiddly things over to the window to see. So larger exit pupils on scopes become less help the older you get and you could buy cheaper scopes ironically, just around the time you are making more money and start buying more expensive scopes with larger exit pupils !

 

[flatwater bill]

The OP of this thread asked a question about 1" versus 30mm scope tube comparison. This question, and many many others were addressed. Lots of good data here. But remember that there are dozens of salesmens cliches ....you get what you pay for, buy once cry once...go first class you'll never regret it......and on they go. Pay little attention to the cliches. Remember this: Don't spend so much money for the superscope of your dreams, and find there is little left for the safari it was to be used on. There is a pricepoint that combines reliability, quality, and fairness. That point for me was found on the Leupold HD 5 series. Good luck finding your own price point..........FWB

 

[Bob Nelson 35Whelen]

I have one scope with an IR and find it very useful in low light, especially on dark colored animals.

I didn’t coin this phrase and don’t remember where I saw it, maybe on this website:

“If one puts a five-hundred dollar scope on a two-thousand dollar rifle, one has a five-hundred dollar rifle.”

I do believe in the theory. I don’t have any $2,000.00 rifles and in fact $1,000.00 is what my most expensive rifle cost. I also own nine rifles which I know is a drop in the bucket compared to many members collections. I did pay more for the scope than I did for the rifle on most of my rifles though.

I have scopes with 1” tubes and 30mm tubes and really can’t tell a difference optically. I also believe quite a few 30mm scopes have 1” scope internals which then gives only one real advantage, stronger tube but again i don’t know that it makes much of a difference. I’m content with the strength of my 1” tube scopes.

@Dwight Beagle
Dose that mean my 600 dollar Meopta turns my custom 85 lowall in 22K Hornet at two and a half thousand into a 600 dollar rifle.. If I can see 22 cal holes in a target clearly at 100 yards with my Meopta and has reliable repeatable adjustments that will do me.
Bob

 

[Fastrig]

This is likely true from a glass composition perspective (i.e. most every reputable manufacturer nowadays use Schott glass, or at least BaK4 (barium crown) glass - with some exceptions for the lowest cost scopes / binoculars that still use BK-7 (borosilicate) glass), but this is not quite true overall.

A $250 scope today gets you glued plastic internals. A $750 scope 10 years ago, and certainly a $1,000 scope 20 years ago got you screwed metal internals. This does make a big difference in the ability to withstand recoil and retain zero; predictability, repeatability and consistency of the clicks value; and long term durability.

As to glass treatments, yes today's cheap coatings are yesterday's high-tech coatings, no discussion about that, but what has not changed though is the polishing. I would speculate that highest precision polishing of a 1980 Zeiss with cost-is-no-object West German focus on quality is probably every bit as good, and likely (much?) better, than 2020 mass produced make-it-as-cheap-as-possible continental Asia low cost optics.

As stated before, I agree that a $3,500 scope is likely not needed for hunting, although very pleasurable indeed, but I would not reduce the market to two tiers: $3,500 and $250. My personal sense is that there is an intermediate tier in the $1,000 to $1,500 where I would venture to state that you get 95%+ of the high end quality at 35% of the high end price. This, to me, is the sweet spot if you cannot afford / do not want to afford the very best.

Just my $0.02

Tend to agree with you. The newer “HD” glass in the quote “mid-tier” scopes is awfully good, they are solidly built and can take whatever you pretty much throw at them. I’ve been using the Leopold VX6-HD scopes lately and they are pretty hard to beat, IMHO. Watch for them to go on sale and you can get a damn nice scope form 899-1199 in the 1-6 to 2-12 mag level. They come with nice magnetic flip caps, a quick throw lever, and a ballistic turret. They don’t have a paralax adjustment, but I’ve never had a scope with one so not missing something I’ve never had. The high end Swarovski, etc. scopes are probably better, but two to two and half times better (comparing price), I don’t think so.

 

[Dwight Beagle]

@Dwight Beagle
Dose that mean my 600 dollar Meopta turns my custom 85 lowall in 22K Hornet at two and a half thousand into a 600 dollar rifle.. If I can see 22 cal holes in a target clearly at 100 yards with my Meopta and has reliable repeatable adjustments that will do me.
Bob

It does not. Two of my nicest scopes are MeoPro 3.5-10x44’s with German #4 reticles. There is a point of diminishing returns when you get to a certain price point on scopes. And as stated I believe in the theory. My point was aimed at the guy who puts a Simmons on a Dakota 76.

I’m not ashamed to admit though that if I had the money I’d own some Leica Magnus scopes along with a few Meopta top model scopes. They’d be dandy on my $600-$1k bolt action rifles. I’ve been made fun of for having a VX-3 on my 336W and couldn’t care less.

 

[Dwight Beagle]

As for light transmission...I've never noticed a difference between 1" and 30mm tubes.
The quality of the glass is where I've see a huge difference in lower light conditions.

Ditto

 

[Andrew Short]

The OP of this thread asked a question about 1" versus 30mm scope tube comparison. This question, and many many others were addressed. Lots of good data here. But remember that there are dozens of salesmens cliches ....you get what you pay for, buy once cry once...go first class you'll never regret it......and on they go. Pay little attention to the cliches. Remember this: Don't spend so much money for the superscope of your dreams, and find there is little left for the safari it was to be used on. There is a pricepoint that combines reliability, quality, and fairness. That point for me was found on the Leupold HD 5 series. Good luck finding your own price point..........FWB

I share the same sentiment. Have several Swarovski a but my new DG rifles with have a VX 3i 1-4 and a VX5 HD. The VX5 firedot can be had for $749

 

[Tokoloshe Safaris]

I would rate any scope in this order.1.Reliability. 2.clarity, 3.simplicity. Swarovski and Kahles have always checked all of those boxes. Go with the best you can afford and go with even better, properly installed scope mounts.

 

[fourfive8]

Leopold got it right with their DG scope a light weight 3x25. It may only have an 18mm usable objective but that still give a 6mm exit pupil, more than enough for pre dawn or dusk. Light weight to help prevent scope slippage under recoil which does happen from time to time .
Bob

Astute observation about the Leupold small FX scopes!

As to the OP's topic... I think most of the "buzz" about 30mm vs 1" started several years ago for no other reason than 30mm sounded cooler and more "continental" and therefore the higher cost of some of those optics could be rationalized. Kind of like adding the letter "i" to the end of a sports car's model/name. In practical terms.... ehhh dunno?

There is something to be said about simplicity. Leupold's small lightweight fixed power scopes tend to be extremely durable and practical and affordable. Not a bad thing for those on a budget because it allows another trip or added days or extra trophy fee or two or extra whatever. Plus they have plentiful eye relief. I have found no faults with them- the long eye relief allays any fear (and potential flinch) of scope eyebrow from heavy recoil, they are durable because of both the simplicity of design and inertia physics dictates that more massive objects take more of a beating from recoil as does the mount integrity. And, the small Leupold FXs tend to have generous exit pupil for hasty alignment under stress- not a small consideration for DG application. I've had their 2.5 FX on my 450 Watts for many, many heavy recoil rounds and rough usage- ultimately practical and no issues.

 

[Ray B]

My experience with "exit pupil" is that it doesn't relate to an images brightness. As I understand it, it references the diameter of the beam of light going through the optic lens and to the users eye, with iris fully opened. To me, the intensity of light going through the scope has more to do with seeing than the beams diameter. For example a 3 mm beam that had more candles per square inch than a 5 mm beam would allow better observation. so to me, the quality of the design, glass and its coatings has more to do with a scopes "brightness" than a calculation based on the objective diameter. Only in so far as the tube diameter allows the brightness to proceed through it would once diameter be better than another.

 

[meigsbucks]

I’ve been reading this thread and everyone has given excellent insight into the the variables that need to be considered when choosing a riflescope.
However, I’d like to add my $0.02 worth. I may be mistaken and I apologize if I missed it but something else that enters greatly into the cost of a scope is the magnification factor. For years 3x (3-9x) was the standard and now you can get up to 8x (1-8x). As this factor goes up, so does price.
Another thing that some alluded to is eye relief. Although a majority of mid to higher end scopes have at least 3.5” of ER. However, some may be at that distance at low power but sink to under 3” at high power. Not what you want on a heavy recoiling DG rifle.
Also some 30mm scopes weigh considerably more than 1” models.
Personally I used Leupold VX2 scopes for years and then began buying VX3’s which have served me well. That said, I have since purchased Leupold VX5, mid range Zeiss (Conquest) and Swarovski (Z3 and Z5) scopes which are mounted on non DG rifles. Optically, the higher end scopes provide a sharper image.
I have VX3’s on .375 (1.75-6x), .416 Ruger, and .458 Lott (both wear 1.5-5x). The .375 has well over a 1000 rds, the .416 and.458 are both 500+ rds without failure. (I hope I don’t jinx myself) Eye relief is around 4”. I’ve never had any issues seeing what I was shooting.
I’m not a wealthy man and $2k scopes are out of my budget but choosing a scope I would figure out what features are important to you and buy the best I could afford, 1” or 30mm doesn’t matter, and I would seriously consider an illuminated reticle.

 

[CBH Australia]

Thanks so much One Day for explaining this! So, for a low magnification straight tube as used for DG, a 30mm tube would be best. But for my .375, I could use a 2.5-10 x 44 (or 50) as I have been using for years in a 1” tube on my .338 and there would be no handicap as far as low light shooting goes compared with a 30mm tube? I generally hunt elk in/next to heavy timber and have never had an issue with not being able to see an animal through the scope in low light conditions AND without a lighted reticle! Maybe the heavy timber in Africa is more dense?

He's a thought. For hunting Elk or Eland you might be set up just right.
The same rifle for DG, maybe it's the wrong scope.
Is the heavy timber in Africa thicker? In places maybe compared to what example.
For me shooting smaller animals like feral pigs on dark the low light performance helps.
But, many Sambar hunters in Australia might also want good low light performance within their means.

 

[Bob Nelson 35Whelen]

It does not. Two of my nicest scopes are MeoPro 3.5-10x44’s with German #4 reticles. There is a point of diminishing returns when you get to a certain price point on scopes. And as stated I believe in the theory. My point was aimed at the guy who puts a Simmons on a Dakota 76.

I’m not ashamed to admit though that if I had the money I’d own some Leica Magnus scopes along with a few Meopta top model scopes. They’d be dandy on my $600-$1k bolt action rifles. I’ve been made fun of for having a VX-3 on my 336W and couldn’t care less.

@Dwight Beagle
You have to see it to hit it. My philosophy is to put the best you can afford on your rifle. A VX3 on a 336 is fine as long as it's no a 6 to 24x50. I see so many people putting massive so called tactical scopes on hunting rifles. Totally useless.
My budget only allows Meopta Meopro or Zeiss terra. Covers all my hunting and my finances. Off you can afford a top end scope fine, if you can only afford a Simmons whitetail that's alright by me. As long as they help you place the shot more accurately.
Bob.

 

[Fastrig]

I’ve been reading this thread and everyone has given excellent insight into the the variables that need to be considered when choosing a riflescope.
However, I’d like to add my $0.02 worth. I may be mistaken and I apologize if I missed it but something else that enters greatly into the cost of a scope is the magnification factor. For years 3x (3-9x) was the standard and now you can get up to 8x (1-8x). As this factor goes up, so does price.
Another thing that some alluded to is eye relief. Although a majority of mid to higher end scopes have at least 3.5” of ER. However, some may be at that distance at low power but sink to under 3” at high power. Not what you want on a heavy recoiling DG rifle.
Also some 30mm scopes weigh considerably more than 1” models.
Personally I used Leupold VX2 scopes for years and then began buying VX3’s which have served me well. That said, I have since purchased Leupold VX5, mid range Zeiss (Conquest) and Swarovski (Z3 and Z5) scopes which are mounted on non DG rifles. Optically, the higher end scopes provide a sharper image.
I have VX3’s on .375 (1.75-6x), .416 Ruger, and .458 Lott (both wear 1.5-5x). The .375 has well over a 1000 rds, the .416 and.458 are both 500+ rds without failure. (I hope I don’t jinx myself) Eye relief is around 4”. I’ve never had any issues seeing what I was shooting.
I’m not a wealthy man and $2k scopes are out of my budget but choosing a scope I would figure out what features are important to you and buy the best I could afford, 1” or 30mm doesn’t matter, and I would seriously consider an illuminated reticle.

@Dwight Beagle
You have to see it to hit it. My philosophy is to put the best you can afford on your rifle. A VX3 on a 336 is fine as long as it's no a 6 to 24x50. I see so many people putting massive so called tactical scopes on hunting rifles. Totally useless.
My budget only allows Meopta Meopro or Zeiss terra. Covers all my hunting and my finances. Off you can afford a top end scope fine, if you can only afford a Simmons whitetail that's alright by me. As long as they help you place the shot more accurately.
Bob.

Personally like the new 30mm scopes but the three I have are all the new VX6-HD’s I’ve patiently picked up on sale over the last year, (2) 2-12 and (1) 1-6. Maybe it’s just the improved glass but they do have a better FOV and eye relief than my older 1” scopes. It’s kind of an unfair comparison though as the magnification capabilities between the scopes aren’t apples to apples and the 1” scopes are a good decade or more old, and optics have gotten better in general over time.

I looked at a lot of scopes before going with the new Leopolds, and while God had been very good to me and I can afford pretty much any scope I want, I couldn’t justify the price jump up to the more expensive glass options because I couldn’t see that much of an improvement for two to two and a half times the money. Were the high end scopes clearer, have more features, etc.? Of course, but not enough for me to loosen up my bank account for them as they aren’t going to make any better shot at the distances I shoot, only practice is going to do that. I’m not cheap, but you can only spend it once and I was able to pick up three very nice HD scopes, that more than meet my needs, for the price of one of the premium offerings. The scopes you can get today from $600-$1200 (if you watch the sales) are incredible compared to what we were getting even a decade ago at premium pricing. Meopta, Meopro, Zeiss Terra, Leopold and many other reasonably priced scopes are fantastic buys IMHO.

 

[flatwater bill]

Lon at Toko says it right...........all the clarity and features you love....and the twilight factor and first 10 min of daylight brightness, means nothing if the scope is broken. Reliability (durability and repeatability) are the most important things. And the most difficult to judge out in the parking lot of a box store........I have assisted with drop tests of at least a dozen different brands, perhaps 40 models. Not perfect tests, but useful. The most durable scopes are Nightforce and Leupold in our testing............other solid scopes are Meopta and Zeiss. The scopes that are the most delicate are not always the cheapest.....best of luck on whatever you decide.........FWB

 

[Dwight Beagle]

A VX3 on a 336 is fine as long as it's no a 6 to 24x50.

1.75-6x32 with German #4.

My budget only allows Meopta Meopro or Zeiss terra.

We have the same budget.