Owner's Manual

8 9
IMPORTANT: Each time you set the Sweet Spot, the body of the
BOSS must be tight against the micro-adjustable lock nut. Failure
to
keep the components tightly locked will adversely affect accuracy.
IMPORTANT: The barrel mounting screw and trigger guard screw on
the A-Bolt should also be fully tightened (Figure 11). If the barrel
mounting screw and trigger guard screw are loose on your A-Bolt,
tighten the barrel mounting screw before tightening the trigger guard
screw. On the BAR, the forearm locking screw should be kept fully
tightened (Figure 12) to obtain, and retain, the best possible accuracy
from your rifle.
N Y L O N L O C K I N G D E V I C E
A strip of nylon in the threaded portion of the barrel helps keep the
BOSS body properly positioned at the Sweet Spot setting. This locking
device keeps the components tight to the barrel, which is essential for
optimum accuracy (Figure 13).
The nylon may become worn with
prolonged use and may require
replacement. Replacement nylon
locks are available from the
Browning Parts Department in
Arnold, Missouri.
FIGURE 13
Nylon Locking Device
FIGURE 11
Trigger Guard Screw
Barrel Mounting Screw
FIGURE 12
BAR Forearm Locking Screw
3 Since the Sweet Spot is listed
as 2.5, the 5 inscribed on the
micrometer adjustment ring
should line up with the index
mark or vertical line on the
barrel (Figure 10).
4 Using the special wrench,
tighten the body of the BOSS
so it is secure against the lock
nut as explained previously.
Your BOSS system is now calibrated
for 100 grain ammunition using a 243 Win. BAR rifle.
M O R E P R E C I S E A D J U S T M E N T S
If you desire to further experiment and possibly obtain even tighter
groupings, turn the micro-adjustable lock nut ¼ of a turn clockwise
and fire your rifle at a safe target. If the group opens up (gets larger),
turn the micro-adjustable lock nut counterclockwise and sight in at
different ¼ turns until you are satisfied with your groupings. Sweet
Spot settings may vary between rifles of identical specifications with
a given ammunition. As in any sighting-in process, the best results
are obtained through systematic trial and error. You may need to
retune the BOSS should you decide to shoot ammunition of
different brands, lots and/or types.
Be sure to keep a detailed record of your rifle’s Sweet Spot
settings, especially if you use your rifle for different game and
shoot different loads.
WHEN ADJUSTING THE SWEET SPOT, NEVER SET THE BOSS BEYOND
THE 10 SETTING. THE BOSS COULD BECOME LOOSE, MISALIGNED
OR DISENGAGED WHEN FIRING THE RIFLE RESULTING IN SERIOUS
INJURY OR DEATH TO YOURSELF OR OTHERS, AND CAUSE DAMAGE
TO YOUR RIFLE.
Example 2: Sweet Spot set at 2.5.
FIGURE 10