I am frequently asked by fellow law enforcement professionals as well as
self-reliant minded individuals:  "what type of scope should I put on my
rifle".    

To answer this question I would have to know the kind of rifle, the rifle's
intended use as well the range limitations that the rifle would be deployed
under.  Upon answering these questions, a suggestion may be made to enhance
the shooter's capability with his weapon.

Question #1; What kind of rifle?  I won't attempt to categorize every rifle,
but rather break them into two categories:  Bolt action/sporting and Assault
/Battle rifle.
For Bolt action and sporting rifles, utilized primarily for hunting, a
standard scope will usually do fine.  The advantage of a bolt action rifle is
in it's inherent accuracy.  Precision shooting, especially at longer ranges
will require the increased magnification of a scope.  These weapons are not
magazine fed, have a significantly lower rate of fire, and limit the shooter
to a narrow field of view for possible follow-up shots.  

Magazine fed Assault rifles are generally less accurate than bolt action
weapons, but have a significantly higher rate of fire.  The addition of a
combat optical sight will increase your capabilities with your chosen battle
rifle.  A combat optical sight has little or no magnification, wide or nearly
unlimited field of view, rapid and in many cases low light sight aquisition,
and high durability.  Excellent examples include, but are not limited to:
 Trijicon ACOG's TA-11, TA-01 and OEG (imported from Isreal under Armison),
Canada's Elcan, Aimpoint and many others.   

Question #2; intended use?  Obviously a survivalist will want a versatile
weapon, capable of procurring meat, and dishing out a little pain to the
raiders attempting to take his water/food supplies.  There are a number of
both bolt action and assault rifles that will perform more than adequate at
both roles with a variety of optics mounted.  I wouldn't discourage
versatility but, as with other tools, specific firearms for specific jobs can
mean success over your enemy, and success means surviving.  As a general rule
wild game dosen't shoot back, making rate of fire less important.  Armed
marauders have the capability of shooting back, which may require more than
just one or two accurate shots.  For one precise shot the high magification
of a scope is necessary.  For rapid, accurate multiple shots, the
wide/unlimited field of view of the combat optics are helpful.

Question #3, What range limitations will the rifle be utilized under?  My
arsenal has a number of both bolt action and assault rifles, each intended
for use at different ranges.  It is unrealistic to carry three or more rifles
while patrolling like clubs in a golf bag,  expecting to pull the optimal
weapon for each individual situation.   Rather, if given the chance, you must
chose the battle to take advantage of your weapons advantages and your
enemies weapons deficiencies.  For example, should you observe an intruder
sneaking near your position with a bolt action sniper rifle, while you and
your party are armed primarily with AR-15s.  To reduce the advantages of his
highly accurate bolt action rifle you should wait or make a hidden move to
close the distance before confronting/attacking the adversary.  At closer
ranges, the high rate of fire from your AR-15 will give you a distinct
 advantage over his bolt gun.  As a general rule, the longer the range you
intend to utilize your rifle, the higher the required magnification.
 Military sniper doctrine discourages engaging soldiers at ranges less than
400 yards for a variety of reasons, to include making use of your weapons
ballistic advantage over standard infantry shoulder weapons.  Engaging
targets at less than 400 yards brings you within the effective range of the
assault rifles, and allows the enemy to spray your position with a higher
rate of fire.  The choice of optics for a sniper rifle would be a scope with
a magnification of at least X10 power, a range finding reticle (mil dot) and
target turrets for range adjustments (dope changes).  

There are a multitude of optical choices on the market, so I will limit this
discussion to units with which I have dirrect knowledge.  In trying to
determine which scope is best for a long range precision rifle the your
choices are unlimited, and I wouldn't attempt to make recomendations.  As far
as combat sights go, the following are a few examples that I feel would
adequately fill your security needs:
  
Trijicon's Armison OEG.  The OEG is an optical tube that requires binocular
vison to employ.  Myself and many of my team members brought these inexpesive
sights for use in South/Central America for mounting on our CAR-15 .223 colt
carbines.  The sight gives no amplification and cannot be viewed through.  To
utilize, the shooter must have a cheek weld that will enable him to see a red
laser like dot inside of the tube with his viewing eye (right eye for right
handed shooters).  With the proper cheek weld and an upon opening the
non-viewing (left) eye, the red dot (your sight and point of impact) will
appear to float into the air, with an apparent unlimited field of view.  The
unit is quite simple to use, allowing you to maintain a view of your target
and the relation of your sight to the target during recoil and rapid fire.

Advantages:
1) Cheap, approximately $150.00 to $200.00
2) No batteries required.  Tritium cell lasts approximately ten years.
                 
3) Nearly unlimited field of view. 
4) Rapid sight aquisition with very fast follow up shots.
5) Mounts easily on Colt AR-15 carry handle (and other carbines) and allows
use of iron sights.
6) Red laser type dot easy to aquire in limited light, allowing sight
aquisition regardless of light conditions.  
recommended for short barrel AR-15 (or similar) type rifle with a large
magazine capacity and high rate of fire.

Disavantages:
1) No amplification.
2) Not effective past 200 yds.
3) Red dot is large covering up target at extended ranges.

Trijicon ACOG TA-11 and TA-01
These two combat sights take the idea of the OEG and add maginification.
 3.5X35 for the larger model and 4X32 for the smaller.  Both are state of the
art (and carry the applicable price) combat sights highly recommended for
your most prized battle rifle.  Both have a number of reticle options, which
include range drop scales, depending on your needs and preferences.  What's
nice about these sights is the ability to use constantly with both eyes open,
making target aquisition immediate.  For example, from a fortified position
you observe a large number of marauders moving to overtake your positon.
 Utilizing the most basic ifantry movement techniques, each raider
individually rises momentarily, runs a few steps toward your position, and
quickly dives behind cover.  

While placing multiple shots on one partially exposed target, your
non-viewing (left) eye observes with peripheral vision another enemy quickly
rising to move toward you to at a closer (or farther) range approximately100
yards (or more) to the side of the soldier you were firing on.  Keeping your
non-viewing (left) eye on the new target, you slightly pan the rifle toward
him.  While the rifle moves, your magnified view will become blurred, but you
will still see your sight reticle.  Upon placing the reticle on the new
target, the rifle will stop moving, your blurred sight picture will become
clear and your brain will automatically switch to focus your attention on the
magified view.   POW, you got him, it takes less than a second and you never
closed your left or non-viewing eye.  I have the 3.5X35 (larger model) on an
H&K SR-9 (accurized polygonal barrel HK-91), and have made rapid shots on
momentarily rising man sized silhouette targets at 400-700 meters on a
military M-60 range. 

Advantages:
1) No batteries required.  Tritium cell has ten year life.
2) Highly durable.
3) Wide/unlimited field of view.
4) Rapid sight aquisition.
5) X3.5 magnification more than adequate for battle situations  
6) Sight aquisition regardless of light conditions.
Recommended for magazine fed battle rifles capable of firing near 600 meters
accurately.

Disadvantages:
1) High cost, these units start near $600.00
2) Low magnification not intended for precise long rang shooting (head shots
at 500 meters).

Note:  Canada exports the Elcan sight which costs a little less and is very
comparable to these sights.  

In looking to equip your rifle with optics, I hope that my comments at least
placed you in the right dirrection.  I would readily answer any specific
questions via E-mail at AshiWaza1@aol.com.