AR15
Barrel Length
The ideal barrel
length of the AR15 is 16". This length is long enough to extract the
necessary performance from the ammunition and to provide
the accuracy desired, while remaining short enough to be
easily maneuvered in close quarters. The 14.5" M4-style
barrels are very popular, but the legal limitations and
higher costs do not justify their selection over a
standard 16". These barrels need to have their flash
suppressors permanently attached to bring the overal
length to 16"; the standard A2 flashider is not long
enough.
Twenty-inch barrels
are a bit long, and don’t offer the performance increase
over a 16" barrel to justify their length and additional
weight. Anything above 20" detracts from the rifle’s
"all purpose" use, and is for more specialized
applications.
AR15 Barrel Weight
The weight of the barrel on an
AR15 will only
refer to whether the barrel is a "heavy" one or not. The
heavy-barrel (HB) designation means that there is more
metal there. Some of these taper at different points,
either underneath the handguards or from the front sight
on. The HB whose thickness does not vary (i.e. is
maintained from back to front) offers the most durable
design. The 16" barrels are available in a lightweight
configuration, M4 profile (thin under handguards, thick
outside handguards, and with a cutout to allow mounting
of M203, and in a heavy barrel. For this rifle, a
lightweight or M4 profile offers the most advantages as
far as weight and handling.
Fluting
Fluting a barrel on the AR15 will reduce the
weight as well as offer improved cooling, but may reduce
the strength of the barrel. This is a tradeoff that may
go either way- get a heavier fluted barrel, and you’re
at least as well off as the non-fluted barrel. Stick
with a non-fluted barrel on your AR15.
Terminating
For a survival rifle, the benefit
of a flash suppressor is important. The standard A2
flash hider is very good, but not long enough for those
14.5" barrels on the AR15. In that case, a better alternative is to
replace it with the Vortex flash hiders that are most
effective in their role. Many have argued the post-ban
(non-threaded) barrels offer an advantage in accuracy,
but the advantage of a flash hider outweighs this in the
survival situation. Get a rifle with a flash hider.
There are a few alternatives now to the Vortex, and time
will tell how well these fare.
Bayonet Lug
A bayonet lug is for the most part
never going to be used. However, since the flash-hider
is required, the existence of the bayonet lug does not
require any additional effort and should be included. It
is better to have and not need than to need it and not
have it... keep in mind that a bayonet will not fit
correctly on a 16" barrel; it will fit a 14.5" barrel.
Twist
The barrel’s twist rate refers to
the distance a bullet travels in the barrel to complete
a full revolution. For instance, a 1/9" twist means that
the bullet will make a complete revolution for each 9
inches traveled in the barrel. Heavier bullets require a
faster twist rate to stabilize them correctly, but too
fast of a twist rate will potentially cause a bullet to
spin apart. For this reason it is important to match a
barrel to the bullets being fired. In selecting a single
twist rate for the survival AR, either a 1/7" or a 1/9"
will serve the purpose best. These barrels are designed
for bullets from 55 to 62 grains, and these are the
weights that will most likely be used in survival. The
1/9 is the better of the two, but the majority of
Colts/military barrels are 1/7.
Chrome
An AR15 survival rifle should have a
chromed bore and chamber. The smooth, hard chrome finish
offers increased longevity and facilitates the task of
cleaning. It is also more resistant to the effects of
oxidation.
AR15 Stock
While an argument can
be made for the superior sturdiness and reduced
complexity of the fixed stocks, the telescoping stock
offers advantages in storage and carry, and is strong
enough for rugged use. It also offers flexibility in
stock length, useful when wearing body armor or thick
clothing. While perhaps not as rigid as the standard
stocks, the advantages of the telescoping stock make it
the "ideal" choice.
The telescoping
stocks are available in either an aluminum or plastic
construction, both of which are strong enough for the
purpose, but the aluminum have a tendency to shatter if
hit. They are also offered in 2, 3, or 4 position
varieties representing how many positions it locks open
in. The 3 or 4 position stocks are desirable to offer
the flexible stock lengths necessary when either smaller
individuals are using the rifle, or when thick clothing
or body armor are used. The best of these is the Colt M4
stock, which is a plastic,4 position stock. Bushmaster's
stock is also pretty good, and I would not recommend on
that wasn't Colt/Bushmaster.
