Whats with 3-9x40

Ammunition, accessories and shooting-related gear & equipment - including Optics and Sights.
fantumfan2003
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Whats with 3-9x40

Post by fantumfan2003 » Sun Jan 18, 2009 7:39 pm

All,

This seems to be the most popular zoom range for rifle scopes.
Any particular reasons ?

Manish

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ai

Post by ai » Sun Jan 18, 2009 8:40 pm

3-12X44 is taking over now!

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Re: Whats with 3-9x40

Post by fantumfan2003 » Sun Jan 18, 2009 9:10 pm

Ok, so shooters seem to like it bigger, but why that range ? I saw scopes for sale in a shop, quite a few of them and they were 4x32 and majority, 3-9x40 (or 32)

There must be a reason for that right ?

Manish

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Re: Whats with 3-9x40

Post by Mark » Mon Jan 19, 2009 12:12 am

I'm no expert on optics, so take this with a grain of salt but here are my thoughts on the matter:

Until recently, the zoom range that most scopes could reliably accommodate was 3:1- the highest magnification would be 3X the lowest magnification. Why this was I've heard conflicting reasons why (either the ability was always there but until recently was too expensive to implement, or advances in production technology solved manufacturing hurdles) but if you look at most scopes that is the range, then scope magnification becomes just deciding what compromise works best. Back in the day before variables were considered reliable a fixed 4 power was thought to be the usual best compromise between field of view and magnification. The early variables were usually 3X9 because it offers advantages over the 4X on both ends as an all around scope. This was back when most people here in the US only had one centerfire and used it for most everything small and large.

Anyway, that is just my opinion, hope it helps!
"What if he had no knife? In that case he would not be a good bushman so there is no need to consider the possibility." H.A. Lindsay, 1947

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Post by MoA » Mon Jan 19, 2009 4:16 am

I personally like the 12x42 maginification range, or the 4.5-24 or 4-19 or 6.5 x20.

Depends on caliber and what you are trying to achieve with that caliber. The 12x42 scope in my case costs as much as the rifle... then again I like seeing holes jump around with my heartbeat.

shahid

Post by shahid » Mon Jan 19, 2009 8:57 am

Scopes are made with sets of lenses ( Aspherical groups of lenses ).

For shooting animals in between 50 to 150 yards the besr magnification with a reasonable field of view and perspective judgement is about 4X mag.

If shooting at about 100 yards going beyond 6X mag would make the cross rather unstable on the image of the quarry, i.e. difficult to hold steady as you breather.

At the same time a 9X mag helps spot targets or impact points clearly if a rifle is being sighted.

A group of lenses usually provides a zoom magnifiation in muliples of 3, therefore a group designed to settle at 6 X can be zoomed from 3 X to 9 X.

A scope will work best if set on the middle of this range so about 5 X will give best results with these scopes.

Why we all use still 4 X because earlier popukar scopes were 4 X32 or 4 X40, and we are used to the image view in them.

Another popular medium priced product is a 4-12X 42 but not all rimfires would have enough space to accomodate a 42 mm bell. So the popularity of 32 mm continues.

Today this technology of 3-9X32 or 40 scope production has reached mass production ability and all major manufacturers like Bushnell, SImmons, Weaver, Tasco ( Bushnell ), Nikko Sterling, Redfield, Leopod or Nikon get these down range products made in China or Taiwan.

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Re: Whats with 3-9x40

Post by fantumfan2003 » Mon Jan 19, 2009 11:28 am

I just came across this link

http://www.ehow.com/how_2155753_determi ... rifle.html

So magnification power has got to do with range and target size. Wonder why there are high power riflescopes like 24x and 32x and even 50x, especially used in field target matches.

Is the high magnification so critical in estimating range with a mil dot reticle in FT and HFT ?

Also one can see many scope (high magnification as well) that don't have a mil dot reticle, they have duplex or simple cross hair reticle. So how do they use these reticles in the field ?

Manish

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Post by MoA » Mon Jan 19, 2009 1:25 pm

Manish

You typically will have a ballistic drop chart to use. Additionally a number of scopes have some ranging features built in. An example would the Varmint Reticle on the Leupold VXIII LRT and the NP-1RR on the Nightforce range.

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Re: Whats with 3-9x40

Post by fantumfan2003 » Mon Jan 19, 2009 2:53 pm

MoA

How would the ballistic drop tables apply to scopes on air rifles ? Quite a few of them shoot out to 25, 50, 75 and even 100mtrs/yds

Manish

shahid

Post by shahid » Mon Jan 19, 2009 6:17 pm

By shooting at a target at 10, 20, 25 and 50 meters and observing the pellet drop / rise.

From an Air rifle zeroed at 10 m, the pellet will shoot 1 inch high at 20 m and 1/2 inch high at 25 m. It will level again at 30 m which is really a most frequent game taking range and drop 3 to 4 inches at 50 m.

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Re: Whats with 3-9x40

Post by fantumfan2003 » Mon Jan 19, 2009 6:27 pm

Shahidbhai

Thanks

Wow...just like that ....Amazing

Manish

ai

Re: Whats with 3-9x40

Post by ai » Thu Jan 22, 2009 11:28 am

fantumfan2003";p="64777 wrote:I just came across this link

http://www.ehow.com/how_2155753_determi ... rifle.html

So magnification power has got to do with range and target size. Wonder why there are high power riflescopes like 24x and 32x and even 50x, especially used in field target matches.

Is the high magnification so critical in estimating range with a mil dot reticle in FT and HFT ?

Also one can see many scope (high magnification as well) that don't have a mil dot reticle, they have duplex or simple cross hair reticle. So how do they use these reticles in the field ?

Manish
Manish,
In a variable magnification scope, as magnification is increased, the image loses brightness (because the exit pupils diameter decreases). The field of view also diminishes, and as Shahid mentioned, the image appears shaky. Due to the small size of the exit pupil, the eye must be perfectly allined to the scope to see a clear and full image. If you can rest the rifle and shoot, high magnifications beyond 4-5X is fine. In fixed power scopes, high magnification can give a bright image.

High magnification is not critical in determining range, nor is a mil dot reticle essential. All duplex reticles can be used to determine rough range as per the instructions in their user manuals. Mil dot is precise comparitively, and MOA Scale/dot reticles are even more practical and also synchronize with the adjustments on turrets- they are in MOA unit and not Mils. For ranging, each mil dot scope will have a particular magnification at which the mil spacing holds true (usually 10X). However, high magnification will obviously lead to a better estimate. In Parallax adjustable scopes, high maginification can be used to determine range acurately by focussing on the target image until clear, then reading the range shown on the dial/knob.

shahid";p="64804 wrote: By shooting at a target at 10, 20, 25 and 50 meters and observing the pellet drop / rise.

From an Air rifle zeroed at 10 m, the pellet will shoot 1 inch high at 20 m and 1/2 inch high at 25 m. It will level again at 30 m which is really a most frequent game taking range and drop 3 to 4 inches at 50 m.
Shahid- thats great as a rough guide, but each airgun will have different trajectory depending on its power, barrel length and pellet characterisitcs.

Personally, I've used scopes ranging from 2-7X 20mm to 8-32X50mm. I've settled for 3-12X44mm because that offers a great mix of advantages- manageable scope weight, wide range of magnification for steady image at low magnification, and good range finding ability and spotting ability at high magnification, bright image throughout the zoom range, and sufficient light gathering ability to shoot at upto 75 yards at night (works wonderfully with lit reticle and LED torch).

Hope that helps.

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Re: Whats with 3-9x40

Post by fantumfan2003 » Fri Jan 23, 2009 9:12 pm

Hi ai,

Whats a 8-32x40 like ? Do you have one to see in Mumbai ?

I bought a Bushnell Legend 5-15x40 Mil dot and was literally zapped by the image brightness even at 15X.

I believe using AO for range finding is permitted only in FT but not in HFT, which I find more appealing.

Military snipers carry laser range finders and spotting scope for rangfinding but its always the reticle thats the BUFFU.

My dream scope is the Schmidt & Bender 5-25x56 with the P4 reticle.

http://www.schmidtundbender.de/pm-ii/5- ... -lp-2.html

It will make a worthy, lifelong investment.

M.

ai

Post by ai » Sat Jan 24, 2009 6:49 pm

Manish,

I had a Deben 8-32 Mil Dot, air gun rated. Poor optics, with image getting yellower with increase in magnification. Overall hopeless. The HW90 destroyed it. The dealer swapped it for a Simmons 3-10X Prohunter though.

Bushnell Legend you have is very good. But the MTC I'm using is better optically (and in all departments also), and IMO better than an Elite 4200 4-16X50 I had. The Accushot is also better than the Legend, but the Elite 4200 optics would be similar if not better.

S&B- at that price range, see the OSOptics website for
SN3 5-25. Thats my dream scope- let's see who gets there first??? :twisted:

S&B site in English- http://www.schmidtbender.com/scopes_pol ... sman.shtml

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Re: Whats with 3-9x40

Post by fantumfan2003 » Mon Jan 26, 2009 4:19 pm

MODS

CAN I CLAIM THREAD HIJACK HERE

M.

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