On Mon, 17 Nov 2008 16:44:34 -0800, pyotr filipivich
wrote:

I skipped the meeting, but the Memos showed that "DoN. Nichols"
wrote on 17 Nov 2008 22:45:02 GMT in
rec.crafts.metalworking :
On 2008-11-17, Gunner wrote:
On Sun, 16 Nov 2008 23:03:01 -0500, "Buerste" wrote:

[ ... ]

If "extreme range personel interdiction" is more of a primary
concern....get a heavy barreled Savage in .308, and stick on a decent
fixed power scope, somewhere between 8x and 10x.

If anyone wants to know why most specialists prefer fixed power
optics, Id be happy to expound.

Could it be that the position of the cross-hairs shifts relative
to the target when the focal length is changed, so you have to zero it
at one focal length? (Or even worse -- the sliding components which
implement the zoom may shift with recoil, so even if you stay at a given
zoom point the cross hair point will shift.

So far, all good answers.

Now, think about this. With a variable scope, when you get your
sight picture, how "far away" is the target? Well, that all depends
on what power the scope is set at. E.G., if it is set at 9x and
you're thinking "3x" - "Dang that's close up!", and miss accordingly.
It has been my experience that getting everything "right" for a
shot (cheek weld, eye relief, pulse, breathing, tension on trigger,
site picture, etc) is hard enough without adding the variable of
movable optics. At east, that is my experience. But I do love having
the variable scope to double as a "spotting scope" for post shot
target examination.


tschus
pyotr

you would make an excellent student of mine. You got it in the first
go.

Range estimation is the reason.

Range finders can and do take a **** with great regularity. If you
are using a fixed power scope, you can easily, over a short time,
learn to estimate the range, and apply the proper hold over for the
various distances simply by how big the target is in the scope.
Various "sniper scopes" use multiple crosshairs, horizontal lines and
so forth and yes, they can and do work well, but only at one fixed
power. Fixed power scopes tend to be much sharper and can only be
matched by a far more expensive variable. The Shepard and ART2 scopes
are specialist scopes and work well enough with their compensation
mechanics, but are exceptionally pricey and can be a bit fragile.

Standard fixed powers are 8x and 10x. More magnification and it
really magnifies natural body movement, makes mirage far worse and can
really screw things up if the target is "danger close"... Which is one
of the reasons such a rifle really really needs to keep its iron
(preferably decent peeps) sights.

A personel interdiction scope needs to be rugged, reliable, clear and
have good repeatable elevation and windage clicks, perferablly ones
you can hear AND feel. 16th minute is overkill. Quarter minute is
satisfactory. For this sort of application, your target is the size
of a paper plate if you chose to take head shots, which can be very
hard to do past 400 yrds...Center of Mass shots are approx 12" wide by
20" tall and are easily delivered well out past 1000 meters with even
most stock rifles if they are of decent accuracy....IE..if they will
shoot a 1" 3shot group at 100 yrds, they will likely shoot a 10" group
at 1000 yrds (assuming no mirage, no wind etc etc). A round into that
12x20" area is gonna really ruin the targets entire day. If you think
he is wearing armor, then shoulder, pelvic, hip or neck/head shots are
indicated. Letting him hold a 175gr at 2000+ fps in the shoulder, is
likely to be virtually fatal in minutes, given that the bones will be
blown into the body cavity, acting as shrapnel, shreding the closest
lung at the very least. Same with a round into the hip/pelvic girdle.
Unless he has access to a fast dust off, or is hit in the parking lot
of a good trauma unit...he is likely to be toast in short order. At
the very least, he becomes a HUGE problem for his mates.

A variable scope has its uses, as Pytor says. But..and I cant stress
this enough..it should be shot at the same power each and every time.
It should become natural for you to apply the proper holdover at any
range. And most variables have one power that has minimal parallax,
and the best focus and clarity. You must be able to see how the
grass or leaves are blowing, from the muzzle all the way out to the
target..(often more than one direction at the same time) so you can
judge windage.

If you have a variable, find the best fixed power..usually about 2/3
of maximum. and leave it there as you learn the weapon, and if using
it for a spotting scope...ugg....make it instinctive to return it to
your shooting power.

Does everyone understand the concept of what "point blank range"
really is, and why is critically important to know what your
rifle/cartridges BPR is?

Gunner



Gunner