A couple
of months ago I referred to the Nikon Fieldscope III as probably the best 60mm
spotting scope around. I know the 80mm’s are all the rage right now, but there’s
a lot to be said about the 60’s, especially if it’s a good one.
For one, there’s the size issue. Bigger is often better, but not always. A big
scope is, well, big. Therefore, it’s harder and more awkward to carry around. It
takes up more room in your shooting bag. It’s heavier, and heavier scopes mean
that you need a beefier (more expensive) tripod to mount it on.
To illustrate this point, I was spotting for a friend of mine recently who was
using a light weight tripod for a relatively large scope. Man, this scope
wiggled and shivered on the tripod every time I even thought of touching the
focus knob. Additionally, every time a random gust of wind came along, it was
the same story all over again. Trying to spot the targets while the image was
jumping and bouncing around like a 52 Plymouth with no shocks was tough. This
was a nice scope but it’s size wasn’t well matched with the capability of the
tripod. Have you priced good quality tripods recently? A heavy duty model
suitable for a big 80mm scope isn’t cheap. In fact, they’re darn expensive.
They’re also heavy by design. So now this weight issue is getting even bigger. I
won’t beat this point to death, but while the 80’s provide unparallel brightness
and extra wide field of views, there’s a lot to be said for portability, ease of
use, and yes, even lower price tags.
The Fieldscope III’s body is fairly compact, only 11 inches long. It’s also made
of a metal alloy (no plastics allowed) but even so, it weighs in at reasonable
2.3 pounds. It’s fully weather proof, water proof, and nitrogen filled as well.
Go ahead. Tie a rope around it and use it for a boat anchor if you want. Won’t
hurt it a bit. The lenses are all high quality optical Nikon glass and are fully
multi-coated. That means ALL the lenses in the scope are covered with multiple
layers of optical coatings to enhance contrast, eliminate reflections, and allow
the maximum amount of light through the system. It also means the lenses are so
coated on BOTH sides - front and rear. A lot of scope makers will single coat or
multi coat on just one side of the lens to save money. Or they may multi-coat on
one side and single coat on the other. There’s all kinds of ways to pinch a
penny in the manufacturing process at the expense of performance. Not Nikon. You
get the whole optical enchilada with nothing held back.
Like many scope manufacturers, Nikon sells the scope body and the eye pieces
separately. That way you can match the particular eyepiece you want to the
scope. You have more choices then. If you want flexibility, you can go for a
variable power eyepiece. If you want to save some bucks, you can go for a single
power eyepiece. Choice is always good.
It’s also important to know that the quality of Nikon’s eyepieces is perfectly
matched to their scope bodies. Like the bodies, the eyepieces are also fully
waterproofed and the lenses are also fully multi-coated. However, this isn’t
always the case with other manufacturers. Be very careful if you should buy
another brand of spotting scope. That other guy’s eyepiece may not be
waterproofed and multi-coated unlike the scope body. Some other manufacturers
will skimp here. It’s not unheard of that during rainy humid conditions, that
the eye piece on lesser scopes will fog up while the body will be perfectly
clear.
When using the Fieldscope, there’s a lot to like. For instance, there’s a huge
rubberized focusing ring located in the middle of the scope body. This
eliminates any fumbling around when focusing while your eye is glued to the
glass. There’s also a very effective sliding sun shade. Image quality is Nikon
excellent and there’s plenty of eye relief so guys like me that wear glasses can
see clearly without having to press our cheaters directly against the eyepiece.
Edge to edge definition is as good as it gets and the brightness is the best
I’ve seen in a 60mm.
With spotting scopes however, besides brightness, resolution, or the ability to
distinctly see small details, is paramount. To evaluate this, I again used the
homemade resolution chart that I described in last month’s column. This is just
a series of “O’s” laid out in rows in type sizes varying between 72 and 12. In
other words, the top row would have a series of O’s in large 72 type. The next
row would be in 48 type. The third row in 36 type etc. Anyone can make one of
these charts with their home computer. The idea here is to identify the smallest
type size that you can see distinctly. Any size smaller than that will appear in
the scope to be barely recognizable as O’s, and anything even smaller, will
appear just as a fuzzy solid line.
The Fieldscope did very well in the resolution examination. 24 size type was
clear and distinct with no ambiguity and even 18 size type was recognizable. I
compared this to another 60mm scope that I’ve used extensively and have always
been completely satisfied with - the Bausch & Lomb Discoverer, which allowed me
to see .224 sized holes in my 200 meter cardboard practice targets. The best the
B&L was able to resolve distinctly was 36 size type.
In a somewhat more practical evaluation, I took the Fieldscope to my local range
where there’s a set of power lines running 300 meters beyond the ram berm i.e.
500 meters off. This distance has been confirmed by my friend Ron Sadler who
owns one of those big Swiss- made optical artillery range finders. I then set
the variable powder eyepiece on 20X.
The temperature was in the mid 90’s and so there was plenty of mirage in the
image. Never the less, I was able to clearly see that each ceramic insulator on
the distant pole had five horizontal ribs down its length. With the B&L scope I
couldn’t see any ribs at all, much less count them. I then pointed the scope at
a truck stopped at a dumping station in a rock quarry 1000 meters away. With the
Nikon I could see that the driver was in the truck and that he was wearing a
white T-shirt and a red baseball hat. With the B&L, I couldn’t tell whether
there was a driver in the truck or not. The Nikon works.
Lastly, there’s the Nikon warrantee. The Fieldscope is warranted against defects
in materials and workmanship for 25 years. Not bad. Also, if you should happen
to accidentally drop your scope off the edge of your balcony ten stories up
(your fault, not theirs), Nikon will fix your scope for only $10. Pretty good
deal.
In summary, the Fieldscope III is a premium quality product that’s more than a
pretty face and a fancy name. It delivers high quality performance at less cost
than the 80mm’s and in a more user friendly, nicely compact package. It fits.
If the price of the Fieldscope III doesn’t fit your budget, then take a look at
Nikon’s 60mm Earth & Sky spotting scope. Not as many features, but nice price.
Some Basic
Ballistics
Bullets flying through the air are subjected to some very interesting
forces, some of which are counter intuitive. Yet, for the serious handgun
shooter an understanding of some of the basics is important so we can
tailor our loads to best fit our needs. This is especially true when it
comes to the choice of using either flat base or boat tail bullets.
When a flat base bullet is whistling along through the atmosphere, it’s
moving aside a volume of air equal to its own volume and thus creates a
partial vacuum immediately behind its base. As they say, nature arbors a
vacuum and the surrounding air then rushes into this area. The air
collapsing at high velocity into this vacuum creates turbulence at the
base of the bullet - lots of it, and that turbulence creates drag - lots
of it. In fact, at velocities below the speed of sound (1100 fps depending
on altitude, temperature, etc.) that turbulence is THE number one source
of drag on the bullet and will do more than anything else to slow it down
even if it should have a blunt nose like a typical revolver silhouette
bullet.
At speeds above 1100 fps, base drag is still a factor, but another
situation raises its ugly head to slow our bullet down even more. At
supersonic velocities, the air is being compressed ahead of the bullet
faster than it can be displaced. It then gets compacted into a dense shock
wave that’s pushed ahead by the nose of the bullet. In other words, the
bullet is now trying to fight against an even thicker layer of air.
Result? Yep, more drag and more velocity lost. Nose drag now becomes the
number one source of our diminishing velocity although base drag is still
doing its thing as well.
So, what can we do about it? Well we can taper the base of the bullet.
Boat tails on commercial bullets will still have a flat base but now it’s
much smaller and so while there’s still going to be some base drag, it’s
going to be much less than if the base was the full diameter of the
bullet. Additionally, the boat tail is going to smooth the air flow around
the base in a much more smooth and orderly way and so will also reduce
turbulence. Ideally, a pointed boat tail would be the ballistically
optimal design, but I suspect there are manufacturing difficulties in
producing such a base.
Now that we’ve reduced base drag, what can we do to reduce or eliminate
that nasty nose drag? Simple. Use velocities less than 1100 fps. That way
the shock wave is totally avoided because you never create it. And when
shooting at less than 1100 fps, how do you reduce base drag as well? As we
said before, use a boat tail bullet.
Sound familiar? Yes, this is the classic J.D. Jones 300 Whisper principle
i.e. shoot 220 grain 30 caliber boat tail bullets at subsonic velocities
in a fast twist barrel. In a previous article I did on the Whisper I found
that when fired at a velocity of 1050 fps, a 220 Sierra boat tail would
lose only 67 fps at 200 meters. Only 67 fps! At 200 meters! Why so little
velocity loss? Drag, or more properly, lack of drag.
A boat tail makes all the difference in the world. While it will reduce
drag at all velocities, it actually has the greatest effect at subsonic
velocities. Consequently, boat tails are a more important design feature at
subsonic speeds (where they’re hardly ever used) and at long ranges (where
the bullet slows down to subsonic velocities before it hits the target)
than at fast speeds. (J.D., you’re one very smart guy.) A boat tail is far
less effective at supersonic speeds (where it is always used). Doesn’t
make much sense, but there it is.
This whole situation sounds ideal for a heavy cast bullet with a boat tail
as regular commercial jacketed boattails are usually pretty expensive.
However, no one I know makes such a mold because you can’t put a gas check
such a bullet. However, a gas check isn’t really needed, since the idea is
to never go over 1100 fps. Sounds like a interesting project for someone.
Anyone interested?
Sinclair International Calendar
Here it is the middle of July and I’ve already got a new calendar for
2003. You probably think I’m nuts to get one so early, but this particular
one is special. No, it’s not from any of the publishers of the various
girlie mags, but rather from Sinclair International - home of the
precision reloader’s catalog super store. The name of the calendar is
“Rifles: Past & Present” (Yes, I do own and shoot rifles as well as
handguns, but don’t tell anyone.) This thing is gorgeous with exceptional
photography of vintage, competition, and varmint rifles along with the
story behind them. It sells for $14.95 and is perfect to hang over the
reloading bench. I’d be a nice gift for your father-in-law as well. Check
it out and visit them at their web site at
